Moa
Encyclopedia
The moa were eleven species
(in six genera) of flightless bird
s endemic to New Zealand
. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about 3.7 m (12.1 ft) in height with neck outstretched, and weighed about 230 kg (507.1 lb).
Moa are members of the ratite
group in the order
Dinornithiformes. The eleven species of moa are the only wingless birds, lacking even the vestigial wings which all other ratite
s have. They were the dominant herbivore
s in New Zealand's forest, shrubland and subalpine ecosystems for thousands of years, and until the arrival of the Māori were hunted only by the Haast's Eagle
. It is generally considered that most, if not all, species of Moa died out by Maori hunting and habitat decline before European discovery
and settlement.
The kiwi
were formerly regarded as the closest relatives of the moa, but comparisons of their DNA in a paper published in 2005 suggested moa were more closely related to the Australian emu
and cassowary
. However research published in 2010 found that the moa's closest cousins were not the emu and cassowary but smaller terrestrial South American birds called the tinamou
s which are able to fly.
Although dozens of species were described in the late 19th century and early 20th century, many were based on partial skeletons and turned out to be synonyms. Currently, eleven species are formally recognised, although recent studies using ancient DNA
recovered from bones in museum collections suggest that distinct lineages exist within some of these. One factor that has caused much confusion in moa taxonomy is the intraspecific variation of bone sizes, between glacial and inter-glacial periods (see Bergmann’s rule and Allen’s rule) as well as sexual dimorphism
being evident in several species. Dinornis seems to have had the most pronounced sexual dimorphism
, with females being up to 150% as tall and 280% as heavy as males—so much bigger that they were formerly classified as separate species until 2003.
Although moa were traditionally reconstructed in an upright position to create impressive height, analysis of their vertebral articulation indicates that they probably carried their heads forward, in the manner of a kiwi. This would have allowed them to graze on low-level vegetation, while being able to lift their heads and browse trees when necessary.
Ancient DNA
analyses have determined that there were a number of cryptic evolutionary lineages in several moa genera. These may eventually be classified as species or subspecies; Megalapteryx benhami (Archey) which is synonymised with M. didinus (Owen) because the bones of both share all essential characters. Size differences can be explained by a north-south cline
combined with temporal variation such that specimens were larger during the Otiran glacial period (the last ice age in New Zealand). Similar temporal size variation is known for the North Island Pachyornis mappini. Some of the other 'Large' ranges in variation for moa species can probably be explained by similar geographic and temporal factors.
Sometimes, the Dinornithidae are considered to be a full order
(Dinornithiformes), in which case the subfamilies listed below would be advanced to full family
status (replacing "-inae" with "-idae").
Thus, the currently recognised genera and species are:
) forests that included Anomalopteryx didiformis and Dinornis giganteus; and 2. The fauna of the dry rainshadow forest and shrublands east of the Southern Alps
that included Pachyornis elephantopus, Euryapteryx gravis, Emeus crassus and Dinornis robustus. The two other moa species that existed in the South Island; Pachyornis australis and Megalapteryx didinus might be included in a ‘subalpine
fauna’, along with the widespread Dinornis robustus. P. australis is the rarest of the moa species, and the only one yet to have been found in Maori middens. Its bones have been found in caves in the northwest Nelson
and Karamea
districts (such as Honeycomb Hill Cave
), and some sites around the Wanaka
district. M. didinus is more widespread. Its name ‘upland moa’ reflects the fact its bones are commonly found in the subalpine zone. However, it also occurred down to sea level where there was suitable steep and rocky terrain (such as Punakaiki
on the west coast and Central Otago
).
. In the North Island, Dinornis novaezealandiae and Anomalopteryx didiformis dominated in high rainfall forest habitat; a similar pattern to the South Island. The other moa species present in the North Island (Euryapteryx gravis, E. curtus, and Pachyornis geranoides) tended to inhabit drier forest and shrubland habitats. P. geranoides occurred throughout the North Island, while the distributions of E. gravis and E. curtus were almost mutually exclusive, the former having only been found in coastal sites around the southern half of the North Island.
Antarctica, as evidenced by plant fossils, was subtropical, and supported an environment lush with vegetation. Richard Dawkins
suggests that Antarctica, "provided a clement and ratite-friendly land bridge linking Africa and South America on one side of the world to Australia and New Zealand on the other...".
's North Island (D. novaezealandiae) and South Island (D. robustus); robustus however, comprises three distinct genetic lineages and may eventually be classified as many species, as discussed above.
Although feeding moa were never observed by scientists, their diet has been deduced from fossil
ised contents of their gizzard
s and coprolite
s, as well as indirectly through morphological analysis of skull and beak, and stable isotope analysis
of their bones. Moa fed on a range of plant species and plant parts, including fibrous twigs and leaves taken from low trees and shrubs. The beak of Pachyornis
elephantopus was analogous to a pair of secateurs, and was able to clip the fibrous leaves of New Zealand flax (Phormium tenax) and twigs up to at least 8mm in diameter. Like many other birds, moa swallowed gizzard stones (gastrolith
s), which were retained in their muscular gizzards, providing a grinding action that allowed them to eat coarse plant material. These stones were commonly smooth, rounded quartz pebbles, but stones over 110 millimetres (4 in) in length have been found amongst preserved moa gizzard contents. Dinornis gizzards could often contain several kilograms of stones.
Approximately eight moa trackway
s, with fossilised moa footprint impressions in fluvial silts have been found throughout the North Island, including Waikanae Creek (1872), Napier (1887), Manawatu River (1895), Marton (1896), Palmerston North (1911) (see photograph to right), Ragitikei River (1939), and underwater in Lake Taupo (1973). Analysis of the spacing of these tracks indicate walking speeds of between 3 and 5 km/h (1.75–3 mph).
and a long maturation
period, taking approximately ten years to reach adult size. The large Dinornis species took the same length of time to reach adult size as small moa species, and as a result had accelerated rate of skeletal growth during their juvenile years.
