Baby Fae body began generating isohaemagglutinins, but a suitable donor could not be found in time. Prior to the procedure, no infant heart transplant—even with human hearts—had been successfully performed due to a lack of infant human hearts. To address this issue, Bailey had become a pioneer in the research of cross-species heart transplants, which had included "more than 150 transplants in sheep, goats, and baboons". Multiple surgeons had previously experimented with baboon heart implants, leading some to speculate even that baboons could be farmed in the future for such purposes. When asked why he had picked a baboon over a primate
Chacma baboon baboon, averaging slightly higher in mean body mass, and of similar weight to the more compact mandrill, the males of which weigh on average about more than a chacma baboon, the females weigh less than the female chacma. While the mandrill is usually crowned the largest of all modern monkeys, going on total length and average (but not maximum) body weight between the sexes, the chacma baboon appears to be the largest extant monkey. The chacma baboon is generally dark brown to gray in color, with a patch of rough hair on the nape of its neck. Unlike the males