Cave Bear
Encyclopedia
The cave bear was a species
of bear
that lived in Europe
during the Pleistocene
and became extinct at the beginning of the Last Glacial Maximum
about 27,500 years ago.
Both the name cave and the scientific name spelaeus derive from the fact that fossils of this species were mostly found in caves, indicating that this species spent more time in caves than the brown bear
, which only uses caves for hibernation
. Consequently, in the course of time, whole layers of bones, almost entirely those of skeletons, were found in many caves.
s, unicorn
s, apes, canids or felids, Esper postulated that they actually belonged to polar bear
s. Twenty years later, Johann Christian Rosenmüller
, an anatomist at the Leipzig University, gave the species its binomial name. The bones were so numerous that most researchers held little respect for them. During World War I
, large amounts of cave bear bones were used as a source of phosphate
s, leaving behind little more than skulls and leg bones.
Many caves in Central Europe
have skeletons of cave bears inside, for example the Heinrichshöhle in Hemer or the Dechenhöhle in Iserlohn
, Germany
. In Romania
, there is a cave called Bears' Cave where 140 cave bear skeletons were discovered in 1983.
to Eurasia
, from Italy
and Greece
to Belgium
, the Netherlands
and Great Britain
, across a portion of Germany
through Poland
, then south into Hungary
, Romania
and parts of Russia
, Caucasus
and northern Iran
. There have been no traces of cave bears living in northern Britain, Scandinavia
or the Baltic countries
, which were covered in extensive glacier
s at the time. The largest numbers of cave bear remains have been found in Austria
, Switzerland
, southern Germany, northern Italy, northern Spain, Croatia
, Hungary, and Romania. The huge number of bones found in south, central and east Europe has led some scientists to think that Europe may have once had literal herds of cave bears. Some however point out that though some caves have thousands of bones, they were accumulated over a period of 100,000 years or more, thus requiring only two deaths in a cave per year to account for the large numbers.
The cave bear inhabited low mountainous areas, especially in regions rich in limestone
caves. They seem to have avoided open plains, preferring forested or forest-edged terrains.
lacked the usual 2–3 premolars present in other bears; to compensate, the last molar is very elongated, with supplementary cusps. The humerus
of the cave bear was similar in size to that of the polar bear
, as were the femora of females. The femora of male cave bears, however, bore more similarities in size to those of kodiak bear
s.
The morphological features of the cave bear chewing apparatus, including loss of premolars, have long been suggested to indicate that their diets displayed a higher degree of herbivory than the Eurasian brown bear
. Indeed, a solely vegetarian diet has been inferred on the basis of tooth morphology. Results obtained on the stable isotopes of cave bear bones also point to a largely vegetarian diet in having low levels of nitrogen-15 and carbon-13
, which are accumulated at a faster rate by meat eaters as opposed to herbivores.
However, some evidence points toward inclusion of at least occasional animal protein in the cave bear diet. For example, toothmarks on cave bear remains in areas where cave bears are the only recorded potential carnivore
s suggests occasional cannibalistic scavenging, possibly on individuals that died during hibernation, and dental microwear analysis indicates that the cave bear may have fed on a greater quantity of bone than its contemporary, the smaller Eurasian brown bear. Additionally, cave bear remains from Peştera cu Oase
in the southwestern tip of the Carpathian mountains
had elevated levels of nitrogen-15 in their bones, indicative of an omnivorous
diet, although the values are within the range of those found for the strictly herbivorous mammoth
.
Although the current prevailing opinion concludes that cave bears were largely herbivorous, and more so than any modern species of the genus Ursus
, increasing evidence points to an omnivorous diet, based both on regional variability of isotopic composition of bone remains indicative of dietary plasticity, and on a recent reevaluation of its craniodental morphology that places the cave bear squarely among omnivorous modern bear species with respect to its skull and tooth shapes.
