<h1 class="pgc-h-arrow-right" data-track="1" how do the nostrils of > whales get to the top of their heads? </h1>
Whales are not fish, but mammals that live in the ocean, so they breathe air through their lungs, just like we do. Common mammalian nostrils grow in front of the head, but whales have nostrils on the top of the head, how do they do it?
Today's cetaceans are divided into baleen whale suborders and toothed whales, and their nostrils are invariably grown on the top of the head, rather than the front end of the head.
We all know that the ancestors of cetaceans were small mammals that lived on land, and after they entered the ocean, they underwent more than 50 million years of evolution, and eventually became the most common and diverse family of marine mammals in the ocean today, including not only giant blue whales, bowhead whales, sperm whales, but also various dolphins.
Cetaceans in the ocean today, image from the web
Pakistani whales (Pakicetus) are one of the earliest known cetaceans, an animal that lived 50 million years ago and looks like a dog, with long limbs and hair. Look closely at the Pakistani whale and you'll notice its nose at the tip of its head, just like today's mammals. It is precisely because the nostrils of Pakistani whales are at the front of the mouth that they should swim like today's dogs, always lifting their heads out of the water, and swimming on all fours in a dog-planer manner.
Illustration: Animated image of a Pakistani whale swimming, picture from the Internet
As the cetaceans gradually entered the ocean, their body structure also began to adapt to the direction of marine life, including the position of the neck, the nostrils gradually moved to the top of the head, and their nostrils can be seen in the recovery map of the protocetus and the Basilosaurus below.
Image note: The original whale restoration image comes from the network
Photo note: Dragon King Whale Restoration, Restored By Andrey Atuchin
The ancient whales introduced above belong to the suborder Paleocerider, and the suborder Baleen whale and toothed whale suborder in the ocean today are all evolved from the suborder Paleocercephalus, which appeared in the middle of the Oligocene, about 30 million years ago. Judging from the similarity of the nostrils of today's baleen whale suborder and toothed whale suborder, their common ancestor should have appeared in the nostrils above the head, that is, about before the minke whale suborder and the toothed whale suborder differentiated from the ancient cetacean suborder, cetaceans have completed the process of moving the nostrils from the front of the mouth to the top of the head, a process that lasted for about 20 million years, which is actually quite long.
Illustration: Schematic diagram of the evolution of the suborder Paleocidate, picture from the network
Illustration: Schematic diagram of cetacean evolution, picture from the network
Cetaceans moving their nostrils from the front of their mouths to the top of their heads are not just about changing their position, today's terrestrial mammals have a common esophagus and trachea, so if our nose is blocked because of a cold, we can also use our mouths instead of nostrils to breathe. In addition to breathing, our nose also has the function of smell.
Cetaceans are different, due to changes in the position of their nostrils and changes made to adapt to marine life, the trachea and esophagus are separated, the nostrils are connected to the lungs alone, and the esophagus is connected to the digestive system, so the cetacean nose is only used for breathing but not for smelling.
To better live in the ocean, the nostrils of cetaceans on the top of their heads are indeed more efficient and safer than those located at the front of their mouths. Even above the head, when the whales dive into the water, the nostrils will still be submerged, how to ensure that they will not choke on water? In fact, there is a set of strong muscles under the nostrils of cetaceans, which can completely close the nostrils when cetaceans dive to avoid the risk of choking water, and the separation of the esophagus and trachea also ensures that the cetaceans will not choke on water when they hunt in the ocean, and the most they can do is to drink some seawater in the stomach.
Image note: Baleen whale's large nostrils, picture from the internet
Image note: Blue whale diving into the water, picture from the network
It was by moving the nostrils to the top of the head and a series of other changes in body structure that the cetaceans adapted to life in the ocean and became the most successful family of marine mammals!
Finally, two tips on cetacean nostrils:
First, all suborder baleen whales still have two nostrils, while all suborders have only one nostril left;
Second, we usually see cetaceans surface to spew water column is not the water in their noses, but the water left in the nostril "pit" formed under the action of the high-speed ejected airflow, which is also to avoid these waters entering the nostrils and improve respiratory safety and efficiency. However, the water column produced by the cetacean respiration once posed a great danger to them, and sailors in the whaling era often relied on the water column to determine the orientation of the whale group.
Caption: Killer whales belonging to the toothed whale suborder have only one nostril, and the image comes from the web
Photo note: Gray whales belonging to the baleen whale suborder spray water with a pair of nostrils, image from the internet
Image / Network (Intrusion and Deletion)
Text / Jiang's Little Thief Dragon (Jiang Hong)
Typography / Jiang's Little Thief Dragon