coast. Thirty six whole moa eggs exist in museum collections and vary greatly in size (from 120–240 mm (4.7–9.4 in) in length and 91–178 mm (3.6–7 in) wide). The outer surface of moa eggshell is characterised by small slit-shaped pores. The eggs of most moa species were white, although those of the upland moa (Megalapteryx didinus) were blue-green. A 2010 study by Huynen et al. has found that the eggs of certain species were fragile, only around a millimeter in thickness: "Unexpectedly, several thin-shelled eggs were also shown to belong to the heaviest moa of the genera Dinornis, Euryapteryx and Emeus, making these, to our knowledge, the most fragile of all avian eggs measured to date. Moreover, sex-specific DNA recovered from the outer surfaces of eggshells belonging to species of Dinornis and Euryapteryx suggest that these very thin eggs were likely to have been incubated by the lighter males. The thin nature of the eggshells of these larger species of moa, even if incubated by the male, suggests that egg breakage in these species would have been common if the typical contact method of avian egg incubation was used." Despite the bird's extinction, the high yield of DNA available from recovered fossilized eggs has allowed the moa to have its genome sequenced.
s themselves. Excavations of rock shelters in the eastern North Island during the 1940s uncovered moa nests, which were described as "small depressions obviously scratched out in the soft dry pumice
". Moa nesting material has also been recovered from rock shelters in the Central Otago
region of the South Island, where the dry climate has resulted in the preservation of plant material used to construct the nesting platform (including twigs that have been clipped by moa bills). Seeds
and pollen
within moa coprolites found amongst the nesting material provide evidence that the nesting season was late spring to summer.
of moa were supported by many small rings of bone known as tracheal rings. Excavation of these rings from articulated skeletons has shown that at least two moa genera (Euryapteryx and Emeus) exhibited tracheal elongation, that is, their trachea were up to 1 metre (3 ft) long and formed a large loop within the body cavity. These are the only ratites known to exhibit this feature, which is also present in several other bird groups including swan
s, cranes
and guinea fowl. The feature is associated with deep, resonant vocalisations that can travel long distances.
Several remarkable examples of moa remains have been found that exhibit soft tissues (muscle
, skin
, feathers), preserved through desiccation
when the bird died in a naturally dry site (for example, a cave with a constant dry breeze blowing through it). Most of these specimens have been found in the semi-arid Central Otago
region, the driest part of New Zealand. These include:
Two specimens are known from outside the Central Otago region:
In addition to these specimens, loose moa feathers have been collected from caves and rockshelters in the southern South Island, and so some idea of the moa plumage can be gained. The preserved leg of Megalapteryx didinus from the Old Man Range reveals that this species was feathered right down to the foot. This is likely to have been an adaptation to living in high altitude snowy environments, and is also seen in the Darwin’s Rhea which lives in a similar seasonally snowy habitat. Moa feathers are up to 23 centimetres (9 in) long and a range of colours have been reported, including reddish brown, white, yellowish and purplish. Dark feathers with white or creamy tips have also been found, and indicate that some moa species may have had plumage with a speckled appearance.
The moa's only predator was the massive Haast's Eagle
—until the arrival of human settlers.
The Māori arrived sometime before A.D. 1300, and all moa genera were soon driven to extinction by hunting and, to a lesser extent, forest clearance. By about A.D. 1400 almost all moa are generally thought to have become extinct, along with the Haast's Eagle
which had relied on them for food. Recent research using carbon-14 dating of midden
s strongly suggests that this took less than a hundred years, rather than the period of exploitation lasting several hundred years which had been earlier believed.
Some authors have speculated that a few Megalapteryx didinus may have persisted in remote corners of New Zealand until the 18th and even 19th centuries, but the view is not widely accepted. Some Māori hunters claimed to be in pursuit of the moa as late as the 1770s. Whalers and sealers recalled seeing monstrous birds along the coast of the South Island, and in the 1820s a man named George Pauley made an unverified claim of seeing a moa in the Otago Region of New Zealand. An expedition in the 1850s under Lieutenant A. Impey reported two Emu-like birds on a hillside, on the South Island, and an 1861 story from the Nelson Examiner told of three-toed footprints measuring 36 centimetres (14.2 in) between Takaka and Riwaka
, found by a surveying party, and finally in 1878 the Otago Witness
published an account from a farmer and his shepherd.
Joel Polack
, a trader who lived on the East Coast of the North Island from 1834 to 1837, records in 1838 that he had been shown 'several large fossil ossifications' found near Mt Hikurangi. He was certain that these were the bones of a species of emu or ostrich, noting that 'the Natives add that in times long past they received the traditions that very large birds had existed, but the scarcity of animal food, as well as the easy method of entrapping them, has caused their extermination'. Polack further noted that he had received reports from Māori that a 'species of Struthio' still existed in remote parts of the South Island. Dieffenbach also refers to a fossil from the area near Mt Hikurangi, and surmises that it belongs to 'a bird, now extinct, called Moa (or Movie) by the natives'. In 1839, John W. Harris, a Poverty Bay
flax trader who was a natural history enthusiast, was given a piece of unusual bone by a Māori who had found it in a river bank. He showed the 15 centimetres (6 in) fragment of bone to his uncle, John Rule, a Sydney surgeon, who sent it to Richard Owen
who at that time was working at the Hunterian Museum at the Royal College of Surgeons
in London
. Owen became a noted biologist
, anatomist and paleontologist at the British Museum
.
Owen puzzled over the fragment for almost four years. He established it was part of the femur
of a big animal, but it was uncharacteristically light and honeycombed. Owen announced to a skeptical scientific community and the world that it was from a giant extinct bird like an ostrich
, and named it Dinornis. His deduction was ridiculed in some quarters, but was proved correct with the subsequent discoveries of considerable quantities of moa bones throughout the country, sufficient to reconstruct skeletons of the birds.
In July 2004, the Natural History Museum
in London placed on display the moa bone fragment Owen had first examined, to celebrate 200 years since his birth, and in memory of Owen as founder of the museum.
and Holocene
sedimentary deposits, but are most common in three main types of site:
Bones are commonly found in Caves or ‘tomo’ (Maori word for doline or sinkhole
; often used to refer to pitfalls or vertical cave shafts). The two main ways that the moa bones were deposited in such sites were: 1. Birds that entered the cave to nest or escape bad weather, and subsequently died in the cave; and 2. Birds that fell into a vertical shaft and were unable to escape. Moa bones (and the bones of other extinct birds) have been found in caves throughout New Zealand, especially in the limestone
/marble
areas of northwest Nelson, Karamea
, Waitomo and Te Anau
.
s and concentrate in ‘blowouts
’ between dune ridges. Many such moa bones predate human settlement, although some can originate from Maori midden sites which frequently occur in dunes near harbours and river mouths (for example the large moa hunter sites at Shag River
, Otago
and Wairau Bar
, Marlborough).
in north Canterbury, where bones from at least 183 individual moa have been excavated. Many explanations were proposed to account for how these deposits had formed, ranging from poisonous spring waters to floods and wildfires. However the currently accepted explanation is that the bones accumulated at a slow rate over thousands of years, from birds that had entered the swamps to feed and became trapped in the soft sediment.