Death during hibernation was a common end for cave bears, mainly befalling specimens that failed ecologically during the summer season through inexperience, sickness or old age. Some cave bear bones show signs of numerous different ailments, including fusion of the spine, bone tumours, cavities
, tooth resorption
, necrosis
(particularly in younger specimens), osteomyelitis
, periostitis
, rickets
and kidney stones. Male cave bear skeletons have been found with broken baculum
s, probably due to fighting during breeding season. Cave bear longevity
is unknown, though it has been estimated that they seldom exceeded 20 years of age. Paleontologists doubt adult cave bears had any natural predators, save for pack hunting wolves and cave hyena
s which would probably have attacked sick or infirm specimens. Cave hyenas are thought to be responsible for the dis-articulation and destruction of some cave bear skeletons. Such large carcasses were an optimal food resource for the hyenas, especially at the end of the winter, when food was scarce. The presence of fully articulated adult cave lion
skeletons, deep in cave bear dens, indicates that lions may have occasionally entered dens to prey on hibernating cave bears, with some dying in the attempt.
-Pleistocene
Etruscan bear (Ursus etruscus
) that lived ~5.3 Mya to 10,000 years ago. The last common ancestor of cave bears and brown bears lived between 1.2 and 1.4 million years ago. The immediate precursor of the cave bear was probably Ursus deningeri
(Deninger's bear), a species restricted to Pleistocene
Europe ~1.8 Mya to 100,000 years ago. The transition between Deninger's bear and the cave bear is given as the last Interglacial, although the boundary between these forms is arbitrary and intermediate or transitional taxa have been proposed, e.g. Ursus spelaeus deningeroides, while other authorities consider both taxa to be chronological variants of the same species.
Cave bears found in different regions vary in age, thus facilitating investigations into evolutionary trends. The three anterior premolar
s were gradually reduced, then disappeared, possibly in response to a largely vegetarian diet. In a fourth of the skulls found in the Conturines, the third premolar is still present, while more derived
specimens elsewhere lack it. The last remaining premolar became conjugated with the true molars
, enlarging the crown and granting it more cusps and cutting borders. This phenomenon known as molarization improved the mastication
capacities of the molars, facilitating the processing of tough vegetation. This allowed the cave bear to gain more energy for hibernation while eating less than its ancestors.
succeeded in recovering and sequencing
nuclear DNA
of a cave bear that lived between 42,000 and 44,000 years ago. The procedure used genomic DNA extracted from the animal's tooth
. Sequencing the DNA directly (rather than first replicating it with the polymerase chain reaction
), the scientists were able to recover 21 cave bear gene
s from remains that did not yield significant amounts of DNA with traditional techniques. This study confirmed and built on results from a previous study using mitochondrial DNA
extracted from cave bear remains ranging from 20,000 to 130,000 years old. Both show the cave bear to be more closely related to the brown bear
and polar bear
than the American black bear
, but having split from the brown bear lineage prior to the diversification of distinct eastern and western brown bear lineages and prior to the split of brown bears and polar bears. The divergence
date estimate of cave bears and brown bears is ~1.2–1.4 Mya.
Compared with other megafauna
l species that also became extinct during the last Glacial Maximum, the cave bear was believed to have had a more specialized diet of high-quality plants and a relatively restricted geographical range. This was suggested as an explanation as to why it died out so much earlier than the rest. Some experts have disputed this claim as the cave bear had survived multiple climate changes prior to extinction. Additionally, mitochondrial DNA
research indicated that the genetic decline of the cave bear began long before it went extinct, demonstrating that habitat loss due to climate change was not responsible. Finally, high δ15N levels were found in cave bear bones from Romania
, indicating wider dietary possibilities than previously believed.
Overhunting by human
s has been largely dismissed because human populations at the time were too small to pose a serious threat to the cave bear's survival, though there is evidence that the two species may have competed for living space in caves. Unlike brown bears, cave bears are seldom represented in cave paintings, leading some experts to believe that the cave bear may have been avoided by human hunters or their habitat preferences may not have overlapped. The late paleontologist Bjorn Kurten
hypothesized
that cave bear populations were fragmented and under stress even before the advent of the glaciers. It is possible that populations living south of the Alps
survived significantly longer.
