The jaguar is a close relative of the Asiatic leopard and must have had a common ancestor within the last 5 million years. The South American tapir is obviously closely related to the Malayan tapir and must also have had a common ancestor within he last 5 million years. How did the leopard and tapir, typically tropical species, get from Asia to South America?
An obvious route would be the land route via the Bering Straits and the southern shore of Alaska which was used by humans about 15,000 years ago when the Ice Age had lowered sea level, but both animals are tropical and it is hard to believe they would have chosen such an icy route. The jaguar and tapir have in any case been separated from their Asiatic relatives for a lot longer than 15,000 years. I am wondering whether they could have arrived via a different route from the one chosen by the earliest human inhabitants of the Americas. Can anyone throw any light on this?
Continental drift played a part in isolating Old World monkeys from South American monkeys and setting Australia adrift carrying only marsupials, so is there a possibility that when Africa and Amazonia were closer together, immigration from Africa could have taken place, bearing in mind that there were times when sea levels were much lower?