Question of the monthDuring an interview with Martine Bérubé, research scientist at the Conservation genetics laboratory of the University of California in Berkeley, Whales online asked her the following question : Do rorqual whale hybrids exist?M. B.: Normally animals belonging to different species do not interbreed. However, some closely related species produce hybrids that are generally not fertile. This is the case of the mule which is the hybrid of the donkey and the horse, or the hybrid of the lion and the tiger. In the case of baleen whales, only the fin whale and the blue whale cross the species barrier and can give birth to hybrids. Contrary to the mule or the lion/tiger hybrid, one or the other of the parent species can be the mother or the father of these hybrids. Another difference; these hybrids may be fertile. Here are the facts. Five blue whale/fin whale hybrids have been discovered by scientists. Of the three that were female, two were sexually mature. The first could produce ova but appeared to be infertile, while the second was carrying a foetus. However, it is impossible to know if she would have carried this foetus to term or if the foetus would have survived after birth. In the case of the only male examined that had attained the age of sexual maturity, its sexual organs were not functional. Despite differences in size, colour and behaviour, it appears the fin whales and blue whales are species that remain genetically very close. Why are scientists interested in hybrids? Because hybridisation with a more widespread species could endanger the integrity of certain animal or plant species in decline. But, for now, blue whale/fin whale hybrids do not appear to be a problem for either parent species. |