The sperm whale or Physeter macrocephalus is one of our favorite animals on earth. This fascinating whale is one of the most recognizable with its square-shaped head. It looks like it comes from another world. First, the name, “sperm whale,” resulted from whalers misinterpreting the function of the “spermaceti” oil in the forehead of the whale, and because cooled spermaceti has some physical resemblance to mammalian… you know what.
Everything is fascinating with this whale: from the legend of Moby Dick to the very secretive life of the sperm whales itself, spent mostly deep under the surface.
We will enumerate the aspects of this whale we find the most fascinating:
A deep Dive
First, sperm whales are one of the deepest divers in the world. Diving below 3000ft (1000m) for 45+ minutes is no big deal for this giant. It is deep below the surface that they find the cephalopods they feed on.
Crazy big head
The sperm whale is not the biggest mammal on earth but it has the largest brain with an average of 7.8kg of brain mass in males. Its head represents ⅓ of its total body length (macro=big, cephalus=head), which can reach 20m.
From the surface, they are easily recognizable because their blow direction is diagonal and to the left. It is due to the structure of their asymmetric skull (picture below)
Squid in on the menu
Adult males can eat colossal squid, Mesonychoteuthis hamilton, the largest squid species (in mass) on earth. Their fights with giant squids can result in scars on sperm whale skin.
Ambergris forms in the sperm whale’s digestive tract and is caused by irritation from squid beaks. Sperm whales produce it over the course of multiple years to help with the passing of objects that do would otherwise break down in their digestive tract. Ambergris was heavily used in the perfume industry, but its rarity eventually led to the search for other substances. I had the chance to smell it once and it smells really good.
They have visible teeth on their lower jaw only. The sperm whale has 18 to 26 teeth on each side of its lower jaw which fit into sockets in the upper jaw. The upper jaw has rudimentary teeth (they rarely emerge into the mouth).
You can find a very good and thorough recap of this amazing whale by the most famous sperm whale scientist, Hal Whitehead, here:
Want more whale knowledge? Stay tuned for our June 2020 whale of the month, the North Atlantic Right Whale (Eubalaena glacialis)