This revelation came about via the large-scale testing of hundreds of giraffe skin biopsy samples from each and every one of the previously recognized giraffe subspecies, collected over the course of a decade through remote and dangerous regions of the continent by the Giraffe Conservation Foundation (GCF). For the first time, this included a sample from the Nubian giraffe, an elusive and endangered subspecies found in Ethiopia and volatile Sudan and South Sudan.
The genetic analysis, conducted by a team at the Senckenberg Biodiversity and Climate Research Center, took the researchers by surprise. Not only does the evolutionary history of the giraffe appear to be more complex than previously thought, but some subspecies, including Rothschild’s giraffe and Thornicroft’s giraffe, have completely disappeared – they happen to be genetically indistinct from the Nubian and Masai giraffes, respectively.
The genetic diversity reveals that all four new species had a common ancestor between 0.4 and 2 million years ago. Although four new species of giraffes arising from a prehistoric relative as little as 400,000 years ago sounds surprising, this is actually in line with what is expected for species diversification in mammals.
As wonderful as it is to think that there have been all these distinct species of giraffes wandering unnoticed before our very eyes for millennia, this study will also seriously boost conservation efforts for the giraffe, which is increasingly threatened by human activity. The most up-to-date estimate of their numbers suggests 40 percent of their population has disappeared in the last 15 years, and as ever, nefarious human activity is to blame.
Thanks to this study, instead of grouping all giraffes as one, more precise estimates about their biodiversity levels can be made using this genetic toolkit. “Now that we know that there are four giraffe species, it is even more important and urgent to support governments and other partners across Africa to protect giraffe,” lead author Dr Julian Fennessy, co-director of the GCF, noted.
A baby giraffe in its natural habitat. aaltair/Shutterstock