The moa is thought to be extinct, but there has been occasional speculation—since at least the late 19th century, and as recently as 1993 and 2008—that some moa may still exist, particularly in the rugged wilderness of South Westland and Fiordland
. Cryptozoologists
and others reputedly continue to search for them, but their claims and supporting evidence (such as of purported footprints or blurry photos) have earned little attention from mainstream experts, and are widely considered pseudoscientific
.
The rediscovery of the takahē
in 1948 after none had been seen since 1898 showed that rare birds may exist undiscovered for a long time. However, the takahē is a much smaller bird than the moa, and was rediscovered after its tracks were identified—yet no reliable evidence of moa tracks has ever been found, and experts still contend that moa survival is extremely unlikely, since this would involve the ground-dwelling birds living unnoticed for over five-hundred years in a region visited often by hunters and hikers.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
(in six genera) of flightless bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s endemic to New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about 3.7 m (12.1 ft) in height with neck outstretched, and weighed about 230 kg (507.1 lb).
Moa are members of the ratite
Ratite
A ratite is any of a diverse group of large, flightless birds of Gondwanan origin, most of them now extinct. Unlike other flightless birds, the ratites have no keel on their sternum—hence the name from the Latin ratis...
group in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Dinornithiformes. The eleven species of moa are the only wingless birds, lacking even the vestigial wings which all other ratite
Ratite
A ratite is any of a diverse group of large, flightless birds of Gondwanan origin, most of them now extinct. Unlike other flightless birds, the ratites have no keel on their sternum—hence the name from the Latin ratis...
s have. They were the dominant herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
s in New Zealand's forest, shrubland and subalpine ecosystems for thousands of years, and until the arrival of the Māori were hunted only by the Haast's Eagle
Haast's Eagle
Haast's Eagle was a species of massive eagles that once lived on the South Island of New Zealand. The species was the largest eagle known to have existed. Its prey consisted mainly of gigantic flightless birds that were unable to defend themselves from the striking force and speed of these eagles,...
. It is generally considered that most, if not all, species of Moa died out by Maori hunting and habitat decline before European discovery
Age of Discovery
The Age of Discovery, also known as the Age of Exploration and the Great Navigations , was a period in history starting in the early 15th century and continuing into the early 17th century during which Europeans engaged in intensive exploration of the world, establishing direct contacts with...
and settlement.
Taxonomy
Kiwi
Kiwi are flightless birds endemic to New Zealand, in the genus Apteryx and family Apterygidae.At around the size of a domestic chicken, kiwi are by far the smallest living ratites and lay the largest egg in relation to their body size of any species of bird in the world...
were formerly regarded as the closest relatives of the moa, but comparisons of their DNA in a paper published in 2005 suggested moa were more closely related to the Australian emu
Emu
The Emu Dromaius novaehollandiae) is the largest bird native to Australia and the only extant member of the genus Dromaius. It is the second-largest extant bird in the world by height, after its ratite relative, the ostrich. There are three subspecies of Emus in Australia...
and cassowary
Cassowary
The cassowaries are ratites, very large flightless birds in the genus Casuarius native to the tropical forests of New Guinea, nearby islands and northeastern Australia. There are three extant species recognized today...
. However research published in 2010 found that the moa's closest cousins were not the emu and cassowary but smaller terrestrial South American birds called the tinamou
Tinamou
The tinamous are a family comprising 47 species of birds found in Central and South America. One of the most ancient living groups of bird, they are related to the ratites. Generally ground dwelling, they are found in a range of habitats....
s which are able to fly.
Although dozens of species were described in the late 19th century and early 20th century, many were based on partial skeletons and turned out to be synonyms. Currently, eleven species are formally recognised, although recent studies using ancient DNA
Ancient DNA
Ancient DNA is DNA isolated from ancient specimens. It can be also loosely described as any DNA recovered from biological samples that have not been preserved specifically for later DNA analyses...
recovered from bones in museum collections suggest that distinct lineages exist within some of these. One factor that has caused much confusion in moa taxonomy is the intraspecific variation of bone sizes, between glacial and inter-glacial periods (see Bergmann’s rule and Allen’s rule) as well as sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
being evident in several species. Dinornis seems to have had the most pronounced sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, with females being up to 150% as tall and 280% as heavy as males—so much bigger that they were formerly classified as separate species until 2003.
Although moa were traditionally reconstructed in an upright position to create impressive height, analysis of their vertebral articulation indicates that they probably carried their heads forward, in the manner of a kiwi. This would have allowed them to graze on low-level vegetation, while being able to lift their heads and browse trees when necessary.
Ancient DNA
Ancient DNA
Ancient DNA is DNA isolated from ancient specimens. It can be also loosely described as any DNA recovered from biological samples that have not been preserved specifically for later DNA analyses...
analyses have determined that there were a number of cryptic evolutionary lineages in several moa genera. These may eventually be classified as species or subspecies; Megalapteryx benhami (Archey) which is synonymised with M. didinus (Owen) because the bones of both share all essential characters. Size differences can be explained by a north-south cline
Cline
Cline, as spelled, is an Irish surname with historical roots in County Roscommon.People bearing the name include:* Catherine Ann Cline , American historian and author* Edward Cline , American screenwriter and director...
combined with temporal variation such that specimens were larger during the Otiran glacial period (the last ice age in New Zealand). Similar temporal size variation is known for the North Island Pachyornis mappini. Some of the other 'Large' ranges in variation for moa species can probably be explained by similar geographic and temporal factors.
Sometimes, the Dinornithidae are considered to be a full order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
(Dinornithiformes), in which case the subfamilies listed below would be advanced to full family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
status (replacing "-inae" with "-idae").
Thus, the currently recognised genera and species are:
- Family †Dinornithidae - Moa
- Subfamily Megalapteryginae - Megalapteryx Moa
- Genus Megalapteryx
- Upland MoaLesser MegalapteryxThe Lesser Megalapteryx or Upland Moa was a species of ratite bird endemic to New Zealand. Ratites are flightless birds with a sternum without a keel. They also have a distinctive palate...
, Megalapteryx didinus (South Island, New Zealand)
- Upland Moa
- Genus Megalapteryx
- Subfamily Anomalopteryginae - Lesser Moa
- Genus AnomalopteryxAnomalopteryxAnomalopteryx is an extinct bird genus known colloquially as the Lesser moa, Little bush moa. or Bush Moa. It stood more than tall and weighed . It inhabited much of the North Island and small sections of the South Island of New Zealand. Its habitat was lowland conifer, broad-leafed, and beech...
