Cats have gotten a good deal out of domestication: They’re safer, warmer and protected from almost all threats. They know where their next meal is coming from, and won’t hesitate to meow our ears off if dinner is late.
But one tradeoff doesn’t immediately appear beneficial: Domestic cats have smaller brains than the species they’ve evolved from, African and Eurasian wildcats.
“[D]omestic cats indeed, have smaller cranial volumes (implying smaller brains) relative to both European wildcats (Felis silvestris) and the wild ancestors of domestic cats, the African wildcats (Felis lybica),” the research team wrote.
Wild cats have the largest brains on average, followed by wild-domestic hybrids and domestic cats with the smallest brains of the three.
That’s another strong indicator that domestication is the determining factor in feline brain size, although the researchers point out that they are comparing domestic cats to current wildcats, and not the ancient population of wildcats from which domestic cats evolved beginning some 10,000 years ago with the dawn of agriculture and permanent human settlements.
Wildcats with friendlier and bolder dispositions were the first to approach human settlements, drawn by the rodents who were themselves feasting on human grain supplies. Humans realized that the cats were taking care of their rodent problems but weren’t interested in eating the grain, and a beautiful partnership was born.
Smaller brains do not necessarily correlate to lower intelligence, however, and cats aren’t the only species whose brains became smaller after they were domesticated. Dog brains are about 30 percent smaller than the brains of gray wolves, but dogs have adapted spectacularly to living with humans and reading human behavioral cues.
“The dog is successful not because of the size of its whole brain per se, but because domestication has led to subtle brain changes with a stunning result: the ability to live in the world of people,” a Smithsonian Magazine article points out, noting dogs are also adept at getting people to do all sorts of things for them.
If brain size alone resulted in higher levels of intelligence, whales and elephants would rule the Earth.
Instead “the complexity of cellular and molecular organization of neural connections, or synapses, is what truly determines a brain’s computational capacity,” neuroscientist Kendra Lechtenberg wrote.
The researchers weren’t interested in drawing any major conclusions about feline cognition with the study. They’re more interested in the phenomena of “domestication syndrome,” which causes changes both physical (floppy ears, coat color variation, shorter muzzles) and behavioral. (Less aggression, playfulness.)
The jury’s still out on why exactly those traits emerge, but some studies have attributed it to differences in embryonic development. Unlike many other domestic animals, cats don’t look much different than their wild felis lybica and felis sylvestris counterparts.
The cat study was published on Jan. 26 to Royal Science Open Science, a peer-reviewed open-access journal. The research team was comprised of biologists from the University of Vienna and data curators from the National Museum of Scotland.