An issue that has been on my mind for a good many years is whether integrity of species and subspecies is in any way important for maintaining captive populations. Is it a measure of their validity? It would be worthwhile to explore the forumsters’ views on hybrids and crossbreeds in captive populations of endangered species. Is it detrimental to maintain the integrity of valid (sub-)species? Alternatively, do you feel there are cost / benefits involved in the practice? Is it acceptable, necessary, unavoidable et cetera et cetera. Examples where this applies are sometimes entire captive populations or part of individuals comprising a captive stock maintained by some or quite of few zoos. Quite a number of megavertebrates come to mind like elephant, giraffe, a good number of the Carnivora (except perhaps the majority of tigers and leopards in established conservation breeding programmes), wisent/bison (it has been discussed elsewhere fleetingly). Not to name assorted bird, reptile, amphibian and other taxa / fyla. Opinions most welcome!