- Bush MoaAnomalopteryxAnomalopteryx is an extinct bird genus known colloquially as the Lesser moa, Little bush moa. or Bush Moa. It stood more than tall and weighed . It inhabited much of the North Island and small sections of the South Island of New Zealand. Its habitat was lowland conifer, broad-leafed, and beech...
, Anomalopteryx didiformis (South Island, New Zealand)
- Bush Moa
- Genus Euryapteryx
- North Island Broad-billed MoaNorth Island Broad-billed MoaEuryapteryx is an extinct genus of moa of the family Dinornithidae, consisting of the following species :* Euryapteryx curtus, North Island Broad-billed Moa, also called Coastal Moa* Euryapteryx geranoides, Stout Legged Moa...
, Euryapteryx curtus (North Island, New Zealand) - Stout-legged MoaStout-legged moaThe Stout-legged Moa is an extinct species of New Zealand birds of the Family Moa. These moa lived on North Island, South Island, and on Stewart Island. Its habitat was the lowlands . It was a ratite and a member of the Struthioniform Order...
, Euryapteryx geranoides (South Island, New Zealand)
- North Island Broad-billed Moa
- Genus EmeusEastern moaThe Eastern Moa, Emeus crassus, is an extinct species of moa. When the first specimens were originally described by Richard Owen, they were placed within the genus Dinornis as three different species, but, was later split off into their own genus, Emeus. E. crassus is currently the only species of...
- Eastern MoaEastern moaThe Eastern Moa, Emeus crassus, is an extinct species of moa. When the first specimens were originally described by Richard Owen, they were placed within the genus Dinornis as three different species, but, was later split off into their own genus, Emeus. E. crassus is currently the only species of...
, Emeus crassus (South Island, New Zealand)
- Eastern Moa
- Genus PachyornisPachyornisPachyornis is an extinct genus of ratites from New Zealand which belonged to the moa family. Like all ratites it was a member of the order Struthioniformes. The Struthioniformes are flightless birds with a sternum without a keel. They also have a distinctive palate. This genus contains 2 species,...
- Heavy-footed MoaHeavy-footed MoaThe Heavy-footed Moa, Pachyornis elephantopus, is a species of Moa from the Family Dinornithidae. This moa was widespread on the South Island only, and its habitat was the lowlands . It was a ratite and a member of the Struthioniformes Order. The Struthioniformes are flightless birds with a...
, Pachyornis elephantopus (South Island, New Zealand) - Mappin's MoaMappin's MoaMappin's Moa, Pachyornis mappini, is a Moa from the family Dinornithidae. This moa was found on the North Island only and like its fellow Pacyornis, its habitat was lowlands . It was a ratite and a member of the Struthioniformes Order. The Struthioniformes are flightless birds with a sternum...
, Pachyornis mappini (North Island, New Zealand) - Crested MoaCrested MoaThe Crested Moa, Pachyornis australis, is a species of Moa from the family Dinornithidae. It is one of the 11 known species of Moa to have existed. Moa are grouped together with Emus, Ostriches, Kiwis, Cassowaries, and Rheas in the Ratite group...
, Pachyornis australis (South Island, New Zealand) - Pachyornis new lineage A (North Island, New Zealand)
- Pachyornis new lineage B (South Island, New Zealand)
- Heavy-footed Moa
- Genus Anomalopteryx
- Subfamily Dinornithinae - Giant Moa
- Genus DinornisGiant moaThe giant moa is an extinct genus of ratite birds belonging to the moa family. Like all ratites it was a member of the order Struthioniformes. The Struthioniformes are flightless birds with a sternum without a keel. They also have a distinctive palate...
- Dinornis struthoidesDinornis struthoidesDinornis struthoides is a member of the Moa family. It was a ratite and a member of the Struthioniformes Order. The Struthioniformes are flightless birds with a sternum without a keel. They also have a distinctive palate...
(South Island, New Zealand) - North Island Giant MoaNorth Island Giant MoaThe North Island Giant Moa is one of three extinct moa in the genus Dinornis. It is a ratite and a member of the Struthioniformes Order. The Struthioniformes are flightless birds with a sternum without a keel. They also have a distinctive palate...
, Dinornis novaezealandiae (North Island, New Zealand) - South Island Giant MoaSouth Island Giant MoaThe South Island Giant Moa, Dinornis giganteus is a member of the Moa family. It was a ratite and a member of the Struthioniformes Order. The Struthioniformes are flightless birds with a sternum without a keel. They also have a distinctive palate...
, Dinornis giganteus (South Island, New Zealand) - Dinornis new lineage A (South Island, New Zealand)
- Dinornis new lineage B (South Island, New Zealand)
- Dinornis struthoides
- Genus Dinornis
- Subfamily Megalapteryginae - Megalapteryx Moa
Regional faunas
Analyses of fossil moa bone assemblages have provided detailed data on the habitat preferences of individual moa species, and revealed distinctive regional moa faunas:South Island
The two main faunas identified in the South Island include: 1. The fauna of the high rainfall west coast beech (NothofagusNothofagus
Nothofagus, also known as the southern beeches, is a genus of 35 species of trees and shrubs native to the temperate oceanic to tropical Southern Hemisphere in southern South America and Australasia...
) forests that included Anomalopteryx didiformis and Dinornis giganteus; and 2. The fauna of the dry rainshadow forest and shrublands east of the Southern Alps
Southern Alps
The Southern Alps is a mountain range extending along much of the length of New Zealand's South Island, reaching its greatest elevations near the island's western side...
that included Pachyornis elephantopus, Euryapteryx gravis, Emeus crassus and Dinornis robustus. The two other moa species that existed in the South Island; Pachyornis australis and Megalapteryx didinus might be included in a ‘subalpine
Subalpine
The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.Trees in the...
fauna’, along with the widespread Dinornis robustus. P. australis is the rarest of the moa species, and the only one yet to have been found in Maori middens. Its bones have been found in caves in the northwest Nelson
Nelson, New Zealand
Nelson is a city on the eastern shores of Tasman Bay, and is the economic and cultural centre of the Nelson-Tasman region. Established in 1841, it is the second oldest settled city in New Zealand and the oldest in the South Island....
and Karamea
Karamea
Karamea is a town on the West Coast of the South Island of New Zealand.It is the northernmost settlement of any real size on the West Coast, and is located 96 kilometres north-east by road from Westport. There is no other connecting road to the town - the road north ends at the Kohaihai River some...
districts (such as Honeycomb Hill Cave
Honeycomb Hill Cave
Honeycomb Hill Cave is in the South Island of New Zealand.The Oparara River flows though a section of the cave.The cave was discovered in 1976 by the Buller Caving Group. Since then, 14km of passages have been mapped, and several important deposits of moa bones have been discovered in the caves...
