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Whales - meet the different species
All modern mysticetes, comprising 4 families, are large whales with baleen instead of teeth. Baleen consists of long plates inside the mouth made of keratin which filters their prey. Keratin is the same substance found in human fingernails and hair. The exact means by which baleen is used differs among species (gulp-feeding with balaenopterids, skim-feeding with balaenids, and bottom-feeding with eschrichtiids). All of these whales have a double blowhole, a symmetrical skull and only one sternum bone. They can be found in all the world's oceans and can undertake some of the longest migrations known to man.
Four species of right and bowhead whales make up this family. These are the ‘tanks’ of the whale kingdom. Individuals can grow up to 20m and weigh as much as 90,000kg. With a robust and rotund body, no dorsal fin or ridge, and with a head that measures at least a third of its total body length, members of this whale family can look intimidating! They are, however, slow animals feeding passively by skim-feeding, aided by the longest baleen with the finest baleen sieves of all mysticetes. All species were once intensively whaled and, to date, have been slow to recover. Although two of the four species are listed as ‘Least Concern’, almost all the populations of all species in this family are listed as ‘Endangered’ or higher on the IUCN Red list. Subsistence whaling of bowhead whales is still practiced by Alaskan and Greenlandic aboriginal subsistence whalers.
Balaena mysticetus (Bowhead whale)
Otherwise known as the ‘rorquals’, there are 8 species in this family, although the Bryde’s whale may soon be split into more than 1 species. If balaenids are the ‘tanks’, then balaenopterids are the ‘sports cars’ of the whale kingdom; sleek, slender and incredibly hydrodynamic, these whales slip effortlessly through the water despite their immense size. All members of the family reach lengths of over 7m with a dorsal fin of varying shape and size. They are lunge-feeders and have long pleats extending from the snout to the navel enabling massive distention of the throat when they take in huge quantities of water before sifting out their food. The balaenopterids (or rorquals) can be distinguished from one another by the varying length, width and number of baleen plates, as well as overall size and pigmentation.
There is only one species in this family, the gray whale. A stocky animal with a slightly arched jaw, they are another relatively slow-moving species, preferring shallow and coastal waters. Gray whales have the shortest (and coarsest) baleen of all mysticetes, possibly due to their preference for bottom-ploughing for food. Only two populations of this species remain, an Atlantic population having been wiped out, perhaps partly due to early whaling (although the cause remain a mystery), by 1675 or possibly the early 18th century. The remaining populations are the ‘western North Pacific’ (or Asian) and ‘eastern North Pacific’. Both populations undergo annual migrations; the eastern population travels from the cold, food-rich North Pacific waters to the warmer breeding grounds of the lagoons of Baja California, Mexico, but little is known of the Asian populations’ route and winter breeding grounds.
This is another family with only one species; the pygmy right whale. As the name suggests, this is a relatively small whale, reaching 6.5m in length and a weight of 3,400kg. There is very little known of this species, with only a few living animals having been found on southern hemisphere shores.
The remaining "whales" are toothed whales belonging to the ...
This family contains two species, the dwarf and pygmy sperm whales. Both occur off shore in deep water habitats and both are poorly known. They are far smaller than the sperm whale to which they only bear a slight resemblance.
This family is known as the white whale group. It contains two species: the beluga and narwhal. Both are small and stocky with bulbous and blunt heads, rounded flippers and flukes and no dorsal fin. The single tooth of the narwhal, the so called tusk, is the longest of the odontocetes. Normally a male characteristic, the tusk is sometimes seen in females and sometimes there are two tusks erupting, with the second one typically shorter than the first. The cervical vertebrae of both species are not fused, allowing for a greater range of neck flexibility. Both species are restricted to the cold waters of the Arctic.
This is a single species family containing the sperm whale or cachalot, the largest of the toothed whales and also the one that exhibits the highest degree of sexual dimorphism (the male grows up to 18 m long and has a huge head accounting for 2/5 of his body length; the female only grows to 12 m long. The teeth are only present on the narrow, underslung lower jaw and instead of a fin they have a low dorsal hump.
This family comprises 21 species of beaked whales. All are medium to large-sized animals, with the females typically larger than the males. With 3 exceptions (the two Berardius species and Tasmacetus) it is only the males that have 1 or 2 pairs of functional teeth on their lower jaw. The Ziphiidae contains the ocean’s most mysterious whales; in some cases only remnants of skulls or partial skeletons exist as evidence of living species at sea. It is expected that future revisions of this family will occur as each and every sighting of these species increases our knowledge.