Morphed races are products of teratogenesis. This type of magic is basically an inheritable form of shapeshifting. As such, the morphed people are biologically human, but transform in-utero into their altered form. Morphed races can theoretically interbreed with each other and with normal humans, although some cultures consider this taboo. When such interbreeding occurs, the offspring inherits form from its mother.
Most morphed races have both human and animal features, and thus resemble shapeshifters such as werewolves in form; the main difference is that the morphed races are permanently fixed into a single form, rather than transforming under some set of conditions. The animal in question is usually chosen for some ability that exceeds human norms. Thus, half-cat forms give agility and night vision, half-dog forms give stamina and keen sense of smell, and half-bear forms give strength. Naturally, there are far more animals to draw from than those with terrestrial analogs, however, this covers some of the more common morphed race varieties.
Because of generations of antagonism between morphed races and normal humans, most morphed races have cultivated noteworthy fighting skills. Due to their lack of central government, however, they do not generally form morphed armies but instead are hired out as mercenaries by their normal human neighbors.