Animal of the Week, January 26, 2016 — sperm whales

A sperm whale washed up at Beverwijk in the Netherlands in the 1600s

Bloody typical, you wait for a sperm whale (Physeter macrocephalus) to come along and five come along at once. The east coast of England has seen five of the magnificent beasts stranded this week, all dead on discovery but likely beached alive. And these five come just a week after another 12 washed up on the shores of Germany and the Netherlands.

As an adolescent I was drawn to them by their delightfully suggestive name—not actually named for some prodigious testicular function, their names comes from spermaceti, an oily substance that fills their bulbous heads and was once highly prized for use in cosmetics manufacturing, leather production, and for making candles. The demand for spermaceti was so great that sperm whales were one of the most highly prized species in the whaling industry of the 1800s, as immortalised in the Melville classic Moby Dick, which I love.

But there are many other fairly stupendous things about these animals—the largest animals with teeth alive today, the whales bigger than them (blue, fin, and bowhead all lack teeth and use baleen plates to obtain food). They are also some of the deepest diving whales, regularly diving over 2000 metres in search of giant squid and colossal squid (its preferred prey). You may wonder how an animal with such a bulbous head would dive so deep, but during dives the spermaceti becomes solid, reducing in volume and streamlining the whale.

Sperm whales have the largest brains of any animal and are the loudest animals on the planet. When hunting, sperm whales use a pair of lips inside their head (known as monkey lips) to generate clicks that are focussed through the spermaceti organ to enable precise echolocation of their prey with sounds reaching up to 230 decibels—a jet engine at take off comes in at a mere 150 decibels (loud enough to cause ear rupture). It's possible that these incredibly loud clicks are used to stun the squid, octopus, and rays the whales hunt.

No one really knows wherefore these strandings occurred—people have speculated links with shipping, sonar, even wind farms, but potentially its nothing half so sinister and just an unfortunate accident. The pod of young male whales made a wrong turn into the north sea and as they headed into the shallower waters they became confused, disorientated, hungry, and eventually dehydrated. Perhaps a little panicked and confused they strayed far too close to shore and once trapped on sandbanks little could be done, as with such large whales, once out of water their great mass (males up to 45 tons) crushes their internal organs.

Sad that at least 17 young males have died in the North Sea, yes. But I always say, you don't see dead animals if there aren't live ones around: so strangely a good sign that there are healthy populations around the British Isles and further out in the deep oceans, making one hell of a racket and dining on the largest calamari there are.