Order C ETAC EA
WHALES, DOLPHINS, and PORPOISES
T h e C e t a c e a n s , the Whales, Dolphins and their allies, are for the most part
huge animals dwelling in the sea, which suckle their young like the terrestrial
mammals. They present structural peculiarities specially suited for an aquatic
existence. In general form they resemble certain fishes, and the head and limbs
are so designed that progression through their natural element is easy.
The head is, relatively speaking, very large, and the single or double nostril
or blowhole is placed far back near the crown. The eyes are small, so also are
the ears, which have very small external apertures. Water is so excellent a
conductor of sound that the internal hearing apparatus is sufficient for all purposes.
The body is long and fishlike, the head joining the vertebrae of the backbone
without any indication of a neck except in the case of the Balamofitera. The
front limbs are formed into large paddles without toes or segments, and the hind
limbs are externally absent, although rudimentary in all species.1 The tail is
placed horizontally"; it is broad and notched in the centre of its hinder edge.
Most of the Cetaceans have a large vertical fin in the middle of the back,
analogous to the fins of sharks and other fish. This is most noticeable when
the animal rolls over on the surface after spouting. Save in immatures and a
few adults of certain species there are no hairs or bristles; the skin is very
smooth and polished, and beneath this, when the animal is in good health,
there is an abundance of fat or blubber.
Some of the Cetaceans frequent the deep seas, while others seem to prefer
the vicinity of the coasts. Others, again, frequent estuaries and even ascend
rivers, on whose banks they are occasionally stranded. They are carnivorous
in their diet, feeding, in the case of the Great Fin Whales, on such small animals
as shrimps, and in the case of the Sperm Whale on such immense creatures as
the giant decapods. Most of the small species live on fish, while the fierce
Killer will prey on seals and any wounded or disabled member of its own order,
and will even attack the largest species. Whales are capable of suspending the
1 These vestiges are simply fragments of the thighbones and sometimes of the tibia.