How do cats know when to shed their coats?

How do cats’ undercoats know to shed in the spring? I know the obvious answer is “cats who’s undercoats didn’t shed were hotter, less efficient, and hence didn’t reproduce as much”. I’ll accept that, but what’s the reason?

I know plants flower based on day length, but my cats are indoors and probably can’t judge day length very well. The temperature in my apartment is constant most of the year.

An interesting site, puts forward the theory that cats shed in the spring due to an increase in natural sunlight. It says that indoor cats pretty much shed all year round. Any thoughts?

Interesting. My cats do shed year round, but you can definitely tell a huge increase of shedding in Springtime. I definitely see a loss of an “undercoat” in my Maine Coon, and he has only coughed up hairballs in March through May for the last 3 years. Maybe the little sunlight they get through the windows does allow them to synchronize somewhat?

I’ll go with Ice Wolf’s theory.

We were taught that daylength, having an effect on the pituitary ( I think it was the pituitary… some neurosecreting brain part, anyhow :confused: ), causes a whole cascade of events which lead to shedding of the undercoat (and, for my cat, the outercoat too :rolleyes: )

Well, the way it was explained in one of my biology classes or another, animals in the wild regulate breeding cycles, shedding, and other seasonal changes by changes in the photoperiod (amount of time it’s light out). Electric lights muck with this somewhat, with fluorescents being worse than incandescents. These lights don’t have fully the same effects as natural sunlight, possibly related to different UV levels in the types of light. Therefore, your cat sheds somewhat all year round, but a lot more in spring and fall.