Dwarf sperm whale (Kogia simus)
This robust cetacean is the smallest of all whales, and closely
resembles the Pygmy Sperm Whale in size, stature and colour.
However, the snout of the Dwarf Sperm Whale becomes blunt and
square, not rectangular, in adulthood, and the dorsal fin is
larger. There are a number of small irregular grooves on the
throat behind the mouth. There are between fourteen and twenty-four
teeth on the lower jaw, with up to three pairs on the upper.
They are dark bluish grey in colour, lightening to a pinkish
off-white underneath. Maximum weight is around 210kg, with a
maximum length of 2.7m being attained in both sexes.
The Dwarf Sperm Whale can be easily confused with the Pygmy
Sperm Whale, and other blunt-headed cetaceans (such as Risso's
Dolphin, the Pygmy Killer Whale and the Melon-Headed Whale).
However, the Dwarf Sperm Whale has a more square-shaped head
and moves much slower than the other species of blunt-headed
cetacean, and it has a larger dorsal fin than the Pygmy Sperm
Whale.
Dwarf Sperm Whales are oceanic animals, moving across and over
the continental shelf to feed.
Like the Pygmy Sperm Whale, this species of cetacean is slow-moving
and hunts by stealth, so prey are probably incapable of fast
movement - therefore, again like the Pygmy Sperm Whale, the
Dwarf Sperm Whale eats small fish, cuttlefish, deepsea shrimps
and squid.
Pods contain less than ten animals, mainly females with calves
and sexually immature males. The behaviour of the Dwarf Sperm
Whale is very similar to that of the Pygmy Sperm Whale. The
blow is inconspicuous and low, and after blowing the cetacean
simply drops out of sight. It rarely approaches boats, and when
startled evacuates a reddish-brown intestinal fluid as a decoy
before it dives.