Cephalorhynchus Commersonii
While they may look like porpoises with their stocky body
shape and their small, indistinct rostrum, the Commerson's
dolphin is unmistakably part of the dolphin family with its
bold, outgoing behavior. Because of its striking black and
white patterns, this dolphin is also called by other names
such as the Skunk dolphin and the Piebald dolphin. Typical
coloration of an adult would be a black colored head, with
a large black area sweeping back from the dorsal fin to the
flukes. It has a white patch on its throat that travels beneath
its pectoral fins, then sweeps upwards, covering the whole
midsection of the dolphin in white, with a small black patch
on the underside that may come up slightly to the sides of
the dolphin. At birth, these dolphins don't have the flashy
black and white pattern, but are grey, black, and brown. As
it grows older, it will become black and grey, with the grey
patches developing into the white coloration that the adults
possess.
Unlike most dolphins, the dorsal fin of the Commerson's dolphin
is wide and rounded. It may curve back slightly, though some
individuals have a less rounded find that is almost triangular
in shape. Their pectoral fins are rounded as well, and are
a solid black on both the top and the undersides.
Commerson's dolphins can be found in shallow waters along
the southernmost tip of South America and in the Kerguelen
Islands in the Indian Ocean. They can often be found in naturally
protected waters or harbors, sometimes entering the mouths
of rivers. These dolphins are most commonly found in the Straits
of Magellan, the Falkland Islands, and around Tierra del Fuego,
often around kelp beds. They have anywhere from 108-138 teeth,
and feed on just about anything, such as fish, squid or octopus,
crustaceans such as shrimp, and some other invertebrates as
well, most likely foraging near the sea floor for their meals.
Being dolphins, they are quite active and can swim very quickly,
usually around the surface of the water. Commerson's are active
breachers, and may breach repeatedly in a short period of
time. They may even surf, riding breakers close to shore or
heavy swells out at sea. Bowriding is a common behavior, and
they may also swim behind vessels, playing in the wake. Underwater,
a Commerson's dolphin may engage in swimming upsidedown or
spinning while swimming.
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