geep!

The animal is a crossbreed of two entirely different species, a goat and a sheep. Inevitably, it has been dubbed a geep.
Now 18 months old and thriving, the geep was produced by the latest tricks of embryo manipulation. Scientists at the Institute of Animal Physiology in Cambridge, England, mingled new embryos from both sheep and goats when each consisted of no more than four to eight cells. Ultimately, these were placed in the wombs of surrogate sheep or goat mothers and allowed to grow to term. Such hybrids are called chimeras (after the mythic monster with a lion's head, goat's body and serpent's tail).
Because each embryo came originally from the fertilized eggs of both a goat and a sheep, the animals had four parents.

source: http://www.time.com/time/magazine/article/0,9171,921546,00.html