The sperm whale has the largest brain of any living species today, as well as being the largest toothed whale species
It is one of the deepest diving mammals, coming second to Cuvier’s beaked whale. The head, which also houses the spermaceti organ, occupies about one third of the sperm whale’s body. The name sperm whale derive from the oil contained in the spermaceti organ, which early whalers thought was semen. In fact the spermaceti organ is used by whales to communicate, which is an important feature of this very sociable animal’s life. The spermaceti organ may also help the sperm whale with diving, with controlled blood vessels and cold water causing the wax in the oil to solidify, increasing the whale’s specific density, providing a downforce that allows the animal to dive with less effort. The same may be true for surfacing; with oxygen consumption and an increase in metabolism and blood flow generating heat that melts to solidified waxes in the spermaceti making it easier to ascend. They feed mainly on squid and fish, to catch this prey, sperm whales are able to dive up to 2km deep for 45 minutes at a time. It was estimated in 2003 that there were approximately 360,000 sperm whales. This is a 68% decrease in population size compared to the pre-hunting estimate of 1,100,000. Sperm whales were hunted between the early 17th and mid 19th century for their oil. Today, Japan is the only country which still continues to hunt this species. It is the sole living species in its genus, Physeter, and is one of three species within the family, Physeteridae. It is more closely related to dolphins and porpoise than to large baleen whales like the blue whale.
- Order: Cetartiodactyla
- Family: Physeteridae
- Population: 360,000
- Trend: unknown
- Size: 11-18m
- Weight: 15-45t
Sperm whales’ are found globally across all oceans, between the latitudes of 40° in the south and 50° in the north.
Habitat and Ecology
These marine mammals are found in oceans across the globe. Females show a greater preference for warmer water than males, and tend to stay in latitudes where the sea temperature is 15°C or more. They are rarely found in shallow water less than 1km deep. Sperm whales are extremely sociable mammals with females and juveniles traveling together in large groups of about twenty or thirty whales. Individuals communicate vocally with each other, and there is a lot of physical contact. They eat a varied diet, with males eating up to 1,000kg of medium sized fish and squid each day. They are also known to eat crabs, jellyfish and sponges, and rubbish they mistake for prey. They have a low reproductive rate, with a female producing one calf every 4-6 years.