Grey cat raises 4 red squirrels. Why?

This grey feline mother living in Crimea readily took on the burden of raising four red squirrels. It makes a nice video but why did she do it so uncomplainingly?

It seems odd and strangely altruistic for a mother cat to give her time and energy to raising the young of a different species. Might it not have a detrimental effect on her kittens because her efforts are spread more thinly? Might it jeopardise their survival? So why does this grey cat unflinchingly mother four red squirrels?

Does she actually realise that they are not kittens? That’s the first question because if she can’t tell the difference between her kittens and baby squirrels it would explain her behaviour to a large extent.

A study answers that question because it demonstrated that mom cats can distinguish between their biological offspring and other species. They can tell by the difference in the smell of the species.

“…mothers were able to distinguish between the odours of their own and alien kittens…” – Study: Can but don’t: olfactory discrimination between own and alien offspring in the domestic cat.

So why does she do it? It seems that there are two reasons (a) mom cats are not that bothered in raising a baby of another species and (b) instinctively she will raise the kittens of another female cat because her altruism is likely to be reciprocated and so aid survival. And also there is a good chance that kittens who are not hers are related to her in any case. This behaviour seems to be so hard-wired to the extent that it allows her to raise squirrels.

To me, and this my personal view because I don’t think I can find the answer elsewhere, this is about a mom cat being ‘programmed’ to give her time and energy in this way in the interests of overall survival and the fact that she raises squirrels is a minor issue to her.

P.S. Sometimes videos fail to work because YouTube in all their wisdom delete them. If that has happened on this page I am sorry.