There is some evidence that the cave bear only used caves for hibernation and was not inclined to use other locations, such as thicket
s, for this purpose, in contrast to the more versatile brown bear
. This specialized hibernation behavior would have caused a high winter mortality rate for cave bears that failed to find available caves. Therefore, as human populations slowly increased, the cave bear faced a shrinking pool of suitable caves, and slowly faded away to extinction, as both Neanderthals and anatomically modern humans sought out caves as living quarters, depriving the cave bear of vital habitat. This hypothesis is being researched at this time.
s may have worship
ped cave bears, especially at Drachenloch, in Switzerland, where a stone chest was discovered with a number of bear skulls stacked upon it. Neanderthals, who also inhabited the entrance of the cave, are believed to have built it. A massive stone slab covered the top of the structure. At the cave entrance, seven bear skulls were arranged with their muzzles facing the cave entrance, while deeper in the cave, a further six bear skulls were lodged in niches along the wall. Next to these remains were bundles of limb bones belonging to different bears. Consequently, it was at this site that the supposed symbol of the "Cult of the Cave Bear" was found. This consisted of the skull of a three-year-old bear pierced in the cheek by the leg-bone of younger bear. The arrangement of these bones of different bears are not believed to have happened by chance.
A similar phenomenon was encountered in Regourdou, southern France. A rectangular pit contained the remains of at least twenty bears, covered by a massive stone slab. The remains of a Neanderthal lay nearby in another stone pit, with various objects, including a bear humerus, a scraper, a core, and some flakes, which were interpreted as grave offerings.
The unusual finding in a deep chamber of Basua Cave in Savona
, Italy, is thought to be related to cave bear worship, as there is a vaguely zoomorphic stalagmite
surrounded by clay pellets. It was apparently used by Neanderthals for a ceremony; the fact that bear bones lay scattered on the floor further suggests that this was likely to have had some sort of ritual purpose.
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...
of bear
Bear
Bears are mammals of the family Ursidae. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern...
that lived in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
during the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
and became extinct at the beginning of the Last Glacial Maximum
Last Glacial Maximum
The Last Glacial Maximum refers to a period in the Earth's climate history when ice sheets were at their maximum extension, between 26,500 and 19,000–20,000 years ago, marking the peak of the last glacial period. During this time, vast ice sheets covered much of North America, northern Europe and...
about 27,500 years ago.
Both the name cave and the scientific name spelaeus derive from the fact that fossils of this species were mostly found in caves, indicating that this species spent more time in caves than the brown bear
Brown Bear
The brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...
, which only uses caves for hibernation
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...
. Consequently, in the course of time, whole layers of bones, almost entirely those of skeletons, were found in many caves.
History of cave bear discoveries
Cave bear skeletons were first described in 1774 by Johann Friederich Esper in his book Newly Discovered Zoolites of Unknown Four Footed Animals. Originally thought to belong to dragonDragon
A dragon is a legendary creature, typically with serpentine or reptilian traits, that feature in the myths of many cultures. There are two distinct cultural traditions of dragons: the European dragon, derived from European folk traditions and ultimately related to Greek and Middle Eastern...
s, unicorn
Unicorn
The unicorn is a legendary animal from European folklore that resembles a white horse with a large, pointed, spiraling horn projecting from its forehead, and sometimes a goat's beard...
s, apes, canids or felids, Esper postulated that they actually belonged to polar bear
Polar Bear
The polar bear is a bear native largely within the Arctic Circle encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the world's largest land carnivore and also the largest bear, together with the omnivorous Kodiak Bear, which is approximately the same size...
s. Twenty years later, Johann Christian Rosenmüller
Johann Christian Rosenmüller
Johann Christian Rosenmüller was a German anatomist born near Hildburghausen, Thuringia. He was the son of theologian Johann Georg Rosenmüller ....
, an anatomist at the Leipzig University, gave the species its binomial name. The bones were so numerous that most researchers held little respect for them. During World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, large amounts of cave bear bones were used as a source of phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
s, leaving behind little more than skulls and leg bones.
Many caves in Central Europe
Central Europe
Central Europe or alternatively Middle Europe is a region of the European continent lying between the variously defined areas of Eastern and Western Europe...
have skeletons of cave bears inside, for example the Heinrichshöhle in Hemer or the Dechenhöhle in Iserlohn
Iserlohn
Iserlohn is a city in the Märkischer Kreis district, in North Rhine-Westphalia, Germany. It is the largest city by population and area within the district and the Sauerland region.-Geography:...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
. In Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
, there is a cave called Bears' Cave where 140 cave bear skeletons were discovered in 1983.
