QuestionNorth American river otter
How Long Can Otters Hold Their Breath? Otter Diving Facts
Most otter dives last less than a minute, but otters can hold their breath much longer when they need to. North American river otters can stay underwater for up to about 8 minutes, while Eurasian otters usually surface within a minute and are credited with dives of up to about 2 minutes.
Contents
Typical dive times for different otters
Otters hunt with many short dives rather than a few long ones. They search the bottom, chase a fish or grab a crayfish, then pop up to breathe, eat or rest before diving again.
| Otter | Typical hunting dive | Longest dives usually cited |
|---|---|---|
| North American river otter | Well under 1 minute | Up to about 8 minutes |
| Eurasian otter | Well under 1 minute | Up to about 2 minutes |
| Sea otter | About 1 minute | Up to about 5 minutes |
The maximum figures are rare, extreme dives. They show what an otter can do, for example when hiding from danger or searching under ice, not how long it usually stays down. For a hunting otter, short dives are more efficient, because each trip to the surface refills its oxygen store quickly.
How deep do otters dive?
River otters mostly hunt in shallow water. Studies of Eurasian otters along the coast of Shetland in Scotland found that they foraged mainly in water only a few meters deep, close to shore, where fish and crabs hide among seaweed and rocks. The North American river otter is reported to reach depths of around 18 m (60 ft).
The sea otter is the deep diver of the family. It usually feeds in fairly shallow coastal water but can reach about 100 m (330 ft) when searching the seabed for clams, crabs and sea urchins.
How otters are built for diving
Several features help otters work underwater:
- Closing nostrils and ears. Small muscles seal the nostrils and the short ears fold shut when the otter dives.
- Whiskers. Long, sensitive whiskers detect the tiny water movements made by fish, letting otters hunt in dark or muddy water.
- Clear inner eyelid. A nictitating membrane covers the eye like swimming goggles.
- Webbed feet and a powerful tail. River otters swim by undulating the body and tail and paddling with webbed hind feet.
- Waterproof fur. A dense underfur traps a layer of air that keeps the skin dry and warm.
Air trapped in the fur and lungs makes otters buoyant, so they have to swim actively to stay down. That is one reason their dives are short. Unlike seals, which can stay underwater for many minutes, otters store relatively little oxygen in their blood and muscles.
What happens in an otter’s body during a dive?
Like other diving mammals, otters slow their heart rate when they submerge. This reaction, called the dive reflex or diving bradycardia, reduces the amount of oxygen the body uses and sends blood mainly to the brain and heart. When the otter surfaces, its heart rate jumps back up and it quickly reloads its lungs with fresh air.
Cold water is the otter’s main challenge. Otters have no thick blubber, so they rely on their fur and on a very high metabolism, burning energy fast to stay warm. A Eurasian otter needs to eat roughly 15% of its body weight each day, and long or frequent dives in cold water cost a lot of energy.
Why do otters make such short dives?
Short dives suit the way otters hunt. Their prey, such as small fish, crayfish, crabs and frogs, usually hides close to the bottom in shallow water, so an otter does not need long to reach it. A quick search, a grab and a return to the surface keep the otter’s oxygen use low and let it check for danger between dives.
Otters also often eat at the surface. A river otter may float briefly to chew a small fish, then dive again, or carry a larger catch to the bank. Sea otters bring food up and eat it while floating on their backs, sometimes cracking shells against a stone resting on the chest. Every trip to the surface is a chance to breathe, so long breath-holds are seldom needed.
Hunting under the ice
In winter, North American river otters keep hunting in frozen lakes and rivers. They swim under the ice from one breathing hole to the next, using cracks, holes near beaver lodges and pockets of air trapped between the ice and the water. This is one situation where longer breath-holds are useful.
Otters compared with other diving animals
Otters are good divers for their size, but they cannot match true marine mammals. Seals, sea lions and whales have far larger oxygen stores and can stay underwater for many minutes, and in some species more than an hour. For comparison, read How long can seals hold their breath?.
The otter’s strategy is different. It is a quick, agile hunter of shallow water that relies on speed, sensitive whiskers and many short dives. That approach works well in rivers and along coasts, from Alaska to the rocky shores where Eurasian otters hunt among the seaweed.
Frequently asked questions
Can otters breathe underwater?
No. Otters are mammals with lungs, so they must come to the surface to breathe. They hold their breath during each dive and close their nostrils and ears to keep water out.
How deep can a river otter dive?
North American river otters are reported to dive to around 18 m (60 ft), but most hunting happens in water only a few meters deep, close to the bottom of rivers, lakes and shallow coasts.
How long can a sea otter hold its breath?
Sea otters usually dive for about a minute, sometimes a few minutes, with a maximum often given as around 5 minutes. They can reach depths of about 100 m (330 ft) but usually feed in much shallower water.
Do otters sleep underwater?
No. River otters sleep on land in dens and resting places. Sea otters sleep floating on the surface, often wrapped in kelp, with their noses above water.
Can otters hold their breath longer than humans?
An otter's longest dives are longer than most untrained people can manage, but its normal hunting dives of under a minute are short. Otters rely on many quick dives rather than a few long ones.
Sources and further reading
- Animal Diversity Web (University of Michigan), "Lontra canadensis"
- Animal Diversity Web (University of Michigan), "Lutra lutra"
- Kruuk, H., Otters: Ecology, Behaviour and Conservation (2006)
Cite this page
“How Long Can Otters Hold Their Breath? Otter Diving Facts.” Animal Atlas, https://animals.bigworldlist.com/questions/how-long-otters-hold-their-breath/.