), and some sites around the Wanaka
Wanaka
Wanaka is a town in the Otago region of the South Island of New Zealand. It is situated at the southern end of Lake Wanaka, adjacent to the outflow of the lake to the Clutha River. It is the gateway to Mount Aspiring National Park. Wanaka is primarily a resort town but has both summer and winter...
district. M. didinus is more widespread. Its name ‘upland moa’ reflects the fact its bones are commonly found in the subalpine zone. However, it also occurred down to sea level where there was suitable steep and rocky terrain (such as Punakaiki
Punakaiki
Punakaiki is a small community on the West Coast of the South Island of New Zealand, between Westport and Greymouth. The community lies on the edge of the Paparoa National Park....
on the west coast and Central Otago
Central Otago
Central Otago is the inland part of the New Zealand region of Otago in the South Island. The area commonly known as Central Otago includes both the Central Otago District and the Queenstown-Lakes District to the west....
).
North Island
Significantly less is known about North Island paleofaunas, due to a paucity of fossil sites compared to the South Island; however, the basic pattern of moa-habitat relationships were the same. Although the South Island and the North Island shared some moa species (Euryapteryx gravis, Anomalopteryx didiformis), most were exclusive to one island, reflecting divergence over several thousand years since lower sea level had resulted in a land bridge across Cook StraitCook Strait
Cook Strait is the strait between the North and South Islands of New Zealand. It connects the Tasman Sea on the west with the South Pacific Ocean on the east....
. In the North Island, Dinornis novaezealandiae and Anomalopteryx didiformis dominated in high rainfall forest habitat; a similar pattern to the South Island. The other moa species present in the North Island (Euryapteryx gravis, E. curtus, and Pachyornis geranoides) tended to inhabit drier forest and shrubland habitats. P. geranoides occurred throughout the North Island, while the distributions of E. gravis and E. curtus were almost mutually exclusive, the former having only been found in coastal sites around the southern half of the North Island.
Biology
Evolution
Because moa are a group of flightless birds with no vestiges of wing bones, questions have been raised about how they arrived in New Zealand, and from where. It is suggested that ancestral moa were already in New Zealand as it broke away from Antarctica 70 million years ago. CretaceousCretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Antarctica, as evidenced by plant fossils, was subtropical, and supported an environment lush with vegetation. Richard Dawkins
Richard Dawkins
Clinton Richard Dawkins, FRS, FRSL , known as Richard Dawkins, is a British ethologist, evolutionary biologist and author...
suggests that Antarctica, "provided a clement and ratite-friendly land bridge linking Africa and South America on one side of the world to Australia and New Zealand on the other...".
Sexual dimorphism
It has been long suspected that the pairs of species of moa described as Euryapteryx curtus/E. exilis, Emeus huttonii/E. crassus, and Pachyornis septentrionalis/P. mappini constituted males and females, respectively. This has been confirmed by analysis for sex-specific genetic markers of DNA extracted from bone material. For example, prior to 2003 there were three species of Dinornis recognised: South Island giant moa (D. giganteus), North Island giant moa (D. novaezealandiae) and slender moa (D. struthioides). However, DNA showed that all D. struthioides were in fact males, and all D. giganteus were females. Therefore the three species of Dinornis were reclassified as two species, one each formerly occurring on New ZealandNew Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
's North Island (D. novaezealandiae) and South Island (D. robustus); robustus however, comprises three distinct genetic lineages and may eventually be classified as many species, as discussed above.
Diet
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
ised contents of their gizzard
Gizzard
The gizzard, also referred to as the ventriculus, gastric mill, and gigerium, is an organ found in the digestive tract of some animals, including birds, reptiles, earthworms and some fish. This specialized stomach constructed of thick, muscular walls is used for grinding up food; often rocks are...
s and coprolite
Coprolite
A coprolite is fossilized animal dung. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour rather than morphology. The name is derived from the Greek words κοπρος / kopros meaning 'dung' and λιθος / lithos meaning 'stone'. They...
s, as well as indirectly through morphological analysis of skull and beak, and stable isotope analysis
Isotope analysis
Isotope analysis is the identification of isotopic signature, the distribution of certain stable isotopes and chemical elements within chemical compounds. This can be applied to a food web to make it possible to draw direct inferences regarding diet, trophic level, and subsistence...
of their bones. Moa fed on a range of plant species and plant parts, including fibrous twigs and leaves taken from low trees and shrubs. The beak of Pachyornis
Pachyornis
Pachyornis is an extinct genus of ratites from New Zealand which belonged to the moa family. Like all ratites it was a member of the order Struthioniformes. The Struthioniformes are flightless birds with a sternum without a keel. They also have a distinctive palate. This genus contains 2 species,...
elephantopus was analogous to a pair of secateurs, and was able to clip the fibrous leaves of New Zealand flax (Phormium tenax) and twigs up to at least 8mm in diameter. Like many other birds, moa swallowed gizzard stones (gastrolith
Gastrolith
A gastrolith, also called a stomach stone or gizzard stones, is a rock held inside a gastrointestinal tract. Gastroliths are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. The grain size depends upon the size of the animal and the gastrolith's...
s), which were retained in their muscular gizzards, providing a grinding action that allowed them to eat coarse plant material. These stones were commonly smooth, rounded quartz pebbles, but stones over 110 millimetres (4 in) in length have been found amongst preserved moa gizzard contents. Dinornis gizzards could often contain several kilograms of stones.
Locomotion
Fossil trackway
A fossil trackway is a type of trace fossil, a trackway made by an organism. Many fossil trackways were made by dinosaurs, early tetrapods, and other quadrupeds and bipeds on land...
s, with fossilised moa footprint impressions in fluvial silts have been found throughout the North Island, including Waikanae Creek (1872), Napier (1887), Manawatu River (1895), Marton (1896), Palmerston North (1911) (see photograph to right), Ragitikei River (1939), and underwater in Lake Taupo (1973). Analysis of the spacing of these tracks indicate walking speeds of between 3 and 5 km/h (1.75–3 mph).
