Pygmy Sperm Whale
Encyclopedia
The Pygmy Sperm Whale is one of three species
of toothed whale
in the sperm whale family
. They are not often sighted at sea, and most of what is known about them comes from the examination of stranded specimens.
s (see sperm whale family
for details). The two were widely considered to be the same species, until 1966, when a scientist at the Smithsonian Institution
definitively identified them as separate species. The pygmy sperm whale was first named by de Blainville
in 1838.
, the pygmy sperm whale has a spermaceti
organ in its forehead (see Sperm Whale
for a discussion of its purpose). It also has a sac in its intestines that contains a dark red fluid. The whale will expel this fluid when frightened. Its purpose is believed to be to confuse and disorient predators.
The Pygmy Sperm is not much larger than many dolphin
s. They are about 1.2 m (3.7 feet) at birth, growing to about 3.5 m (10.4 feet) at maturity. Adults weigh about 400 kg. The underside is a creamy, occasionally pinkish, colour and the back and sides are a bluish grey; there is, however, considerable intermixing between the two colours. The shark-like head is large in comparison to body size, given an almost swollen appearance when viewed from the side. The lower jaw is very small and slung low. The blowhole is displaced slightly to the left when viewed from above facing forward. The dorsal fin
is very small and hooked; its size is considerably smaller than the Dwarf Sperm Whale's and may be used for diagnostic purposes. The Pygmy Sperm has between 20 and 32 teeth, all of which are set into the lower jaw. Unusually, this species teeth lack enamel due to a mutation in the necessary gene. There is a false gill behind each eye.
This whale makes very inconspicuous movements. It rises to the surface slowly, with little splash or blow, and will remain there motionless for some time. In Japan
the whale was historically known as the "floating whale" because of this. Its dive is equally lacking in grand flourish - it simply drops out of view. The species has a tendency to back away from rather than approach boats. Breaching has been observed, but is not common.
Pygmy Sperms are usually solitary creatures but have been seen in groups of up to six. Primary food sources are squid
and crab
s.
s. However, they are rarely sighted at sea, so most data comes from stranded animals - making a precise range and migration map difficult. They are believed to prefer off-shore waters. Their status is usually described as rare, but occasional patches of higher density of strandings suggest it may be rather more common than previously supposed. The total population is unknown.
, Japan
and the Lesser Antilles
. Individuals have also been recorded killed in drift nets. Some stranded animals have been found with plastic bags in their stomachs - which may be a cause for concern. It is not known whether these activities are causing long-term damage to the survival of the species.
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 toothed whale
Toothed whale
The toothed whales form a suborder of the cetaceans, including sperm whales, beaked whales, dolphins, and others. As the name suggests, the suborder is characterized by the presence of teeth rather than the baleen of other whales.-Anatomy:Toothed whales have a single blowhole on the top of the head...
in the sperm whale family
Sperm whale family
Physeteroidea is a superfamily including just three living species of whale; the Sperm Whale, in the genus Physeter, and the Pygmy Sperm Whale and Dwarf Sperm Whale, in the genus Kogia...
. They are not often sighted at sea, and most of what is known about them comes from the examination of stranded specimens.
Taxonomy
There has been debate and differing opinion as to the correct classification of the Pygmy and Dwarf Sperm WhaleDwarf Sperm Whale
The Dwarf Sperm Whale is one of three species in the sperm whale family. They are not often sighted at sea. As such, most information is a result of the study of stranded carcasses.-Taxonomy:...
s (see sperm whale family
Sperm whale family
Physeteroidea is a superfamily including just three living species of whale; the Sperm Whale, in the genus Physeter, and the Pygmy Sperm Whale and Dwarf Sperm Whale, in the genus Kogia...
for details). The two were widely considered to be the same species, until 1966, when a scientist at the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
definitively identified them as separate species. The pygmy sperm whale was first named by de Blainville
Henri Marie Ducrotay de Blainville
Henri Marie Ducrotay de Blainville was a French zoologist and anatomist.Blainville was born at Arques, near Dieppe. In about 1796 he went to Paris to study painting, but he ultimately devoted himself to natural history, and attracted the attention of Georges Cuvier, for whom he occasionally...
in 1838.
Physical description
Like its giant cousin, the Sperm WhaleSperm Whale
The sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...
, the pygmy sperm whale has a spermaceti
Spermaceti
Spermaceti is a wax present in the head cavities of the sperm whale . Originally mistaken for the whales' sperm , spermaceti is created in the spermaceti organ inside the whale's head and connected to its nasal passage...
organ in its forehead (see Sperm Whale
Sperm Whale
The sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...
for a discussion of its purpose). It also has a sac in its intestines that contains a dark red fluid. The whale will expel this fluid when frightened. Its purpose is believed to be to confuse and disorient predators.
The Pygmy Sperm is not much larger than many dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
s. They are about 1.2 m (3.7 feet) at birth, growing to about 3.5 m (10.4 feet) at maturity. Adults weigh about 400 kg. The underside is a creamy, occasionally pinkish, colour and the back and sides are a bluish grey; there is, however, considerable intermixing between the two colours. The shark-like head is large in comparison to body size, given an almost swollen appearance when viewed from the side. The lower jaw is very small and slung low. The blowhole is displaced slightly to the left when viewed from above facing forward. The dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
is very small and hooked; its size is considerably smaller than the Dwarf Sperm Whale's and may be used for diagnostic purposes. The Pygmy Sperm has between 20 and 32 teeth, all of which are set into the lower jaw. Unusually, this species teeth lack enamel due to a mutation in the necessary gene. There is a false gill behind each eye.
This whale makes very inconspicuous movements. It rises to the surface slowly, with little splash or blow, and will remain there motionless for some time. In Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
the whale was historically known as the "floating whale" because of this. Its dive is equally lacking in grand flourish - it simply drops out of view. The species has a tendency to back away from rather than approach boats. Breaching has been observed, but is not common.
Pygmy Sperms are usually solitary creatures but have been seen in groups of up to six. Primary food sources are squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
and crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s.
Population and distribution
Pygmy sperm whales are found in the temperate waters of the Atlantic, Pacific and Indian OceanIndian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
s. However, they are rarely sighted at sea, so most data comes from stranded animals - making a precise range and migration map difficult. They are believed to prefer off-shore waters. Their status is usually described as rare, but occasional patches of higher density of strandings suggest it may be rather more common than previously supposed. The total population is unknown.
Human interaction
Pygmy sperm whales have never been hunted on a wide scale. Land-based whalers have hunted them from IndonesiaIndonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
and the Lesser Antilles
Lesser Antilles
The Lesser Antilles are a long, partly volcanic island arc in the Western Hemisphere. Most of its islands form the eastern boundary of the Caribbean Sea with the Atlantic Ocean, with the remainder located in the southern Caribbean just north of South America...
. Individuals have also been recorded killed in drift nets. Some stranded animals have been found with plastic bags in their stomachs - which may be a cause for concern. It is not known whether these activities are causing long-term damage to the survival of the species.
Specimens
- MNZ MM002651, collected Hawke's Bay, New Zealand, no date data.