By Amelia Meyer
Scientific Name: Physeter macrocephalus
Other Names: Cachalot, Great Sperm Whale
The Sperm Whale has a particularly wide distribution and is one of the better known whales to the average person. It is characterised by its huge, blunt snout and square head. This head comprises about a third of the entire body. Although the Sperm Whale is still relatively abundant, it continues to be one of the worst exploited animals on the planet.
Sperm Whale under water.
The stocky body of the Sperm Whale is grey with a light grey or white underside. These white markings extend up its lower jaw and onto the front of the broad, flat snout. There is a thick keel that supports the broad tail fin. This fin has straight trailing edges that are usually frayed or jagged with a deep central notch. The Sperm Whale does not have a dorsal fin, but rather has a rounded hump with similar (but smaller) knuckles behind it, giving its back a knobbled effect. The pectoral flippers are short and stumpy.
The lower jaw is so small that, when the mouth is closed, it is barely visible. Adult Sperm Whales reach a length of between 11 and 18 metres (or between 36 and 59 feet) and weigh anything between 20 and 50 tonnes.
Although they usually only dive for about 40 to 50 minutes at a time, it is possible for the Sperm Whale to remain submerged for up to two hours. They usually surface around the same area and stay almost motionless. Occasionally, they will swim slowly. They can reach high swimming speeds when they are threatened.
In terms of travelling together, the vast majority of Sperm Whales will either be a part of a bachelor school (comprising of young pre-sexual males) or a breeding schools (females that travel with young of both genders). Both of these schools are generally made up of about 20 individuals. Older males will, for the most part, travel alone. Hundreds of individuals have been known to travel together on rare occasions.
Where to Find Them
The Sperm Whale sticks to deep waters all over the world, both inshore and offshore. Still, their distribution is more abundant in certain areas than in others. They are most commonly found in submarine canyons on the edges of continental shelves. In summer, they move towards the northern and southern poles, while winter is usually spent in the warmer tropical and temperate waters of the world’s oceans.
Although it has no top teeth, the Sperm Whale has between 36 and 50 teeth in the lower jaw. They use these to eat squid and fish. Of course, the specific type of fish varies according to the habitat of different individuals and communities.
The Sperm Whale has been one of the biggest victims to human hunting and interference to date. Still, their population numbers are high. Their major threats include fishing nets (in which they become tangled and drown), pollution and human disturbance.