A report in BMC Biology uses genetic evidence to show that there may be at least six species of giraffe in Africa.

Currently giraffes are considered to represent a single species classified into multiple subspecies.

The study shows geographic variation in hair coat colour is evident across the giraffe's range in sub-Saharan Africa, suggesting reproductive isolation.

"Using molecular techniques we found that giraffes can be classified into six groups that are reproductively isolated and not interbreeding," David Brown, the lead author of the study and a geneticist at the University of California Los Angeles (UCLA), told BBC News.