>>3041054>They never show any signs or have any mentions of it?Few shows do that even if they are human. However...
Typically a mammal will have either a menstral or an estrus cycle. The only kammals known to have true periods are humans, apes, old world monkeys, bats and the elphant shrew.
Dogs and other domesticated creatures are known to produced vaginal discharge when ending their eastrus (as oppossed to the normal absorbrion), but this is not a true period.
Birds tend to lay only at certain times of the year except for chickens. Chickens will lay once a day until they have a clutch of about a dozen. If you take eggs away they keep laying until the clutch is full again.
From what I can see, fish and snakes only produce eggs during mating for fertilisation.
Side note: only 70% of snakes lay eggs. Though of the 30 that give birth, some are true internal development while others are just retained eggs until they hatch.
