And howsoever the matter we speak of is abominable, yet it is not fruitlesse, but helps much to the knowledge of some other things in the searching out of the secrecies of nature.
—Giambattista della Porta
Natural Magic, 1658
Many people are convinced that human hybrids, that is, hybrids involving human parentage, do not exist (other than ancient hybridization between various members of the genus Homo) and that they cannot exist. But it’s a head-in-the-sand mentality, given that there is actually quite a bit of evidence to the contrary (multiple eyewitness reports, videos, and even specimens). Perhaps it’s just that many people feel more comfortable denying the very possibility of such things than they do discussing the evidence of their existence. Obviously, the manner in which such things would come into being, would involve acts that would violate longstanding cultural and ethical taboos, something that most people simply do not wish to talk about. And yet, such information has great relevance not only for biology, but for humanity as a whole.
As indicated by the reliability arrow, the various types of human hybrids listed at right occupy a continuum between fact and myth. Some, such as pig × human or cow × human are closer to fact. Others, like bear × human and horse × human lie closer to myth.
For a long time only the bears and birds were at the berry thickets and the rivers. The humans arrived later. At first they all got along. There was always a bit of food to share. Small animals might be as powerful as big ones. Some, and a few humans, could change skins, change masks. From time to time they all would cross into the spirit world for a Big Time or a contest. The humans beings in the original time weren’t so bad. Later they seemed to drift away. They got busy with each other and were spending all the time among themselves. They quit coming to meetings, and got more and more stingy. They learned a lot of little stuff, and forgot where they came from.
The Woman Who Married a Bear, p. 163
Human Origins: Are we hybrids?
On the Origins of New Forms of Life
Cat-rabbit Hybrids: Fact or fiction?
Georges Cuvier: A Biography
Prothero: A Rebuttal
Branches of Biology