Breeding
Examination of growth rings present in moa cortical bone has revealed that these birds were K-selected, as are many other large endemic New Zealand birds. They are characterised by having low fecundityFecundity
Fecundity, derived from the word fecund, generally refers to the ability to reproduce. In demography, fecundity is the potential reproductive capacity of an individual or population. In biology, the definition is more equivalent to fertility, or the actual reproductive rate of an organism or...
and a long maturation
Maturation
Maturation could refer to any of the following:* Fetal development* Developmental biology* Emotional development* Or physical maturation of any biological life form - see individual articles for maturation of different life forms....
period, taking approximately ten years to reach adult size. The large Dinornis species took the same length of time to reach adult size as small moa species, and as a result had accelerated rate of skeletal growth during their juvenile years.
Eggs
Fragments of moa eggshell are often encountered in archaeological sites and sand dunes around the New ZealandNew Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
coast. Thirty six whole moa eggs exist in museum collections and vary greatly in size (from 120–240 mm (4.7–9.4 in) in length and 91–178 mm (3.6–7 in) wide). The outer surface of moa eggshell is characterised by small slit-shaped pores. The eggs of most moa species were white, although those of the upland moa (Megalapteryx didinus) were blue-green. A 2010 study by Huynen et al. has found that the eggs of certain species were fragile, only around a millimeter in thickness: "Unexpectedly, several thin-shelled eggs were also shown to belong to the heaviest moa of the genera Dinornis, Euryapteryx and Emeus, making these, to our knowledge, the most fragile of all avian eggs measured to date. Moreover, sex-specific DNA recovered from the outer surfaces of eggshells belonging to species of Dinornis and Euryapteryx suggest that these very thin eggs were likely to have been incubated by the lighter males. The thin nature of the eggshells of these larger species of moa, even if incubated by the male, suggests that egg breakage in these species would have been common if the typical contact method of avian egg incubation was used." Despite the bird's extinction, the high yield of DNA available from recovered fossilized eggs has allowed the moa to have its genome sequenced.
Nests
There is no evidence to suggest that moa were colonial nesters. While evidence of moa nesting is often inferred from accumulations of eggshell fragments found in caves and rock shelters, little evidence exists of the nestBird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
s themselves. Excavations of rock shelters in the eastern North Island during the 1940s uncovered moa nests, which were described as "small depressions obviously scratched out in the soft dry pumice
Pumice
Pumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...
". Moa nesting material has also been recovered from rock shelters in the Central Otago
Central Otago
Central Otago is the inland part of the New Zealand region of Otago in the South Island. The area commonly known as Central Otago includes both the Central Otago District and the Queenstown-Lakes District to the west....
region of the South Island, where the dry climate has resulted in the preservation of plant material used to construct the nesting platform (including twigs that have been clipped by moa bills). Seeds
SEEDS
SEEDS is a voluntary organisation registered under the Societies Act of India....
and pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
within moa coprolites found amongst the nesting material provide evidence that the nesting season was late spring to summer.
Vocalisation
Although there is no surviving record of what sounds moa made, some idea of their calls can be gained from fossil evidence. The tracheaVertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...
of moa were supported by many small rings of bone known as tracheal rings. Excavation of these rings from articulated skeletons has shown that at least two moa genera (Euryapteryx and Emeus) exhibited tracheal elongation, that is, their trachea were up to 1 metre (3 ft) long and formed a large loop within the body cavity. These are the only ratites known to exhibit this feature, which is also present in several other bird groups including swan
Swan
Swans, genus Cygnus, are birds of the family Anatidae, which also includes geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometimes, they are considered a distinct subfamily, Cygninae...
s, cranes
Crane (bird)
Cranes are a family, Gruidae, of large, long-legged and long-necked birds in the order Gruiformes. There are fifteen species of crane in four genera. Unlike the similar-looking but unrelated herons, cranes fly with necks outstretched, not pulled back...
and guinea fowl. The feature is associated with deep, resonant vocalisations that can travel long distances.
Feathers and soft tissues
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
, skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
, feathers), preserved through desiccation
Desiccation
Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic substance that induces or sustains such a state in its local vicinity in a moderately sealed container.-Science:...
when the bird died in a naturally dry site (for example, a cave with a constant dry breeze blowing through it). Most of these specimens have been found in the semi-arid Central Otago
Central Otago
Central Otago is the inland part of the New Zealand region of Otago in the South Island. The area commonly known as Central Otago includes both the Central Otago District and the Queenstown-Lakes District to the west....
region, the driest part of New Zealand. These include:
- Dried muscle on bones of a female Dinornis robustus found at Tiger Hill in the Manuherikia RiverManuherikia RiverThe Manuherikia River is located in Otago in the South Island of New Zealand. It rises in the far north of the Maniototo, flowing southwest for 85 kilometres before its confluence with the Clutha River at Alexandra. During the 1860s the Manuherikia was one of the centres of the Central Otago Gold...
Valley by gold miners in 1864 (currently held by Yorkshire MuseumYorkshire MuseumThe Yorkshire Museum is a museum in York, England. It is the home of the Cawood sword, and has four permanent collections, covering biology, geology, archaeology and astronomy...
) - Several bones of Emeus crassus with muscle attached, and a row of neck vertebrae with muscle, skin and feathers collected from Earnscleugh Cave near the town of Alexandra in 1870 (currently held by Otago MuseumOtago museumThe Otago Museum is situated in Dunedin, New Zealand. It was founded in 1868 and has a collection of over two million artefacts and specimens from the fields of natural history and ethnography...
) - An articulated foot of a male Dinornis robustus with skin and foot pads preserved found in a crevice on the Knobby Range in 1874 (currently held by Otago MuseumOtago museumThe Otago Museum is situated in Dunedin, New Zealand. It was founded in 1868 and has a collection of over two million artefacts and specimens from the fields of natural history and ethnography...
) - The type specimen of Megalapteryx didinus found near QueenstownQueenstown, New ZealandQueenstown is a resort town in Otago in the south-west of New Zealand's South Island. It is built around an inlet called Queenstown Bay on Lake Wakatipu, a long thin Z-shaped lake formed by glacial processes, and has spectacular views of nearby mountains....
in 1878 (currently held by Natural History MuseumNatural History MuseumThe Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...
, London; see photograph of foot on this page) - The lower leg of Pachyornis elephantopus with skin and muscle from the Hector Range in 1884; (currently held by the Zoology Department, Cambridge University)
- The complete feathered leg of a Megalapteryx didinus from Old Man Range in 1894 (currently held by Otago MuseumOtago museumThe Otago Museum is situated in Dunedin, New Zealand. It was founded in 1868 and has a collection of over two million artefacts and specimens from the fields of natural history and ethnography...
