Physeter macrocephalus, Linnaeus, 1758

Sperm whales live either in reproductive pods or in bachelor pods. In a reproductive pod live females of all ages and a number of young males. When a young male becomes mature it leaves the pod and joins a bachelor pod. The bachelor pods consist of a few males of 7 to 27 years of age. Older males live often singly. During the breeding season they visit the reproductive pods to mate. These whales make deep dives to depths of up to 3,000 meters that can last as long as two hours. No other mammal dives deeper.

Right in front of us you see two skulls of whales and a complete skeleton of een baleen whale. The right skull is of a baleen whale, the left one of a sperm whale. At the rear, you see a large crest on top of the skull; the upper jaw sticks out to us. The lower jaw is upright against the wall. In the living animal, above the upper jaw, lies the nose.

Kurzon / CC BY-SA

The sperm whale has the largest nose of any animal in the world. [It also has the biggest brain]. The bulk of that nose is composed of two large, fatty structures, the spermaceti organ and the junk.

At the front of the nose and just inside the blowhole lies an airsac. The left nasal passage is directly connected to the blowhole, but right nasal passage is connected to this airsac. The right nostril is equiped with the socalled the phonic lips, aka monkey lips. These can make noises like this: (you make noise). The sound waves go backward and reflect on the crest. Then they pass through this row of lenses in the junk. That way they emit powerful sound waves that propagate themselves forward hrough the water. These can be reflected by an object such as a giant squid. The reflected sound waves are picked up by the lower jaws and passed on to the auditory organs. These lie directly behind and against the lower jaw. This way the sperm whale is able to localize prey.

Where goes the tail of the whale?

We're going down now, all the way to the ground floor