The bulk of reared animal hybridization work (on wild animals) is rather tame. Usually it's little more than placing related species in close proximity to one another, or skewing the sex ratios between them. A lot of this work isn't even designed to promote hybridization, it just *happens*. A lot of the tropical bird and freshwater aquarium trade works this way.drbill:If the two species don't want to mate in the wild, it seems to me there are RIM's (reproductive isolating mechanisms) already in place. The fact that they can mate in a forced situation says little if a behavioral or ecological RIM is in place that prevents them from doing so in the wild.
But since the animals are closely monitored in a closed environment, it is possible for us to track individual offspring to parents. Excepting charismatic megafauna, this ability is generally unavailable to biologists that work in the field. Since a lot of hybrid forms take more to one parent than another in appearance and behavior, the vast majority of them go unreported. That's one of the new prevailing theories, anyway.
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Robb, I have hunted all over the place for any reports of hybrid sharks. I have not only found NOTHING, there's virtually no theoretical discussion of it either. Of course, compared to many other fish lines, our knowledge of shark life history stinks for all but a few species. I don't think it's anything that is being seriously looked at. But don't feel too bad, inter-species breeding isn't looked at for the overwhelming majority of other animal species, either.