From its bulbous head to its spade-like flukes, the sperm whale is built for deep sea diving. The flukes, or tail, propel the great animal into the murky depths at a rate of one meter per second.
In a world without sunlight, it uses echolocation to find its way around the deep sea canyons and seamounts, and to locate its prey.
The sperm whale can hold its breath for up to 90 minutes. To conserve oxygen, it decreases its heart rate while redirecting blood to the brain and essential organs. Its flexible ribs allow for its lungs to collapse as water pressure increases; this lets the sperm whale dive even deeper. As it reaches 1,000 meters, where it does most of its hunting, the sperm whale reaches natural buoyancy.
Until recently, some scientists thought the sperm whale stunned its prey with loud clicks, or possibly waited motionless with its mouth open like a deep-sea angler fish. Acoustic tagging in 2004 revealed that the sperm whale is actually an active hunter, prowling its environment in search of prey.
When it surfaces, the sperm whale spouts repeatedly to expel de-oxygenated air. It must rest for at least eight minutes before diving again. Once its blood has been re-oxygenated, the sperm whale arches its back, flicks its massive flukes skyward and dives again.