Range and habitat
The cave bear's range stretched across Europe, from SpainSpain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
to Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
, from Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
and Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
to Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
, the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
and Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
, across a portion of Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
through Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
, then south into Hungary
Hungary
Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...
, Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
and parts of Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, Caucasus
Caucasus
The Caucasus, also Caucas or Caucasia , is a geopolitical region at the border of Europe and Asia, and situated between the Black and the Caspian sea...
and northern Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...
. There have been no traces of cave bears living in northern Britain, Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
or the Baltic countries
Baltic countries
The term Baltic states refers to the Baltic territories which gained independence from the Russian Empire in the wake of World War I: primarily the contiguous trio of Estonia, Latvia, Lithuania ; Finland also fell within the scope of the term after initially gaining independence in the 1920s.The...
, which were covered in extensive glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
s at the time. The largest numbers of cave bear remains have been found in Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
, Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
, southern Germany, northern Italy, northern Spain, Croatia
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...
, Hungary, and Romania. The huge number of bones found in south, central and east Europe has led some scientists to think that Europe may have once had literal herds of cave bears. Some however point out that though some caves have thousands of bones, they were accumulated over a period of 100,000 years or more, thus requiring only two deaths in a cave per year to account for the large numbers.
The cave bear inhabited low mountainous areas, especially in regions rich in 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....
caves. They seem to have avoided open plains, preferring forested or forest-edged terrains.
Anatomy
The cave bear had a very broad, domed skull with a steep forehead. Its stout body had long thighs, massive shins and in-turning feet, making it similar in skeletal structure to the brown bear. Cave bears were comparable in size to the largest modern day bears. The average weight for males was 400–500 kilograms (880–1102 pounds), while females weighed 225–250 kg (496–551 lbs). Of cave bear skeletons in museums, 90% are male due to a misconception that the female skeletons were merely "dwarfs". Cave bears grew larger during glaciations and smaller during interglacials, probably to adjust heat loss rate. Cave bears of the last ice ageIce age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...
lacked the usual 2–3 premolars present in other bears; to compensate, the last molar is very elongated, with supplementary cusps. The humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
of the cave bear was similar in size to that of the polar bear
Polar Bear
The polar bear is a bear native largely within the Arctic Circle encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the world's largest land carnivore and also the largest bear, together with the omnivorous Kodiak Bear, which is approximately the same size...
, as were the femora of females. The femora of male cave bears, however, bore more similarities in size to those of kodiak bear
Kodiak Bear
The Kodiak bear , also known as the Kodiak brown bear or the Alaskan grizzly bear or American brown bear, occupies the islands of the Kodiak Archipelago in South-Western Alaska. Its name in the Alutiiq language is Taquka-aq. It is the largest subspecies of brown bear.- Taxonomy :Taxonomist C.H...
s.
Dietary habits
Cave bear teeth show greater wear than most modern bear species, suggesting a diet of tough materials. However, tubers and other gritty food, which cause distinctive tooth wear in modern brown bears, do not appear to have constituted a major part of cave bears' diet on the basis of dental microwear analysis.The morphological features of the cave bear chewing apparatus, including loss of premolars, have long been suggested to indicate that their diets displayed a higher degree of herbivory than the Eurasian brown bear
Eurasian Brown Bear
The Eurasian brown bear is a subspecies of brown bear, found across northern Eurasia. The Eurasian brown bear is also known as the common brown bear, European brown bear and colloquially by many other names....
. Indeed, a solely vegetarian diet has been inferred on the basis of tooth morphology. Results obtained on the stable isotopes of cave bear bones also point to a largely vegetarian diet in having low levels of nitrogen-15 and carbon-13
Carbon-13
Carbon-13 is a natural, stable isotope of carbon and one of the environmental isotopes. It makes up about 1.1% of all natural carbon on Earth.- Detection by mass spectrometry :...
, which are accumulated at a faster rate by meat eaters as opposed to herbivores.
