Why are a tiger's stripes still there if you shave it?

The pattern is in the skin as well as the fur. Pigment cells are distributed in the skin itself, so a shaved tiger is still visibly striped - and every tiger's pattern is unique, which researchers use to identify individuals from camera traps without ever touching the animal.

How an animal grows a stripe at all was answered by Alan Turing in 1952, in his last published paper before his death. He showed mathematically that two chemicals diffusing through a developing tissue at different rates, one activating and one inhibiting, will spontaneously settle into regular patterns - spots, stripes, blotches - from a uniform starting state. It was decades before biologists found real molecules behaving that way, and reaction-diffusion is now the standard explanation for markings from zebrafish to seashells.

The stripes work as camouflage in a way that seems unlikely until you consider the audience. Orange looks conspicuous to us because we have three colour receptors; deer and pigs have two, and to them an orange tiger against green foliage is close to invisible. The tiger is not hiding from you. Its prey cannot see the colour it is wearing.