How Deep Can Whales Dive? Sperm Whales and Record Divers

Deepest-diving whales at a glance

How deep a whale dives depends on what it eats. Whales that hunt squid and fish in the deep sea make the longest, deepest dives, while baleen whales that eat krill and small schooling fish mostly stay much nearer the surface.

Record dives are rare exceptions. They show what an animal can do, not what it does every day. The bird records are covered in How deep can penguins dive?

How deep do sperm whales dive?

The sperm whale is the deep diver most people know. A 2006 study using digital tags on 37 sperm whales in the Atlantic, the Gulf of Mexico and the Mediterranean found that the whales’ deepest dives averaged about 640–990 m (2,100–3,250 ft), depending on the region. A typical dive cycle was a 45-minute dive followed by about 9 minutes at the surface, and the whales spent more than 70% of their time in this cycle.

Deeper dives happen too. Sperm whales have been recorded below 2,000 m (6,600 ft), and a maximum of about 2,250 m (7,380 ft) is often quoted. A sperm whale caught off South Africa after a dive of nearly two hours had bottom-dwelling sharks in its stomach, a clue that it had reached the seabed in very deep water. That is an inference rather than a measurement.

Sperm whales hunt squid in the dark by echolocation. Tags show that they start clicking early in the descent and, in the 2006 study, made about 18 rapid “creaks”, or buzzes, per dive on average, each one probably an attempt to catch prey.

Cuvier’s beaked whale: the record holder

Cuvier’s beaked whale is a medium-sized, rarely seen whale about 4.5–7 m (15–23 ft) long that lives far offshore in deep water. In a study published in 2014, scientists used satellite-linked tags to follow eight of these whales off Southern California for up to three months. One dived to 2,992 m (9,816 ft) and another stayed down for 137.5 minutes, both mammal records at the time. The whales’ deep dives averaged about 1,400 m (4,600 ft) and 67 minutes.

A later study off Cape Hatteras, North Carolina, published in 2020, recorded a Cuvier’s beaked whale dive lasting 222 minutes, more than three and a half hours. Researchers think these whales manage it by having very low metabolic rates and large oxygen stores, and by tolerating the by-products of working without oxygen.

Other toothed whales are impressive divers too. Northern bottlenose whales have been tracked deeper than 1,400 m (4,600 ft), and short-finned pilot whales off the Canary Islands hunt squid at depths of up to about 1,000 m (3,300 ft).

How deep do baleen whales dive?

Baleen whales are giants, but they are not deep divers. Their food, mostly krill and small fish, gathers in dense swarms relatively close to the surface. Feeding blue whales off California usually dive to around 200 m (660 ft) for about 10 minutes, and the deepest dive recorded for a tagged blue whale was 315 m (1,033 ft). Humpbacks mostly feed within the top 200 m (660 ft), although one tagged humpback reached 616 m (2,021 ft).

Their feeding style is the main reason. Each lunge through a swarm of krill, with the mouth wide open, uses a great deal of energy, so baleen whales cannot stay down as long as squid hunters that swim slowly and efficiently.

How do whales survive the pressure?

Water pressure rises by about one atmosphere for every 10 m (33 ft) of depth. At 2,000 m (6,600 ft), a whale’s body is under roughly 200 times the pressure at the surface. Whales cope in several ways:

• Collapsing lungs: a whale’s rib cage is flexible, so the lungs can collapse as it descends. Air is pushed into the stiff windpipe, where little nitrogen can pass into the blood, which reduces the risk of decompression sickness, or the bends.
• Oxygen stored in blood and muscle: deep divers carry only a small share of their oxygen in their lungs. Most is held by hemoglobin in the blood and by myoglobin, a protein that makes their muscles very dark.
• A slow heart: the heart rate drops sharply during a dive, and blood flow is directed mainly to the brain and heart.

These adaptations are not perfect. A 2004 study found bone damage in sperm whale skeletons similar to that seen in human divers with decompression sickness, and it was worse in older whales. Beaked whales that stranded after naval sonar exercises had gas bubbles in their tissues, as described in Why do whales strand themselves? More on whale lungs and blowholes is in How do whales breathe?

How do scientists measure whale dives?

Watching a whale disappear tells researchers nothing about where it goes, so they use tags. Suction-cup digital tags stick to a whale’s back for hours to about a day and record depth, movement and sound, including the whale’s own clicks. They then fall off and float to the surface, where researchers recover them.

For longer studies, scientists use small satellite-linked tags attached to the dorsal fin or back, which can stay on for weeks or months. These send summaries of dive depth and duration to satellites whenever the whale surfaces. Nearly all modern dive records, including the Cuvier’s beaked whale records, come from such tags.