Why do these animals make faces?
You've seen zebras at the zoo or online sometimes pouting their mouths and showing their teeth in a mocking manner, or tigers sticking their tongues out and making faces like they've eaten disgusting food or just plain dislike you. In addition, you may sometimes find your neighbor's haughty kitty suddenly showing her teeth, revealing her sharp little teeth, as if she is trying to intimidate you. These beautiful animals how good reason hard to mold themselves into "emoticons"? Biologists say it's a phenomenon known as the Freeman reaction, which is also known as cleft lip sniffing.
"Ghost face" in the doorway
Cracked lip sniffing reaction refers to the animal turned up the upper lip, exposing the teeth, to collect external pheromone strange behavior, commonly found in hoofed animals, felines, and elephants, wombats, hedgehogs, pandas and other mammals. Among them, the horse cleft-lip sniffing action of the odd-toed order is particularly large, grinning, as in a big smile, very attention-grabbing. These animals will make this kind of exaggerated expression, mainly due to their bodies hide a special physiological structure - plow nose apparatus.
Animals can not only smell odors with their noses, but also sense them in their mouths. The plough-nose apparatus is the mysterious physiological structure hidden between the mouth and the nasal cavity specifically for the detection of pheromone pheromones. For example, in cats, there are two tiny holes at the root of the front teeth of the upper jaw, which are connected to the nasal plough, and odor molecules are collected from these two small holes and transmitted to the plough to reach the brain. And the animal's turning up its upper lip in a ghostly gesture facilitates the exposure of the small holes in the roots of the teeth to the air, which transmits odors to the nasal plough, which in turn transmits the acquired odors and pheromone information to the brain.
Will you be my friend?
Pheromones, a catch-all term for a range of chemical messages secreted by animals, contain biological signals related to an organism's sex and reproduction. To us, what we can smell may just be some unnameable and strange odor, but to animals, these external pheromones are rich in content and silent language.
Some experts believe that animals produce the cleft-lip sniffing response in some cases to be able to better perceive the pheromones contained in the urine of the opposite sex, a special skill that exists as a result of reproduction. In the case of giraffes, for example, during the search for a mate, a male giraffe will touch a female's buttocks with his head. Some females will respond by showing acceptance by spreading their legs to urinate, triggering a split-lip sniffing response from the male. The male lifts his upper lip, opens his nostrils to inhale, and even tastes the urine to get important chemical signals about whether the "girl" wants to spend the night with him.
Smelling the world
Smelling the split-lipped can help animals better access biological information, which, in addition to mating, is important for dividing up territory and communicating with each other. For hunting animals, cleft-lip sniffing can also help them detect the scent left behind by other animals of the same species or prey. Domesticated animals like cats also react to other odors, such as the occasional smelly sock, but food odors do not trigger a cleft-lipped sniff in cats.
Not all animals with a nose-plow structure have a cleft-lip sniffing response, however. Elephants don't pout and "make faces" because their long trunks get in the way. Instead, they dip their trunks into what they want to know and then roll their trunks into their mouths, which have access to the plastron at the roof of their mouths. If you see an elephant at the zoo sucking up urine through its trunk and shoving it into its mouth, don't blame it for being heavy-handed; maybe it just wants to smell it to see if its buddies are having fun. And while reptiles like snakes and lizards have a distinct plow-nose apparatus structure, they apparently don't have a cleft-lip sniffing response either. They have tiny tubes on their tongues that lead directly to the plastron, so they spit their letters to get information about pheromones.
Do people have a nasal plow?
See, don't be tempted to use your tongue to look for tiny holes in your own palate that lead to the plastron, it's just useless. The human nasal plumbing apparatus is highly degraded, so you hardly notice any difference between breathing with your mouth open and breathing with your mouth closed. The cleft-lip sniffing response isn't something we can all do, and it's probably one of the observational senses that was shed in human evolution. It's clear from modern human growth that our ancestors should have had the cleft-lip sniffing response, and a little trace of it remains in our bodies today.
Physical structures such as the nose-plow actually exist during human embryonic development. After birth, there is a pair of tiny depressions in the lower part of our nostrils that receive external pheromones through the corresponding ducts, and in this way, babies are able to find the source of food through the pheromones emanating from their mother's breasts before their eyes are even opened. As a person grows and his senses mature, this external pheromone-receiving device loses its usefulness and gradually deteriorates. Scientists dissected 564 adult individuals and found that 70 percent of these adults no longer had a nasal plough structure, while the remaining 30 percent had this structure, but the opening of the plough was extremely small and highly degraded, and was unable to perform the appropriate function.
This article is derived from the Big Tech* Science Mystery Issue 5, 2016 article