However, some evidence points toward inclusion of at least occasional animal protein in the cave bear diet. For example, toothmarks on cave bear remains in areas where cave bears are the only recorded potential carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
s suggests occasional cannibalistic scavenging, possibly on individuals that died during hibernation, and dental microwear analysis indicates that the cave bear may have fed on a greater quantity of bone than its contemporary, the smaller Eurasian brown bear. Additionally, cave bear remains from Peştera cu Oase
Pestera cu Oase
Peștera cu Oase is a system of 12 karstic galleries and chambers located N. 45° 01’; E. 21° 50’ in southwestern Romania, where the oldest early modern human remains in Europe have been discovered.-Paleoanthropological on-site findings:...
in the southwestern tip of the Carpathian mountains
Carpathian Mountains
The Carpathian Mountains or Carpathians are a range of mountains forming an arc roughly long across Central and Eastern Europe, making them the second-longest mountain range in Europe...
had elevated levels of nitrogen-15 in their bones, indicative of an omnivorous
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...
diet, although the values are within the range of those found for the strictly herbivorous mammoth
Mammoth
A mammoth is any species of the extinct genus Mammuthus. These proboscideans are members of Elephantidae, the family of elephants and mammoths, and close relatives of modern elephants. They were often equipped with long curved tusks and, in northern species, a covering of long hair...
.
Although the current prevailing opinion concludes that cave bears were largely herbivorous, and more so than any modern species of the genus Ursus
Ursus (genus)
Ursus is a genus in the family Ursidae that includes the widely distributed brown bears, the polar bear, and black bears. The name is derived from the Latin ursus, meaning bear.-Species and subspecies of Ursus:...
, increasing evidence points to an omnivorous diet, based both on regional variability of isotopic composition of bone remains indicative of dietary plasticity, and on a recent reevaluation of its craniodental morphology that places the cave bear squarely among omnivorous modern bear species with respect to its skull and tooth shapes.
Mortality
Dental caries
Dental caries, also known as tooth decay or a cavity, is an irreversible infection usually bacterial in origin that causes demineralization of the hard tissues and destruction of the organic matter of the tooth, usually by production of acid by hydrolysis of the food debris accumulated on the...
, tooth resorption
Root resorption
In dentistry, root resorption is the breakdown or destruction, and subsequent loss, of the root structure of a tooth. This is caused by living body cells attacking part of the tooth. When the damage extends to the whole tooth, it is called tooth resorption...
, necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
(particularly in younger specimens), osteomyelitis
Osteomyelitis
Osteomyelitis simply means an infection of the bone or bone marrow...
, periostitis
Periostitis
Periostitis, also known as periostalgia, is a medical condition caused by inflammation of the periosteum, a layer of connective tissue that surrounds bone...
, rickets
Rickets
Rickets is a softening of bones in children due to deficiency or impaired metabolism of vitamin D, magnesium , phosphorus or calcium, potentially leading to fractures and deformity. Rickets is among the most frequent childhood diseases in many developing countries...
and kidney stones. Male cave bear skeletons have been found with broken baculum
Baculum
The baculum is a bone found in the penis of most mammals. It is absent in humans, but present in other primates, such as the gorilla and chimpanzee.The bone aids in sexual intercourse.-Purpose:...
s, probably due to fighting during breeding season. Cave bear longevity
Longevity
The word "longevity" is sometimes used as a synonym for "life expectancy" in demography or known as "long life", especially when it concerns someone or something lasting longer than expected ....
is unknown, though it has been estimated that they seldom exceeded 20 years of age. Paleontologists doubt adult cave bears had any natural predators, save for pack hunting wolves and cave hyena
Cave Hyena
The Cave Hyena is an extinct subspecies of spotted hyena native to Eurasia, ranging from Northern China to Spain and into the British Isles...
s which would probably have attacked sick or infirm specimens. Cave hyenas are thought to be responsible for the dis-articulation and destruction of some cave bear skeletons. Such large carcasses were an optimal food resource for the hyenas, especially at the end of the winter, when food was scarce. The presence of fully articulated adult cave lion
Cave lion
Panthera leo spelaea also known as the European or Eurasian cave lion, is an extinct subspecies of lion known from fossils and many examples of prehistoric art.-Physical characteristics:This subspecies was one of the largest lions...
skeletons, deep in cave bear dens, indicates that lions may have occasionally entered dens to prey on hibernating cave bears, with some dying in the attempt.
