Discovered human beings once had two tails

People in evolution have lost their tails. However, a recent study shows that we have lost the tail, not just one but twice.

This finding is published in the American journal Current Biology. Not only does it help explain why we don't have a swinging tail like a dog, a cat or a monkey . but the study also sheds light on why we all have a coccyx and start life with one The real tail gradually disappeared.

" Fleshy tail tails appeared very early in our first vertebrate ancestors and were found in several-week-old embryos, so it would be very difficult to remove them completely." As a result, both fish and humans grow stunted, leaving a tail that is as degraded as the whale's feet , " said Lauren Sallan.

Find out about this mysterious tail-tale origin that brings us back to the fish. In this study, Sallan, an assistant professor at the University of Pennsylvania, analyzed a 350 million-year-old Aetheretmon fossilized fish . The distant ancestors of terrestrial animals today have both a meat tail and a flexible tail fin in another location.

The distant ancestors of terrestrial animals today have both a meat tail and a flexible tail fin in another location.

Sallan found that these structures were completely separate. By comparing the young Aetheretmon with the fish that live today, she found that the two "tails" began to come out from another peak and then develop separately. This finding upset the scientific belief that existed for more than two centuries that the modern large fin-finned fish simply added the end of an ancestral tail to the terrestrial animal.

This interruption means that these two tails go on their own two evolutionary paths. Fish lose their tail and retain their tails flexibly to improve their swimming ability. Only the fin is held to allow the fish to move more smoothly, while a muscular tail will interfere with swimming.

The fish have evolved to become amphibians and then land animals have lost their flexible fins behind, but still retain the "lump of meat" , over time becoming the familiar appendages we found on dogs, cats, cows and many other animals. Like dogs, for example, the tail is very useful in communicating, chasing insects and some other functions.

Adult gibbons, including human ancestors, carried out the process of tail loss a step further. Sallan said: "The loss of bone tail helps better straight movement. Like fish, the remnants of a bone tail in the embryo in the lower position, are coccyx , do not develop due to loss of signals. molecules (if this doesn't happen, it can grow as long as an arm or leg.) Thus, human embryos and fish have the same mechanism to control tail formation. "

The fossil record of early primates collected is usually not large, but from the time the ape lost its tail, Sallan said that our primates' ancestors lost their tails as they began to walk on their legs. Monkeys that often go this way have stunted, underdeveloped tails that continue to prove that the tail can hinder movement when standing upright.