) - The head of a Megalapteryx didinus found near Cromwell sometime prior to 1949 (currently held by the Museum of New Zealand).
Two specimens are known from outside the Central Otago region:
- A complete foot of Megalapteryx didinus found in a cave on Mount OwenMount OwenMount Owen can refer to:*Mount Owen, New Zealand*Mount Owen, California, former name of Brown, California*Mount Owen in the Bow Range of the Canadian Rockies*Mount Owen *Mount Owen in the Ruby Range of Colorado, USA...
near Nelson in 1980s (currently held by the Museum of New Zealand) - A skeleton of Anomalopteryx didiformis with muscle, skin and feather bases collected from a cave near Te AnauTe AnauTe Anau is a town in the South Island of New Zealand. It is on the eastern shore of Lake Te Anau in Fiordland. Lake Te Anau is the largest lake in the South Island and second only within New Zealand to Lake Taupo. The 2001 census recorded the town's population as 1,857...
in 1980.
In addition to these specimens, loose moa feathers have been collected from caves and rockshelters in the southern South Island, and so some idea of the moa plumage can be gained. The preserved leg of Megalapteryx didinus from the Old Man Range reveals that this species was feathered right down to the foot. This is likely to have been an adaptation to living in high altitude snowy environments, and is also seen in the Darwin’s Rhea which lives in a similar seasonally snowy habitat. Moa feathers are up to 23 centimetres (9 in) long and a range of colours have been reported, including reddish brown, white, yellowish and purplish. Dark feathers with white or creamy tips have also been found, and indicate that some moa species may have had plumage with a speckled appearance.
Extinction
Haast's Eagle
Haast's Eagle was a species of massive eagles that once lived on the South Island of New Zealand. The species was the largest eagle known to have existed. Its prey consisted mainly of gigantic flightless birds that were unable to defend themselves from the striking force and speed of these eagles,...
—until the arrival of human settlers.
The Māori arrived sometime before A.D. 1300, and all moa genera were soon driven to extinction by hunting and, to a lesser extent, forest clearance. By about A.D. 1400 almost all moa are generally thought to have become extinct, along with the Haast's Eagle
Haast's Eagle
Haast's Eagle was a species of massive eagles that once lived on the South Island of New Zealand. The species was the largest eagle known to have existed. Its prey consisted mainly of gigantic flightless birds that were unable to defend themselves from the striking force and speed of these eagles,...
which had relied on them for food. Recent research using carbon-14 dating of midden
Midden
A midden, is an old dump for domestic waste which may consist of animal bone, human excrement, botanical material, vermin, shells, sherds, lithics , and other artifacts and ecofacts associated with past human occupation...
s strongly suggests that this took less than a hundred years, rather than the period of exploitation lasting several hundred years which had been earlier believed.
Some authors have speculated that a few Megalapteryx didinus may have persisted in remote corners of New Zealand until the 18th and even 19th centuries, but the view is not widely accepted. Some Māori hunters claimed to be in pursuit of the moa as late as the 1770s. Whalers and sealers recalled seeing monstrous birds along the coast of the South Island, and in the 1820s a man named George Pauley made an unverified claim of seeing a moa in the Otago Region of New Zealand. An expedition in the 1850s under Lieutenant A. Impey reported two Emu-like birds on a hillside, on the South Island, and an 1861 story from the Nelson Examiner told of three-toed footprints measuring 36 centimetres (14.2 in) between Takaka and Riwaka
Riwaka
Riwaka is a small town in the north of New Zealand's South Island. It lies beside Tasman Bay, five kilometres north of Motueka, and close to the mouth of the Riwaka River....
, found by a surveying party, and finally in 1878 the Otago Witness
Otago Witness
The Otago Witness was a prominent newspaper in the early years of the European settlement of New Zealand, produced in Dunedin, the provincial capital of Otago. Inaugurated in 1851, three years after the founding of the city, the Witness was originally a four-page fortnightly paper, becoming a...
published an account from a farmer and his shepherd.
Discovery by science
Joel Samuel Polack
Joel Samuel Polack was one of the first Jewish settlers in New Zealand, arriving in 1831. He is regarded as an authority on pre-colonial New Zealand and his two books are often cited.-Early life:...
, a trader who lived on the East Coast of the North Island from 1834 to 1837, records in 1838 that he had been shown 'several large fossil ossifications' found near Mt Hikurangi. He was certain that these were the bones of a species of emu or ostrich, noting that 'the Natives add that in times long past they received the traditions that very large birds had existed, but the scarcity of animal food, as well as the easy method of entrapping them, has caused their extermination'. Polack further noted that he had received reports from Māori that a 'species of Struthio' still existed in remote parts of the South Island. Dieffenbach also refers to a fossil from the area near Mt Hikurangi, and surmises that it belongs to 'a bird, now extinct, called Moa (or Movie) by the natives'. In 1839, John W. Harris, a Poverty Bay
Poverty Bay
Poverty Bay is the largest of several small bays on the east coast of New Zealand's North Island to the north of Hawkes Bay. It stretches for 10 kilometres from Young Nick's Head in the southwest to Tuaheni Point in the northeast. The city of Gisborne is located on the northern shore of the bay...
flax trader who was a natural history enthusiast, was given a piece of unusual bone by a Māori who had found it in a river bank. He showed the 15 centimetres (6 in) fragment of bone to his uncle, John Rule, a Sydney surgeon, who sent it to Richard Owen
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
who at that time was working at the Hunterian Museum at the Royal College of Surgeons
Royal College of Surgeons of England
The Royal College of Surgeons of England is an independent professional body and registered charity committed to promoting and advancing the highest standards of surgical care for patients, regulating surgery, including dentistry, in England and Wales...
in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
. Owen became a noted biologist
Biologist
A biologist is a scientist devoted to and producing results in biology through the study of life. Typically biologists study organisms and their relationship to their environment. Biologists involved in basic research attempt to discover underlying mechanisms that govern how organisms work...
, anatomist and paleontologist at the British Museum
British Museum
The British Museum is a museum of human history and culture in London. Its collections, which number more than seven million objects, are amongst the largest and most comprehensive in the world and originate from all continents, illustrating and documenting the story of human culture from its...
.
