People’s wounds are treated much more slowly than other mammals “

Watching a wild paddled in Kenya, Akiko Matsumoto-Doda, an evolutionary biologist and a primatologist from the University of Ryukyus in Japan, took place in the first place between violence between these monkeys, especially men.

“I was struck by how often they suffered injuries,” she said, “and even more so how quickly they recovered – even from seemingly stern wounds.”

Compared to her own experiences with Nicks and cuts, the ability to cure peacocks seemed to be a superpower.

IN test Published on Wednesday at Proceedings of the Royal Society B dr Matsumoto-Doda and her colleagues compared the indicators of the treatment of people, chimpanzees, monkeys and mice. They discovered that human wounds lasted more than twice as long to treat themselves as wounds of any other mammals. Our ponderous healing can be the result of an evolutionary compromise that we made a long time ago, when we dropped the fur in favor of a naked, sweaty skin that keeps us cool.

If possible, scientists wanted to study treatment in a way that was less violent and more controlled than watching wild peacocks.

To measure the healing of people, they recruited 24 patients who removed skin tumors at the University of Ryukyus hospital. To collect data on chimpanzees, which are one of our closest animal relatives, scientists observed five chimpanzees at Kumamoto’s sanctuary at Kyoto University Wildlife Research Center, which houses animals previously used in pharmaceutical studies. The wounds of chimpanzees, like the wounds of wild pavs, came mainly from tiffs between animals.

Other Supreme Research, all stored in the Kenya Institute of Primate Research, included olive peacocks, Sykes monkeys and Vervet monkeys. Scientists anesthetized monkeys, surgically hurt them and then monitored their recovery. “As an off-road researcher, I personally think that invasive research should be minimized as much as possible,” said Dr. Matsumoto-Doda, who noticed that wounds of bite wounds are often similar to surgical wounds in the study, but deeper.

Finally, to compare people and primary with more distance mammals, scientists anesthetized and surgically injured mice and rats.

Based on its field observations, Dr. Matsumoto-Advent was prepared for people to heal slower than other animals. On average, 24 people arouse skin about a quarter of a millimeter a day.

What surprised Dr. Matsumoto-Doda was the consistency between animal healing indicators, including chimpanzees. There was no significant difference in the rapid growth of the skin among the various primary, which grew by about 0.62 millimeters of novel skin a day or between primary and rodents. People were clear protruding values.

Elaine Fuchs, a biologist of stem cells from Rockefeller University, who examines the growth and repair of the skin and was not involved in novel research, said that the results were what she would expect. This is because the healing of the skin depends on the hair.

Every hair grows out of the hair follicle, which also has stem cells. Usually these stem cells simply make more hair. But when they are called, they can grow novel skin instead. “When the epidermis is wounded, as in most types of scratches and scratches, in fact the stem cells of the hair membranes repair,” said Dr. Fuchs.

Fur animals are covered with follicles, which aid quickly up close to mice or monkeys. For comparison, “human skin has very hair follicles,” said Dr. Fuchs. Our ancestors have lost many of these follicles, instead packing the skin in the glands of sweat. Dr. Fuchs said that sweat glands also have stem cells, but they are much less effective in repairing wounds.

Why did we make this trade during evolution, giving up such a huge amount of hair and their protective properties? The glands that make watery, salty sweat suppress our shirts on a balmy day, are called ecological glands. Most fur mammals have them only in some places, mainly the soles of their paws. But the human ancestors went to sweat-closure people have millions of sweat glands on our bodies and are nearby 10 times denser than those of chimpanzees.

“We have evolved to frosty, he sweats abundantly,” said Daniel Lieberman, an evolutionary biologist from Harvard University. Dr. Lieberman said that our copious sweat glands and lack of fur allow our ancestors in physical activity in balmy environments and cooled the machines of our great brains.

The benefits of hair trading on sweat had to exceed the costs. Dr. Matsumoto-Doda and her co-authors speculate that social support among prehistoric people could aid wounded people stay alive, despite our slower healing. (Or maybe they had ways to treat wounds, as orangutans and chimpanzees seem.)

“The evolutionary disadvantage is that wound healing is slowed down,” said Dr. Fuchs, but people also gained an evolutionary advantage, losing their hair.

“They can put on a coat if they need,” she added.