It is well known that sleep is an essential part of animal life and, in fact, it has been shown that under some conditions, lack of sleep is fatal. However, what has not yet been clarified is why some animals sleep more than others. In the case of whales, they are part of a group of mammals that face an unusual and extreme environment in which they must be able to fall asleep, since they spend their entire lives in the water, sowhen they sleep they should avoid drowning Unlike other mammals, whales sleep unilaterally, meaning that only one of their hemispheres falls into sleep processes.
Keep reading this article on our site and learn the fascinating details of how whales sleep, the largest animals that exist today inhabit the Earth.
How do whales breathe?
To understand how whales sleep without drowning, we must first know how these animals breathe. As we said, whales belong to the group of aquatic mammals, which means that, exactly, whales have lungs.
To breathe, whales need to come to the surface to collect air through the hole in the top of their heads, the blowhole. However, the whale's pulmonary system is not connected to its mouth, so whales cannot breathe through their mouthsThis makes it easier for them to feed without water going into their lungs.
How do whales sleep without drowning?
Whales, like dolphins and other aquatic mammals, can rest, either vertically or horizontally, and often let themselves floator sleep while with a partner and swim slowly. On the other hand, they reduce the number of breaths during periods of sleep.
While the rest of the mammals live in a terrestrial environment that allows them to rest almost anywhere, the whales, as well as the rest of the marine mammals (the cetaceans) do not have it so easy when it comes to sleep and be able to rest, since they face three difficulties:
Surface to breathe
But how do whales breathe when they are asleep? Whales, like the rest of the cetaceans, have lungs, so they need to come to the surface to breathe, making it impossible to have deep bilateral sleep, that is, from both hemispheres like other mammals. That is why they choose to alternate sleep between both brain hemispheres.
While they sleep (as well as during diving) the holes for breathing, that is, the spiracles, which are located on the top of their heads to facilitate breathing and are directly connected with your lungs, they are closed while you sleep, preventing water from entering your breathing passages.
Maintain your body temperature
Whales live in an aquatic environment that is thermally challenging. The continuous contact with water supposes a great loss of body temperature by convection, that is, by heat transmission between areas of different temperature. That is why they require a series of both anatomical and physiological adaptations to maintain their body temperature, which translates into an increase in muscle activity and modification of its arterial circulation in order to heat the body. On the other hand, there is an increase in the production of norepinephrine, a brain hormone that causes your metabolism to increase and your temperature to rise.
Keep watch for predators
This characteristic is represented by a curious behavior, which in addition to whales, other species of cetaceans also possess, and is Keep one of its eyes openThis serves both to maintain an overview of the environment, as well as to maintain vigilance and protect themselves against predators or conspecifics (that is, individuals of the same species).
Now that you know that whales sleep so little, you may be interested in learning about these 12 other animals that don't sleep.
Do whales dream when they sleep?
It has been proven that whales have a specific way of sleeping, called USWS (“Unihemispheric slow wave sleep”), for which they maintain the slow waves in one of their hemispheres, while the other hemisphere maintains a minor, low-voltage activity. This means that half of the brain stays awake to make sure it breathes and stays alert for any danger in its environment, while the other half of the brain sleeps.
According to some research, whales when they sleep do not have a REM phase (sleep phase characterized by rapid eye movements, relaxed muscles and is the time when dreams occur) like land mammals and other animals such as birds. However, other scientists affirm through their studies, that whales can have this phase, and in fact, even soñar The difference with other mammals that have REM phase is that they do so for a very short time, approximately 12 minutes, as if it were a mini nap. Due to this strategy, the whales keep in continuous movement. On the other hand, for example, calves (baby whales), can rest next to their mothers, while they swim, propelling them with the waves they produce in the water.
So whales can sleep and, according to some studies, even dream. However, they do not do it in the same way that we humans or other mammals do, but they take short naps that allows them to rest and at the same time be attentive to their environment and potential hazards.
How do other fish sleep?
Now that you know how whales sleep, you may also be interested in these other articles where we explain how other aquatic animals sleep:
- How do dolphins sleep?
- How do fish sleep?
- How do sharks sleep?
