Why do male calico kittens die before adulthood? And those that make it – what does that mean for the future health? Do they live less long? Are there any particular problems for them?

ask-drferox:

Mate… they don’t. I don’t know who told you that, but they’re completely wrong.

Tortoiseshell and Calico (which is tortoiseshell plus some white colour on top) is caused by having two different X chromosomes – one with the black colour and one with ginger.

A normal female is XX, so she can easily have both a ginger and a black X, and be a perfectly normal tortoiseshell.

A normal male is XY. He can only be one or the other.

A XXY male can be tortoiseshell, but this is rare and he’s got kleinfelter’s syndrome. They’re pretty normal, but usually infertile and may have a smaller phallus. They don’t just ‘die’, they’re rarely created in the first place.

This post explains it in more detail.

– Dr Ferox.

Animals (including humans) with an extra chromosome generally do okay, though their sexual characteristics may be a bit wonky. Most of the time you’d never know about the chromosome defect, except in the case of animals with visible linked traits, like these cats.