What does color mean in the pets/livestock list?

Solution 1:

Baby animals are red (like dwarven children).

Apart from that each species has their own colour, roughly corresponding to the colour of the animal in real life.

  • Brown: goats, horses, cows, yaks, deer, dogs, kangaroos
  • Grey: buffalo, cats, ravens
  • White: geese, woolly animals (sheep, llama, alpaca)
  • Blue: peacocks (peahens are brown)
  • Green: kea, duck
  • Pink: pigs (sows and boars)

Note that a change in background colour indicates a status effect and has no relation to the species.