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Most mammals have fur, but some have very short hair, including humans. The reasons for short hair are unclear, but for marine mammals, it helps with swimming, and for naked mole rats, it’s due to their underground lifestyle. The reason for human hair loss is unknown, but some theories suggest it’s related to a semi-aquatic lifestyle or regulating sweating. More research is needed.
Most of the 5,400 mammal species are covered in hair thick enough to be called “fur” – both marsupials and placentals are usually covered in a thick coat of fur, which helps keep them warm. Obvious examples are kangaroos, mice, bears, cats and dogs.
Some mammals have hair so short that when you look at it from afar, it’s not noticeable. Only when you look closely does it become apparent that they are just very short-haired mammals. Examples of mammals with very short hair include elephants, rhinos, cetaceans (whales and relatives), the naked mole rat, and us humans. In particular, the human among mammals with very short hair has caused quite a bit of controversy, with some creationists arguing that the human absence of long hair is evidence that we were created by God as an entity fundamentally different from the rest of the animal. kingdom.
Even to evolutionary biologists, the reasons why hair becomes so short that it practically disappears is unclear and the subject of much controversy. For marine mammals, like whales, the reason seems clearer: to be slimmed down for swimming. The naked mole rat is one of the mammals with very short hair due to its underground lifestyle. Although the naked mole rat has some long hairs for sensory purposes, most of its skin is relatively hairless, giving it the name “naked”.
The most controversial of the very short-haired mammals is, of course, man. Why did humans lose most of their hair about a million years ago? Currently nobody knows. Some scientists believe that the earliest members of the genus Homo, from which humans evolved, spent so much time in water that they developed various adaptations for a semi-aquatic lifestyle, including short hair and increased subcutaneous fat. Others believe it had something to do with regulating sweating. Overall, more research and theories are needed.
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