Evolution
Both the cave bear and the brown bear are thought to be descended from the PlioPliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
-Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
Etruscan bear (Ursus etruscus
Ursus etruscus
Ursus etruscus is an extinct species of mammal of the family Ursidae , endemic to Europe, Asia and North Africa during the Pliocene through Pleistocene, living from ~5.3 Mya—11,000 years ago, existing for approximately ....
) that lived ~5.3 Mya to 10,000 years ago. The last common ancestor of cave bears and brown bears lived between 1.2 and 1.4 million years ago. The immediate precursor of the cave bear was probably Ursus deningeri
Ursus deningeri
Ursus deningeri is an extinct species of mammal of the family Ursidae , endemic to Europe during the Pleistocene, living from ~1.8 Mya—100,000 years ago, existing for approximately ....
(Deninger's bear), a species restricted to Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
Europe ~1.8 Mya to 100,000 years ago. The transition between Deninger's bear and the cave bear is given as the last Interglacial, although the boundary between these forms is arbitrary and intermediate or transitional taxa have been proposed, e.g. Ursus spelaeus deningeroides, while other authorities consider both taxa to be chronological variants of the same species.
Cave bears found in different regions vary in age, thus facilitating investigations into evolutionary trends. The three anterior premolar
Premolar
The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...
s were gradually reduced, then disappeared, possibly in response to a largely vegetarian diet. In a fourth of the skulls found in the Conturines, the third premolar is still present, while more derived
Derived
In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...
specimens elsewhere lack it. The last remaining premolar became conjugated with the true molars
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
, enlarging the crown and granting it more cusps and cutting borders. This phenomenon known as molarization improved the mastication
Mastication
Mastication or chewing is the process by which food is crushed and ground by teeth. It is the first step of digestion and it increases the surface area of foods to allow more efficient break down by enzymes. During the mastication process, the food is positioned between the teeth for grinding by...
capacities of the molars, facilitating the processing of tough vegetation. This allowed the cave bear to gain more energy for hibernation while eating less than its ancestors.
Recovery of fossil DNA
In May 2005, scientists in CaliforniaCalifornia
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
succeeded in recovering and sequencing
DNA sequencing
DNA sequencing includes several methods and technologies that are used for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA....
nuclear DNA
Nuclear DNA
Nuclear DNA, nuclear deoxyribonucleic acid , is DNA contained within a nucleus of eukaryotic organisms. In mammals and vertebrates, nuclear DNA encodes more of the genome than the mitochondrial DNA and is composed of information inherited from two parents, one male, and one female, rather than...
of a cave bear that lived between 42,000 and 44,000 years ago. The procedure used genomic DNA extracted from the animal's tooth
Tooth
Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...
. Sequencing the DNA directly (rather than first replicating it with the polymerase chain reaction
Polymerase chain reaction
The polymerase chain reaction is a scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence....
), the scientists were able to recover 21 cave bear gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
s from remains that did not yield significant amounts of DNA with traditional techniques. This study confirmed and built on results from a previous study using mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
extracted from cave bear remains ranging from 20,000 to 130,000 years old. Both show the cave bear to be more closely related to the brown bear
Brown Bear
The brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...
and polar bear
Polar Bear
The polar bear is a bear native largely within the Arctic Circle encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the world's largest land carnivore and also the largest bear, together with the omnivorous Kodiak Bear, which is approximately the same size...
than the American black bear
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...
, but having split from the brown bear lineage prior to the diversification of distinct eastern and western brown bear lineages and prior to the split of brown bears and polar bears. The divergence
Genetic divergence
Genetic divergence is the process in which two or more populations of an ancestral species accumulate independent genetic changes through time, often after the populations have become reproductively isolated for some period of time...
date estimate of cave bears and brown bears is ~1.2–1.4 Mya.
Causes of extinction
Recent reassessment of fossils indicate the cave bear probably died out 27,800 years ago. It has been suggested that a complex set of factors, rather than a single factor, led to the extinction.Compared with other megafauna
Megafauna
In terrestrial zoology, megafauna are "giant", "very large" or "large" animals. The most common thresholds used are or...
l species that also became extinct during the last Glacial Maximum, the cave bear was believed to have had a more specialized diet of high-quality plants and a relatively restricted geographical range. This was suggested as an explanation as to why it died out so much earlier than the rest. Some experts have disputed this claim as the cave bear had survived multiple climate changes prior to extinction. Additionally, mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
research indicated that the genetic decline of the cave bear began long before it went extinct, demonstrating that habitat loss due to climate change was not responsible. Finally, high δ15N levels were found in cave bear bones from Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
, indicating wider dietary possibilities than previously believed.
