Horse breed been produced. Such restrictions have led to legal challenges in the United States, sometime based on state law and sometimes based on antitrust laws. Horses can crossbreed with other equine species to produce hybrids. These hybrid types are not breeds, but they resemble breeds in that crosses between certain horse breeds and other equine species produce characteristic offspring. The most common hybrid is the mule, a cross between a "jack" (male donkey) and a mare. A related hybrid, the hinny, is a cross between a stallion and a jenny (female donkey). Most other hybrids involve the zebra (see Zebroid). With
One-male group offspring, compared to a noninbred offspring. Inbreeding depression resulted from the decreased genetic diversity within this population, meaning that the population as a whole experienced a decrease in fitness (i.e. reproductive success). Unlike infanticide, the high occurrence of inbreeding in one-male groups is a disadvantageous to both the females and males in the group. Experiments involving the hamadryas baboon species ("hamadryas hamadryas") provide evidence of feeding advantages for male and female members of one-male groups. However, the findings of feeding advantages were only evident when these one-male groups formed clans. It has been shown that males from single one-male groups