The largest living toothed animal, the sperm whale (Physeter macrocephalus) is found worldwide and can reach lengths up to 20 metres, although most average at around 15 metres. They are also the largest living predator and hold the award for the biggest brain of any animal! If that wasn’t enough, they are also the second deepest diving mammal after the Cuvier’s beaked whale. The sperm whale is certainly a fascinating and unique creature.
Sperm whales are easily recognisable with their huge square head and comparatively small lower jaw. Their name comes from an organ in their heads which is filled with a waxy substance called spermaceti oil but there is some uncertainty regarding the function of this fluid. Many biologists believe it is used to alter the whale’s buoyancy because the oil hardens when cold, allowing the whale to adjust its underwater altitude. Just before a deep dive, they will display their large, triangular tail flukes in order to propel themselves downwards. During these lengthy dives, they must hold their breath for approximately 90 minutes.
As the world’s largest predator, their diet mainly consists of medium-to-large sized squid found deep in the ocean. These whales use echolocation to target their prey and also for communication with other sperm whales. It is thought that these whales may occasionally collaborate during hunting. Sperm whales are highly social creatures, living in pods with around 20 individuals including females and their young whilst male sperm whales usually live solitary lives.
Sadly, these highly intelligent and majestic creatures are considered vulnerable by the IUCN, primarily due to mass sperm whaling between the eighteenth and twentieth centuries which led to the slaughter of hundreds of thousands of sperm whales. Thankfully, the demand for commercial whaling has drastically fallen and sperm whales are protected across the globe. We still have so much more to learn about these magnificent mammals.