Overhunting by human
Human
Humans are the only living species in the Homo genus...
s has been largely dismissed because human populations at the time were too small to pose a serious threat to the cave bear's survival, though there is evidence that the two species may have competed for living space in caves. Unlike brown bears, cave bears are seldom represented in cave paintings, leading some experts to believe that the cave bear may have been avoided by human hunters or their habitat preferences may not have overlapped. The late paleontologist Bjorn Kurten
Björn Kurtén
Björn Olof Lennartson Kurtén was a distinguished vertebrate paleontologist. He belonged to the Swedish-speaking minority in Finland. He was a professor in paleontology at the University of Helsinki from 1972 up to his death in 1988...
hypothesized
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
that cave bear populations were fragmented and under stress even before the advent of the glaciers. It is possible that populations living south of the Alps
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
survived significantly longer.
There is some evidence that the cave bear only used caves for hibernation and was not inclined to use other locations, such as thicket
Thicket
A thicket is a very dense stand of trees or tall shrubs, often dominated by only one or a few species, to the exclusion of all others. They may be formed by species that shed large amounts of highly viable seeds that are able to germinate in the shelter of the maternal plants.In some conditions the...
s, for this purpose, in contrast to the more versatile brown bear
Brown Bear
The brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...
. This specialized hibernation behavior would have caused a high winter mortality rate for cave bears that failed to find available caves. Therefore, as human populations slowly increased, the cave bear faced a shrinking pool of suitable caves, and slowly faded away to extinction, as both Neanderthals and anatomically modern humans sought out caves as living quarters, depriving the cave bear of vital habitat. This hypothesis is being researched at this time.
Cave bear worship
Collections of bear bones at several widely dispersed sites suggest that NeanderthalNeanderthal
The Neanderthal is an extinct member of the Homo genus known from Pleistocene specimens found in Europe and parts of western and central Asia...
s may have worship
Worship
Worship is an act of religious devotion usually directed towards a deity. The word is derived from the Old English worthscipe, meaning worthiness or worth-ship — to give, at its simplest, worth to something, for example, Christian worship.Evelyn Underhill defines worship thus: "The absolute...
ped cave bears, especially at Drachenloch, in Switzerland, where a stone chest was discovered with a number of bear skulls stacked upon it. Neanderthals, who also inhabited the entrance of the cave, are believed to have built it. A massive stone slab covered the top of the structure. At the cave entrance, seven bear skulls were arranged with their muzzles facing the cave entrance, while deeper in the cave, a further six bear skulls were lodged in niches along the wall. Next to these remains were bundles of limb bones belonging to different bears. Consequently, it was at this site that the supposed symbol of the "Cult of the Cave Bear" was found. This consisted of the skull of a three-year-old bear pierced in the cheek by the leg-bone of younger bear. The arrangement of these bones of different bears are not believed to have happened by chance.
A similar phenomenon was encountered in Regourdou, southern France. A rectangular pit contained the remains of at least twenty bears, covered by a massive stone slab. The remains of a Neanderthal lay nearby in another stone pit, with various objects, including a bear humerus, a scraper, a core, and some flakes, which were interpreted as grave offerings.
The unusual finding in a deep chamber of Basua Cave in Savona
Savona
Savona is a seaport and comune in the northern Italian region of Liguria, capital of the Province of Savona, in the Riviera di Ponente on the Mediterranean Sea....
, Italy, is thought to be related to cave bear worship, as there is a vaguely zoomorphic stalagmite
Stalagmite
A stalagmite is a type of speleothem that rises from the floor of a limestone cave due to the dripping of mineralized solutions and the deposition of calcium carbonate. This stalagmite formation occurs only under certain pH conditions within the underground cavern. The corresponding formation on...
surrounded by clay pellets. It was apparently used by Neanderthals for a ceremony; the fact that bear bones lay scattered on the floor further suggests that this was likely to have had some sort of ritual purpose.