Giraffes, the world’s tallest mammal, have long been assumed to be one species, but geneticists have now discovered there are actually four separate ones.
Because they do not appear to mate with each other — despite looking remarkably similar — two of newly defined species have suddenly become among the most endangered animals in the world.
They have been named the southern giraffe (Giraffa giraffa), the Masai giraffe (Giraffa tippelskirchi), the reticulated giraffe (Giraffa reticulata), and the northern giraffe (Giraffa camelopardalis).
Over the last 30 years, the total number of giraffes has fallen from more than 150,000 to less than 100,000.
Julian Fennessy, of Giraffe Conservation Foundation in Namibia, said: "With now four distinct species, the conservation status of each of these can be better defined.
“Northern giraffes number less than 4,750 individuals in the wild, and reticulated giraffes number less than 8,700 individuals.
“As distinct species, it makes them some of the most endangered large mammals in the world.”
The news of the four Giraffe species was revealed in the journal Current Biology with geneticists discovering there was at least as much differences in the DNA of the different types as there is between polar bears and brown bears, for example.
Professor Axel Janke, of Goethe University, who helped carry out the research, said: "We were extremely surprised, because the morphological [shape] and coat pattern differences between giraffe are limited.”
Previously it was assumed that giraffes all had the same ecological needs, but the fact there are four species instead of one means they each may have significantly different requirements.
“But no one really knows, because this megafauna has been largely overlooked by science,” Professor Janke said.
The tests were carried out after the Giraffe Conservation Foundation approached Professor Janke to find out whether past translocations of giraffe individuals had inadvertently mixed different species or subspecies as this could affect conservation efforts.
The researchers examined DNA from 190 giraffes from all nine previously recognised giraffe subspecies across Africa.
The term species refers to a group of animals who breed with each other but there can sometimes be cross-breeding with other animals.
For example, interbreeding between grizzly or brown bears and polar bears — as warming temperatures allow the two to increasingly interact — is producing an animal dubbed the grolar or pizzly.
It is thought this could one of the factors that will lead to the polar bears’ extinction as its DNA is gradually bred out.
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