Owen puzzled over the fragment for almost four years. He established it was part of the femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
of a big animal, but it was uncharacteristically light and honeycombed. Owen announced to a skeptical scientific community and the world that it was from a giant extinct bird like an ostrich
Ostrich
The Ostrich is one or two species of large flightless birds native to Africa, the only living member of the genus Struthio. Some analyses indicate that the Somali Ostrich may be better considered a full species apart from the Common Ostrich, but most taxonomists consider it to be a...
, and named it Dinornis. His deduction was ridiculed in some quarters, but was proved correct with the subsequent discoveries of considerable quantities of moa bones throughout the country, sufficient to reconstruct skeletons of the birds.
In July 2004, the Natural History Museum
Natural History Museum
The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...
in London placed on display the moa bone fragment Owen had first examined, to celebrate 200 years since his birth, and in memory of Owen as founder of the museum.
Moa bone deposits
Since the discovery of the first moa bones in the late 1830s, thousands more have been found. They occur in a range of late QuaternaryQuaternary
The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...
and Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
sedimentary deposits, but are most common in three main types of site:
Caves
Sinkhole
A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the Earth's surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone...
; often used to refer to pitfalls or vertical cave shafts). The two main ways that the moa bones were deposited in such sites were: 1. Birds that entered the cave to nest or escape bad weather, and subsequently died in the cave; and 2. Birds that fell into a vertical shaft and were unable to escape. Moa bones (and the bones of other extinct birds) have been found in caves throughout New Zealand, especially in the limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
/marble
Marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...
areas of northwest Nelson, Karamea
Karamea
Karamea is a town on the West Coast of the South Island of New Zealand.It is the northernmost settlement of any real size on the West Coast, and is located 96 kilometres north-east by road from Westport. There is no other connecting road to the town - the road north ends at the Kohaihai River some...
, Waitomo and Te Anau
Te Anau
Te Anau is a town in the South Island of New Zealand. It is on the eastern shore of Lake Te Anau in Fiordland. Lake Te Anau is the largest lake in the South Island and second only within New Zealand to Lake Taupo. The 2001 census recorded the town's population as 1,857...
.
Dunes
Moa bones and eggshell fragments sometimes occur in active coastal sand dunes, where they may erode from paleosolPaleosol
In the geosciences, paleosol can have two meanings. The first meaning, common in geology and paleontology, refers to a former soil preserved by burial underneath either sediments or volcanic deposits , which in the case of older deposits have lithified into rock...
s and concentrate in ‘blowouts
Blowout (geology)
Blowouts are sandy depressions in a sand dune ecosystem caused by the removal of sediments by wind.Blowouts occur in partially vegetated dunefields or sandhills. A blowout forms when a patch of protective vegetation is lost, allowing strong winds to "blow out" sand and form a depression...
’ between dune ridges. Many such moa bones predate human settlement, although some can originate from Maori midden sites which frequently occur in dunes near harbours and river mouths (for example the large moa hunter sites at Shag River
Shag River
Shag River is located in Otago in the South Island of New Zealand. It rises in the Kakanui Range, flowing southeast for 50 kilometres before reaching the Pacific Ocean near the town of Palmerston...
, Otago
Otago
Otago is a region of New Zealand in the south of the South Island. The region covers an area of approximately making it the country's second largest region. The population of Otago is...
and Wairau Bar
Wairau Bar
The Wairau Bar, or Te Pokohiwi, is a 19 ha gravel bar formed where the Wairau River meets the sea in Cloudy Bay, Marlborough, north-eastern South Island, New Zealand. It is an important archaeological site, apparently settled within one or two generations of the arrival of Polynesians in New...
, Marlborough).
Swamps/mirings
Densely intermingled moa bones have been encountered in swamps throughout New Zealand. The most well-known example is at Pyramid ValleyPyramid Valley
Pyramid Valley is a limestone rock formation near Waikari in the North Canterbury region of New Zealand. It lies 80 km north-west of Christchurch. On the foot of the valley is a swamp which became notable in 1939 as New Zealand's largest paleontological site for moa fossils...
in north Canterbury, where bones from at least 183 individual moa have been excavated. Many explanations were proposed to account for how these deposits had formed, ranging from poisonous spring waters to floods and wildfires. However the currently accepted explanation is that the bones accumulated at a slow rate over thousands of years, from birds that had entered the swamps to feed and became trapped in the soft sediment.
Claims of moa survival
Fiordland
Fiordland is a geographic region of New Zealand that is situated on the south-western corner of the South Island, comprising the western-most third of Southland. Most of Fiordland is dominated by the steep sides of the snow-capped Southern Alps, deep lakes and its ocean-flooded, steep western valleys...
. Cryptozoologists
Cryptozoology
Cryptozoology refers to the search for animals whose existence has not been proven...
and others reputedly continue to search for them, but their claims and supporting evidence (such as of purported footprints or blurry photos) have earned little attention from mainstream experts, and are widely considered pseudoscientific
Pseudoscience
Pseudoscience is a claim, belief, or practice which is presented as scientific, but which does not adhere to a valid scientific method, lacks supporting evidence or plausibility, cannot be reliably tested, or otherwise lacks scientific status...
.
The rediscovery of the takahē
Takahe
The Takahē or South Island Takahē, Porphyrio hochstetteri is a flightless bird indigenous to New Zealand and belonging to the rail family. It was thought to be extinct after the last four known specimens were taken in 1898...
in 1948 after none had been seen since 1898 showed that rare birds may exist undiscovered for a long time. However, the takahē is a much smaller bird than the moa, and was rediscovered after its tracks were identified—yet no reliable evidence of moa tracks has ever been found, and experts still contend that moa survival is extremely unlikely, since this would involve the ground-dwelling birds living unnoticed for over five-hundred years in a region visited often by hunters and hikers.
See also
- List of extinct New Zealand animals (birds)
- Late Quaternary prehistoric birdsLate Quaternary prehistoric birdsPrehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...
- Island gigantismIsland gigantismIsland gigantism or insular giantism is a biological phenomenon in which the size of animals isolated on an island increases dramatically in comparison to their mainland relatives....
- Moa-naloMoa-naloThe moa-nalo are a group of extinct aberrant, goose-like ducks that lived on the larger Hawaiian Islands, except Hawaii itself, in the Pacific...
, an extinct gigantic goose-like duck from the Hawaiian Islands. - MegafaunaMegafaunaIn terrestrial zoology, megafauna are "giant", "very large" or "large" animals. The most common thresholds used are or...
External links
- TerraNature list of New Zealand's extinct birds
- Moa Pages
- TerraNature page on Moa
- Tree of Life classification and references
- Moa in Te Ara - the Encyclopedia of New Zealand