Such hybrids are called tions and ligers. Do they challenge the definition of species? Not really. The key words are "interbreed successfully"; tigons and ligers generally are sterile and short ...
Zorse: A cross between a male zebra and a female horse, Zorses are typically smaller than both zebras and horses, and they often inherit a mix of traits from both parents. Leopon: A cross between ...
A zebra and horse hybrid. Zorses usually have a horse's body with zebra-like stripes. A hybrid between domestic cattle and American bison (buffalo). Beefalo are bred to combine the hardiness of bison ...