>>13408541>>13408545>>13408550Wolves and coyotes, dogs and jackals, domestic (african) cat and european wildcats, cuban crocodiles and american crocodiles, greylag geese and swan geese, pic related, western and glaucous-winged gulls, bottlenose dolphins and false killer whales (intergeneric fertile hybrid!), spinner and striped dolphins, bornean and sumatran orangutan, homo sapiens and neanderthals (also that ghost species in op)....
The Mallard duck can crossbreed with 63 (sixty-three!) other duck species, to the point of endangering some of those species survival. They call this genetic pollution...