…Thus, the widespread adoption of early neutering by the most responsible cat owners risks pushing the domestic cat’s genetics back gradually toward the wild, away from their current domesticated state.
A study that I conducted in 1999 suggests that such extrapolation cannot be dismissed as science fiction. 15 [John W. S. Bradshaw, Giles F. Horsfield, John A. Allen, and Ian H. Robinson, "Feral Cats: Their Role in the Population Dynamics of Felis catus," Applied Animal Behaviour Science 65 (1999): 273-83. https://www.gwern.net/docs/catnip/1999-bradshaw.pdf ] In one area of Southampton (UK), we found that more than 98% of pet cat population had been neutered. So few kittens were being born that potential cat owners had to travel outside the city to obtain their cats. This situation had clearly existed for some time: from talking to the owners of the older cats, we calculated that the cat population in that area had last been self-sustaining some ten years previously, in the late 1980s.
We located ten female pets in the area that were still being allowed to breed and tested the temperament of their kittens after homing, when the kittens were six months old. Our hypothesis was that feral males must have fathered many of these kittens, since so few intact males were being kept as pets in the area, and all of these were young and unlikely to compete effectively with the more wily ferals. We found that on average, the kittens in those ten litters were much less willing to settle on their owners’ laps than kittens born in another area of the city that still had a significant number of undoctored pet tomcats. There was no systematic difference in the way these two groups of kittens had been socialized, and the mother cats in the two areas were indistinguishable in temperament. We therefore deduced that even if only one of the two parents comes from a long line of ferals, the kittens will be less easy to socialize than if both parents are pets. The study was too small to draw any firm conclusions, but in the years since it was carried out, blanket neutering has become more widespread, and so the cumulative effects of this on the temperament of kittens should be becoming more obvious. Neutering is an extremely powerful selection pressure, the effects of which have been given little consideration. At present, it is the only humane way of ensuring that there are as few unwanted cats as possible, and it is unlikely ever to become so widely adopted that the house cat population begins to shrink. However, over time it will likely have unintended consequences.
It’s interesting how millennia of rigorous and often rather cruel selection is getting reversed in the blink of an eye, across multiple species.
Hopefully they’re not getting bigger. 20 kg feral cats would be legitimately dangerous predators to children.
On the other hand, I wonder if feral cats are also getting more intelligent, to better navigate complex urban environments. This may be happening with respect to Moscow’s dogs, some of whom have figured out how to use the subway.