How Do Whales Sleep?

Have you ever wondered, how whales sleep? Mammals, whether they live on land or in the water, have many things in common:

• They give birth to live young
• They need oxygen in the air to survive
• They are warm blooded
• They do not function properly unless the brain enters an unconscious state every so often during periods of sleep or rest

Just like all other mammals, whales certainly need to sleep even though the process of floating, sleeping, and continuing to breathe in the water seems complicated.

Whales have developed a very special sleeping pattern to care for their bodies, get rest, and allow their brain to get enough sleep, all while breathing and swimming.

When land mammals need to sleep, they usually lie down before they enter an unconscious state. Whales could potentially sleep in any part of the ocean, either deep or towards the surface, and it would in fact have no effect on their sleep quality – at least in the short term.

Whales continue to swim while they are sleeping, and like dolphins, they remain close to the top of the water, swimming slowly as if resting. This phenomenon is called “logging,” and it allows whales to remain close to the surface in order to be able to breathe while they sleep. 

By being able to breathe, whales are able to get rest for longer periods of time and allow segments of their brain to enter critical periods of rest, improving their health and brain function.

Whales Still Need to Breathe

All mammals need oxygen to survive, whether they live on land or in the ocean. Humans do not need to worry about controlling their breathing while they sleep, since humans (like most other land animals) breathe involuntarily. This means that humans do not need to think about breathing and plan each breath. 

Although humans can control their breathing if necessary, they can slip into the process of breathing involuntarily and not continue to consciously control the process.

Whales have a special respiratory system that allows them to survive easily on one breath every thirty minutes. This means, however, that a whale cannot be unconscious in sleep for more than thirty minutes, or they would suffocate.

Whales have developed a very unique system that allows them to still breathe while they sleep. They only allow one half of their brain to sleep at a time, and the other half of the brain remains awake and active, controlling the whale’s need to rise to the surface of the water to breathe.

This process is also critical for survival because it means that marine mammals can wake up quickly in order to avoid any kind of predator or disaster. Unlike completely unconscious sleepers, whales are more alert and able to respond to any other oncoming obstacles or problems in their environment.

Research on How Whales Sleep

Scientists still wonder just how whales sleep, and continue to do research on how they sleep. Researchers estimate that marine mammals sleep in this half-conscious state of rest for at least eight hours each day. Scientists use a process called electroencephalography in order to study the patterns of marine mammal sleep in dolphins. 

Electrodes are hooked up to the heads of dolphins or whales in order to measure levels of electricity is in the brain and how it is traveling throughout the pathways. Electroencephalograms, known as EEGs, that are produced from this process show that while sleeping, the brains of marine mammals do in fact rest by shutting down, and the other half of the brain remains active.