Last summer, I took my son to Big Bone Lick a state park in northern Kentucky. It’s famous for, amongst other things, having been a historic salt lick, having sulfur springs, and having marshes that trapped and preserved ancient megafauna. I bring it up because my son – in that way five-year-olds will – decided to bring it up last night. And one of the things he brought up were the buffalo. Because he loves buffalo, along with any other big animals.
This reminiscing brought up several questions. One of them was “have buffaloes been around a million years?” He’s familiar with evolution in a five-year-old way, thanks to an interest in dinosaurs and an amazing book titled Grandmother Fish, so he knows that not all the animals he sees today were around a long time ago. So, lets try to answer the question.
First off, there is no such animal as an American buffalo. The animal we incorrectly call a buffalo is the American bison (Bison bison) – part of class Mammalia (meaning it’s an endothermic animal with a neocortex and mammary glands), superorder Ungulata (so it has hooves), and family Bovidae (meaning the hoof is cloven and it’s a ruminant). But that’s being a little pedantic, because I know what animal my son is referring to. So, has the American Bison been around for a million years?
according to Bison Belong In Banff National Park, bison have been present in North America for approximately 300,000 years. Modern bison are specifically “descended from populations living south of ice sheet before the Last Glacial Maximum (Wisconsin Glaciation approx. 20,000 years ago). The modern forms of plains bison (B.b. bison) and the wood bison (B.b. athabascae) are the most recent evolution variant, about 5,000 years ago, one happening in the North (wood bison) and one in the South (plains bison).” So, clearly and unsurprisingly, the American bison has not been around a million years.
But bison, in some form, have.
The Oxford Journal Molecular Biology and Evolution ran an article titled Maternal and Paternal Lineages in Cross-Breeding Bovine Species. Has Wisent a Hybrid Origin? back in 2003. The article reports that water buffalo (Bubalus bubalis) and African buffalo (Syncerus caffer) separated from the Bos and Bison species between 5 and 10 million years ago (MYA). Bos and Bison then split into four distinct lines:
They don’t really provide a specific time-frame for when these divergences happened, but they do note that “after diverging for 1 Myr [million years] or less, the speciation within the Bovini is not yet complete and female hybrid offspring from Bos and Bison species are fertile.” Howevere, they also note the following:
These data indicate that during the Late Pliocene–Early Pleistocene the ancestral bison originated in Southern Asia from the ancestral Leptobos and spread over the temperate zone. In the Early Pleistocene, immigrants in North America were the ancestors of the Bison antiquus, from which the extant Bison bison descended.
The Pliocene ended roughly 2.58 MYA, followed by the Pleistocene. That gives us a figure of around 2.58 MYA for the Leptobos. So, were there bison a million years ago? Yes. But they weren’t Bison bison.