The Whales breathe By the lungs, which is why they usually rise to the surface of the ocean to take in air. It is important to note that, because whales live in the oceans, many people consider them to be fish.
However, whales are actually mammals. Mammals are a group of animals that breathe their lungs, stop their offspring (unlike other animals that lay eggs) and feed them with breast milk.
There are approximately 80 species of whales, which are divided into two suborders, taking into account the anatomy of the species: bearded and toothed whales.
The barbados are the largest of the two suborders and have no teeth, but beards (hence the name), which are thick bristles. These whales are born with two spiracles, holes that they use to breathe.
For their part, the teeth are smaller and have teeth. These whales have only a blowhole to breathe. Some scientists believe that the toothed whales transformed one of their spiracles into an echolocation system.
Spiracles and breathing
The word"spiracle"comes from Latin Spiraculum , Which means"vent." Spiracles are special orifices that count some animals to breathe. The whale's spiracles are located on the top of their heads to facilitate their breathing and connect directly with their lungs.
These spiracles act as a path to the trachea, allowing air to pass into the lungs.
The location of their spiracles makes the whales can breathe practically without having to strain because they can rest on the surface of the ocean and capture the oxygen needed to live.
When whales swim underwater, the muscles around the spiracle contract to prevent water from reaching the lungs.
It should be noted that whales can not breathe through the mouth, since the trachea of these animals is not connected to their esophagus. This division is important, since having separate ducts to eat and breathe prevents the respiratory system from being blocked by food remains.
In addition, this division allows whales to be able to eat underwater, without having to worry about their lungs filling with water.
The blowhole is a hole in the top of the whale's head that allows you to breathe / Photo retrieved from dkfindout.com
The lungs of whales
To survive underwater, whales have developed special lungs that allow them to inhale extra oxygen and transfer it to blood vessels where it can be harnessed by the body.
According to some researchers, whales are able to use up to 90% of the oxygen they inhale, compared to humans who only use about 15% of the inhaled oxygen.
As for the time that the whales can hold the breath, this varies according to the species and the size.
Some can hold the air in the lungs for a few minutes, 5 or 7, so they must rise to the surface constantly. Other species can hold their breath for 100 minutes, or even longer.
Methods to conserve oxygen
Less effort, more oxygen
Whales use as little effort as possible to swim. When they are submerged, blood is transported only to those parts of the body that need oxygen: the heart, the brain and the muscles they employ at all; In this way, conserve oxygen for longer.
Bradycardia
Whales lower their heart rate, a process known as bradycardia, to reduce the amount of oxygen consumed.
High tolerance to carbon dioxide (CO2)
Whales have a high tolerance to carbon dioxide (CO2), much higher than that of any other mammal; This allows them to dive into the ocean for longer.
Breathe with conscience
Whales are considered conscious breathers, since they strive as little as possible to swim and hunt in order to conserve oxygen.
In addition, these animals never fall asleep completely, since losing consciousness for a long period of time could mean death by suffocation.
During rest, half the whales' brain sleeps, while the other half remains alert so they can act quickly if they need oxygen or have to flee from predators.
In this sense, whales seldom reach the state of deep sleep characterized by rapid eye movement (MOR).
Respiratory process
1 - The muscles around the whale's spiracle contract and open when they ascend to the surface of the ocean, exhaling carbon dioxide. When the whales have long been submerged, it is common to see them expel water through their spiracles, showing that they are exhaling.
2 - The fresh air is inhaled and, later, the muscles relax, closing the spiracle and preventing the passage of water.
3 - The air travels through the pharynx, larynx, trachea and finally reaches the lungs.
4 - The oxygen is transported to the blood through blood vessels located in the lungs.
5 - The heart pumps oxygenated blood to the parts of the body that require oxygen.
References
1. Zagzebski, Kathy (2009). How do whales breathe? Retrieved on April 19, 2017, from nmlc.org.
2. How do whales breathe? Retrieved on April 19, 2017, from whalefacts.org.
3. Can whales breathe underwater. Retrieved on April 19, 2017, from whalefacts.org.
4. How do whales and dolphins sleep without drowning? Retrieved on April 19, 2017, from scientificamerican.com.
5. How do whales breathe? Retrieved on April 19, 2017, from dkfindout.com.
6. Animal Respiration: Whale. Retrieved on April 19, 2017, from animalrespiration.weebly.com.
7. Scientist capture images of sleeping whales. Retrieved on April 19, 2017, from telegraph.co.uk.