When I was a boy I got interested in the mammals of the world – including a particular affection for the Mustelidae, or weasel family. I guess that’s why it struck a chord when I found out about a large fossil mustelid described from Kenya as recently as 2003.
The focus of my boyhood interest was an encyclopaedia of mammals that I was writing: one A4 page per species, each with a pencil-crayoned drawing, range map, habitat and diet symbols, vital statistics, and a general write-up of whatever I could glean from the books I had available. I managed about sixty species before the project was overtaken by A-levels and dreams of going to Mars as a planetologist. But this particular hobby bequeathed me a robust knowledge of the taxonomy of mammals, the species being grouped into distinctive families whose names all end with ‘-idae’. The Mustelidae fascinated me because they are so anatomically diverse compared with other carnivore families, and because most of the British wild carnivores belong to this family: weasel, stoat, polecat, pine marten, mink, otter, badger.
In other parts of the world, they’re even more diverse and include some really spectacular animals, like the wolverine in the Arctic, the sea otter in the Pacific, the giant otter of the Amazon. In Africa, however, despite the high biodiversity of mammals in general, mustelids are thin on the ground, many of their usual niches being taken by mongooses and genets. The whole continent boasts only ten species: weasel, polecat, zorilla, Libyan striped weasel, white-naped weasel, ratel (or honey badger), and four kinds of otter. But if you go back into prehistory there are always more creatures to discover – and they always seem that bit more exotic because you know you’ll never be able to see them.
In particular, in the late Miocene epoch, around eight million years ago, there flourished in East Africa an animal named Ekorus, a powerfully built mustelid as big as a leopard, sixty centimetres tall at the shoulder, much bigger than any extant African mustelid. Unlike the low-slung build more typical of weasels, Ekorus was long-legged and had evolved into an active pursuit hunter that must have been competing against the big cats and hyenas.
I wasn’t able to engineer for Ekorus an instrumental role in Deep Time’s plot, but I loved the idea that so unusual and so little-known a giant weasel had once lived in Africa, so I gave the beast a cameo appearance in one of the novel’s descriptive interludes. My source of information about Ekorus and other prehistoric African mammals was Alan Turner and Mauricio Anton’s Evolving Eden.