Giraffes come in four species – not one
First detailed genetic study of the iconic African animal shows they need more conservation support. Amy Middleton reports.
Giraffes are divided into four distinct species, not one species with many offshoots, according to a detailed genetic study.
Until now, it’s been assumed that giraffes comprise one species with between nine and 11 subspecies. But researchers led by Julian Fennessy at the Giraffe Conservation Foundation in Namibia claim there is enough genetic distinction to warrant four separate species, each with their own particular needs.
The work was published in the journal Cell Biology.
Even though giraffe populations have dropped below 100,000 individuals in the wild, there’s been far less research done into the world’s tallest living mammal than other endangered species such as elephants, gorillas and rhinos.
“Even after a century of research, the distinctness of each giraffe subspecies remains unclear, and the genetic variation across their distribution range has been incompletely explored,” the paper explains.
Given this new discovery, the team recommends a more considered approach to conservation efforts around giraffes, claiming that some species are as genetically distinct as polar bears and brown bears.
“We were extremely surprised, because the morphological and coat pattern differences between giraffe are limited,” says Axel Janke, a geneticist at the Senckenberg Biodiversity and Climate Research Centre and Goethe University in Germany, and co-author of the paper.
The claim that all giraffes have similar environmental needs must also be challenged, says Janke: “No one really knows, because this megafauna has been largely overlooked by science.”
The researchers aimed to study the genetics of giraffe populations across Africa, particularly focusing on how relocations and inter-population breeding had affected the species.
Fennessy and Janke and their crew examined mitochondrial DNA from skin samples of 190 giraffes from across Africa – the first genetic study to represent all nine known subspecies.
The findings named four distinct species of giraffe: the southern giraffe (Giraffa giraffa), Masai giraffe (G. tippelskirchi), reticulated giraffe (G. reticulata) and northern giraffe (G. camelopardalis). These four species do not interbreed in the wild.
Some existing subspecies have been reclassified. The Thornicroft’s giraffe and Masai giraffe, for instance, were found to be genetically identical, and are now grouped together under one species name.
The separation of species will affect each giraffe’s respective endangered status, as stated by the International Union for Conservation of Nature and Natural Resources (IUCN).
“With now four distinct species, the conservation status of each of these can be better defined and in turn added to the IUCN Red List,” Fennessy says.
Fennessy refers to the heightened rarity of two of the species, the reticulated and northern giraffes, the latter of which includes the elusive Nubian giraffe as a subspecies.
“Northern giraffe number less than 4,750 individuals in the wild, and reticulated giraffe number less than 8,700 individuals.
“As distinct species, it makes them some of the most endangered large mammals in the world.”
The team says more research is needed to fully understand the distinctions between the four species and are already planning further genetic analysis to observe gene flow in more detail.