Dogs have been domesticated for at least 30,000 years, while cats began to get along with people only about 9,500 years ago. It fits perfectly with your intuition that dogs are always willing to be good companions for humans in any way, while cats are often cold. If you ask a zoologist to explain this, he’ll probably say, it’s simple, because cats are the only semi-domesticated animals.
Today’s wild ancestors of domestic cats are African wildcats. If you put them side by side, it’s hard to tell from the outside: African Wildcats look like tiger-striped domestic cats. If you have to tell the difference, it’s probably that wild cats have longer legs and more cheetah-like gait than domestic cats. This distinction is particularly evident when a cat squats upright. Cats on ancient Egyptian bronzes clearly show this sitting position.
In fact, the range of activity of African wild cats is very close to that of human settlements, so they often mate and breed with domestic cats. The existence of a large number of hybrid individuals makes the boundary between them and domestic cats more blurred. However, if you try to touch them, you can immediately feel the difference in personality. It may be the wild cat that shows a ferocious retreat, and the cat that meows and meows lie down and scratches you must be a domestic cat.
The entry of Miao people into human society took place shortly after the Middle East ancestors began to adapt to agricultural life. Attracted by rats stealing from barns, wild cats, originally living in the desert, slipped into human villages. Among them, the wild cats closest to humans are more likely to be protected and to be served with leftovers, so they gradually settle down in the village.
So, in the nearly ten thousand years of domestication history, what on earth has happened to be noticeable? A paper published in the Proceedings of the American Academy of Sciences in November, comparing the genomes of wild cats, several domestic cats and common mammals, helps us to reveal more about the mysteries of meowing humans, and how other species, including humans, have lost their wildness.
One of the authors of the paper, Michael Montague, started his research on the genome of an Abyssinian female cat after a PhD at the Medical School of St. Louis University in Washington. After comparing the genomes of domestic cats, cats, tigers, dogs and humans, he listed 281 genes with rapidly changing genetic information in domestic cats.
Some of these genes are related to hearing and vision, which explains that cats have a slightly weaker sense of smell than dogs, but a stronger sense of sight and hearing at night, which is also an important skill cats rely on for predation. In addition, cats also have genes associated with perceptual pheromones, which gives them the magic ability to search for prey and heterosexuality over long distances.
In addition, researchers have unexpectedly discovered some genes related to lipid metabolism. Animals like cats and tigers naturally eat only meat, but even if they eat a lot of fatty acids, they will not suffer from high blood fat and heart disease. These genes may exist to adapt to highly carnivorous habits. Unfortunately, they do not exist in humans and cattle, so humans need to eat a large amount of starch and cellulose to balance their diet.
The most interesting finding in Montague’s study was that they compared the genomes of 22 domestic cats, African Wildcats and European wildcats. It was found that at least 13 genes altered the cat’s habits, such as fear response, and the ability to learn new behaviors after being rewarded with food. “That’s in line with what we know about domestic cats,” Montague said. “To adapt to domesticated life, they can’t be too afraid of strangers and new environments, but they can feed back rewards so that they can be fed by humans for a long time.”
“This is my favorite part of the whole study,” said Lindblad, a comparative genomist at Uppsala University in Sweden. Some genes related to glutamate receptors play an important role in learning and memory, and they have been screened for generations in human evolution. “In evolution, humans tend to retain genes that help the brain develop and make people more sociable.”
Montague also found five important genes in domestic cats that affect the migration of crest cells and embryonic stem cells. These genes may explain some of Darwin’s questions: Why do domesticated animals generally have smaller brain-body ratios and specific black-and-white colors?
Black and white flowers are very rare in the wild ancestors of livestock, but they are common in all kinds of animals bred by human beings. This is because the melanocytes that control hair color come from the nerve crest cells. Once the latter mutates in the development process, the pigmentation in the corresponding areas of the animal will be reduced, which appears to be white spots or large patches. The areas most prone to pigmentation deficiency are the areas where the crest cells migrate last, such as under the larynx, above the eyes, claws and the tip of the tail.
When cats are adopted by humans, they don’t have to think too much about how to make a living, nor do they need developed jaws to bite hard-to-access prey, and their brains and heads naturally grow smaller. This trend is the same with dogs. If you take wolves and dogs for an IQ test, you will find that wolves are much smarter than dogs.
In fact, we are also a domesticated animal. According to Conrad, a zoologist and Nobel Prize winner in 1973. Lawrence’s theory is that the evolutionary types of humans are basically similar to those of livestock. Our brain-to-body ratio peaked at the end of the last glacial period, and then declined with the rise of agricultural civilization. Whether humans today are smarter than their ancestors at that time is unknown.
Compared with dogs, the domestication history of cats is obviously not long enough, which is why they are more wild than dogs. William Murphy, a geneticist at Texas A&M University and a research correspondent, said that cats had less evolutionary pressure than dogs during their domestication. In addition to keeping the instinct of catching mice, humans had never deliberately portrayed cats as dogs, cows and pigs. Dogs are competent for caretakers, anti-drug, blind guides and sled pullers. “Cats just wander around, and humans can tolerate them.”
The unfaded wildness of the meows does bring some troubles to the urban ecology. Even domestic cats, who do not worry about food and drink, are keen on killing small mammals, birds and fish. A paper published in the January 2013 issue of Nature Letters shows that stray cats and wild cats have become the top enemies of wildlife. In the United States alone, 1.4 billion to 3.7 billion birds and 6.9 billion to 2.7 billion mammals die each year from cat killing.
Greg Larson, an evolutionary biologist at Oxford University, argues that although this is “the first time scientists have such definite evidence”, it is somewhat unfair to say that cats are semi-domesticated animals. “I have two cats. They lie quietly on the sofa all the year round, ignoring the dogs and primates that walk around, and not worrying about the dangers they pose to themselves. Isn’t that gentle enough for a congenital wild pure carnivore?