What happens when related species interbreed?

It depends on how closely related the two species are, every specie has a different amount of chromosomes in their cells except the sex cells! e.g. Humans have 46 chromosomes in each cell. If you tried to cross a cat with a dog it would not work as they both have a number of chromosomes that are not similar enough. However if you cross a horse with a pony then this will work as they have a similar number of chromosome's, the baby is called a mule. However cross breeding is very hard and the baby will be infertile ( they cannot breed) this means that is you have a dog that is half poodle half Labrador then do not bother getting him or her spayed/neutered as they cant have baby's already! Hope this helped if you want and more help on animals then contact me at charlotte.beard@Yahoo.co.uk