The liger is greater than the sum of its parentage

Ligers and wolphins and zorses, oh my!
The New York Times has a great story about hybrid animals and plants, and why those hybrids are sometimes better adapted to survive than the pure species that gave birth to them.

Because species hybrids create new combinations of genes, it is possible that some combinations might enable hybrids to adapt to conditions in which neither parent may fare as well. ... Two widespread species, the common sunflower and prairie sunflower, have combined at least three times to give rise to three hybrid species: the sand sunflower, the desert sunflower, and the puzzle sunflower.
The parental species thrive on moist soils in the central and Western states, but the hybrids are restricted to more extreme habitats. The sand sunflower, for instance, is limited to sand dunes in Utah and northern Arizona and the puzzle sunflower to brackish salt marshes in West Texas and New Mexico. The species distributions suggest that the hybrids thrive where the parents cannot.

That's got implications for humans, as well, given the mounting bits of evidence suggesting that we are not purely Homo sapiens, and, instead, the result of sapiens dalliances with neanderthals and other related species. It's possible that we owe our success as a species to a hybrid nature as hardy as that of any beefalo.