Pet cat skulls have gotten significantly smaller over the last 10,000 years, and so have their brains.
However, many studies documenting these morphological variations are more than 40 to 50 years old—and some could use an update. For example, one study published in the 1960s compared house cats to European wildcats, which are not direct relatives of today’s furry feline friends, reports Brandon Specktor for Live Science.
Using modern scientific knowledge, a study in 2022 replicated these early experiments to confirm that domestic cats (Felis catus) do in fact have smaller brains than their ancestors, according to a paper published in the journal Royal Society Open Science.
Pet cats are not dumber than wildcats
Per the Live Science, this doesn't necessarily mean that your tabby is dumber than a wildcat. But, according to one hypothesis, it shows that prioritizing tameness in domesticated animals may have inadvertently changed the ways those animals' brains develop, the researchers said. These changes likely begin when an animal is still an embryo and just beginning to develop its neural crest cells — a special type of cell unique to vertebrates, which plays a key role in the development of the nervous system, among other things.
The research team measured a total of 103 skulls from the collections of National Museums Scotland. They compared domestic cat skulls to African wildcats (Felis lybica), a genetically closer relative than European wildcats (Felis silvestris). To measure cranial volume, they filled each skull with one-millimeter glass beads and weighed how many each skull could hold, per the study.
Modern house kitties have smaller cranial volumes than African wildcats, but both species have smaller skulls than European wildcats. They also measured the skull volume of domestic cats bred with European wildcats. These specimen had brain sizes somewhere in between the small size of their domesticated parent and large size of their wild parent.
The team found that the old research still holds up, with house cats showing as much as a 25% reduction in cranial size compared with African and European wildcats. The researchers also examined a number of hybrid wild/domesticated cat species, and they found that these cranial measurements fit in a perfect middle ground between the wild and domestic species.
These specimen had brain sizes somewhere in between the small size of their domesticated parent and large size of their wild parent.
The researchers wanted to update this study by comparing house cats with the African wildcat, which genetic research has since confirmed to be the closest living ancestor of modern domestic cats.
All this goes to show that domestication has had a significant effect on the evolution of cats over the past several thousand years — a phenomenon seen in many other species of domesticated animals, as well.
SOURCE
LIVE SCIENCE: “Cat brains are shrinking, and it's all humans' fault.”
ROYAL SOCIETY OPEN SCIENCE: “Cranial volume and palate length of cats, Felis spp., under domestication, hybridization and in wild populations.”