Sperm whale (Physeter catodon)
Sperm whales swim through deep waters to depths of 2 miles,
apparently limited in depth only by the time it takes to swim
down and back to the surface. Their distributions are depend
upon season and sexual/social status, however they are most
likely to be found in waters inhabited by squid- at least 1,000
m deep and with cold-water upswellings. Because they are so
well-adapted for deep water swimming, they are in real danger
of stranding when they move inshore.
Above weights are given for mature male giant sperm whales.
Females only weigh about 1/3 as much as males. Males may reach
19 m while females are only 12 meters. Newborn calves measure
about 4 m and are about 1/25 the weight of females.
The enormous (up to 1/3 of total body length), box-like head
of Physeter catodon sets it apart from all other species. The
head contains a spermaceti organ whose function is not entirely
known. It may serve to focus and reflect sound or may be a cooling
organ to diminish the whale's volume and its buoyancy during
prolonged dives. The giant sperm whale has the largest of mammalian
brains in terms of sheer mass (approximately 9 kg). The blowhole
slit is S-shaped and positioned on the left side of the head.
There are 18-28 functional teeth on each side of the lower jaws,
but the upper teeth are few, weak and nonfunctional. The lower
teeth fit into sockets in the upper jaw. The gullet of Physeter
catodon is the largest among cetaceans; it is in fact the only
gullet large enough to swallow a human.
The dorsal fin is replaced by a hump and by a series of longitudinal
ridges on the posterior part of the back, and the pectoral fins
are quite small, approximately 200 cm. long. Tail flukes are
400-450 cm. The blubber layer of the giant sperm whale is quite
thick, up to 35 cm. With respect to coloration, males often
become paler and sometimes piebald with age. Both sexes have
white in the genital and anal regions and on the lower jaws.
Giant sperm whales are very deep divers and may stay submerged
from 20 minutes to over an hour. When they surface, sperm whales
typically blow 20-70 times before redescending. They produce
a visible spout made by the condensation of the moisture combined
with a mucous foam from the sinuses. Giant sperm whales typically
swim at speeds no faster than 10 km per hour, but when disturbed
they can attain speeds of 30 km per hour.
Giant sperm whales are highly gregarious and group themselves
roughly by age and sex in group sizes of 100 or more individuals.
Loose family groups of about 30 individuals, however, are more
common. Groups are often made up of either bachelor bulls (sexually
inactive males) or "nursery schools" of mature females
and juveniles of both sexes. Older males are usually solitary
except during the breeding season.
Sperm whales use clicking noises for echolocation, but they
also make a variety of other sounds including "groans,
whistles, chirps, pings, squeaks, yelps, and wheezes" (Ellis
1980). Their voices are quite loud and can be heard many kilometers
away with underwater listening devices. Each whale also emits
a stereotyped, repetitive sequence of 3-40 or more clicks when
it meets another whale. This sequence is known as the whale's