Giraffe species increase four-fold
It has long been thought that there's only one species of giraffe. However, a recent study of the animal's genes has concluded that there are in fact four different species. The discovery was made by Axel Janke and his team, at the Senckenberg Society, Goethe University, who worked with the Giraffe Conservation Foundation to study giraffe from across Africa. Laura Brooks caught up with Axel to find out more...
Axel - There's very little research on giraffes - we are among the first to make genetic studies. Yes they have simply been overlooked by science describing them originally as one species and everybody was happy with that and stuck to it. And we, for the first time, looked more closely at that and found these four different species.
Laura - I see. You'd think that with them being the tallest mammal that they would be the ones doing the overlooking but, in fact, we've overlooked them it seems?
Axel - Yes, absolutely right. It is surprising that so little research has been done on the giraffe, which is an iconic species for Africa.
Laura - Yeah. What does a species mean to you? So when I was at school I was told that a species was a group of animals that can interbreed but I've since learned that, actually, the definition of "species" is a bit more subtle than that. So what does species mean to you in your research?
Axel - The definition is very similar to what you have learnt. It's a group of animals that can interbreed in nature and, obviously, these four species of giraffe don't do it. We don't know the reason why but we don't see the geneflow between these species - these four species are genetically distinct so something prevents them from interbreeding in nature. They can interbreed in captivity in zoos, and they do so, and they have viable and fertile offspring but again, in nature, for some reason they don't do it.
Laura - And you say that their genes are distinctly different - how different are they?
Axel - They're different enough to call them species, but if you want to have a comparison, they're as different as, for example, genes between a polar bear and brown bear.
Laura - Wow! That's quite surprising isn't it because they look very similar - isn't that right?
Axel - That's right. They are not as distinct as a polar and brown bear where we immediately see we have different species here. But if you look closely you see very distinct differences between the coat pattern. The reticulated giraffe has very straight lines around the brown fur region, whilst the masai giraffe the lines of these brown spots is very jagged and the spots are much darker, and so there are more differences also between these different species if you know where to look.
Laura - And what do we know about how these different species came about - is it simply that the different groups were geographically isolated from each other?
Axel - that's an excellent question. We don't know and this is an exciting and fascinating part of this story which we study now. We find them to be distinct but we have no idea how they became distinct - it can be behaviour, it can be geographical separations. There can be other things - we don't know.
Laura - Now giraffes are endangered animals, aren't they? In terms of conservation, what are the implications of this discovery?
Axel - The implications are huge because the giraffe has been seen as a single species - now we have four species. And some of these species only have numbers of five or eight thousand individuals and so they need to be protected. Now the Giraffe Conservation Foundation has the science to address African governments to address conservation organisation to convince them that the giraffe needs to be protected.
Laura - So presumably they'll be looking at targeting conservation efforts at these four, as we now understand, distinct species?
Axel - Yes, that's right.