Image copyright Reuters

It is a famous, gentle giant of the African savannah, but the giraffe's genetics have just revealed that there is not one species, but four.

Giraffes have previously been recognised to be a single species divided into several sub-species.

But this latest study of their DNA suggests that four groups of giraffes have not cross-bred and exchanged genetic material for millions of years.

This is a clear indication that they have evolved into distinct species.

The study published in the journal Current Biology has rewritten the biology of Earth's tallest mammal.

The scientists say their findings could inform the conservation efforts for all four species of giraffe.

Conservation was the catalyst for this genetic research; the Giraffe Conservation Foundation asked the team to carry out genetic analysis of giraffes in Namibia.

The foundation wanted to understand the genetic differences between different giraffe populations, to see how the animals might be affected if different subspecies were mixed together when animals were moved into protected areas.

What we found then, says Axel Janke, a geneticist at the Senckenberg Biodiversity and Climate Research Centre, who led the research, "was that the sub-species were genetically very different and separate.

"I'd never seen that in a population study [of a species] before."

This initial study examined what is known as mitochondrial DNA - a packet of DNA within every cell's "engine". This is useful for population genetics - it can be easily isolated and contains lots of known variants that can track relatedness.

But mitochondrial DNA is not part of the code that builds an animal, so Dr Janke decided to examine and compare parts of that code - the nuclear DNA.

"It turned out, he told BBC News, that, for example, "the whole clade of northern giraffes was very different from reticulated giraffes."

"Our findings indicated four distinct species."

Those four species include:

southern giraffe ( Giraffa giraffa ),

), Masai giraffe ( G. tippelskirchi ),

), reticulated giraffe ( G. reticulata )

) northern giraffe (G. camelopardalis), which includes the Nubian giraffe (G. c. camelopardalis) as a distinct but related subspecies.

While giraffes had always been thought to be of one species, Dr Janke likened the difference between one species and another - in terms of their genetic code - to that of a Polar bear compared with a brown bear.

Image copyright Julian Fennessy Image caption Juvenile Southern Giraffes

Image copyright Julian Fennessy Image caption Reticulated giraffe

This suggests that each species is adapted for a specific environment or diet - a question that is the subject of his team's next research project.

Neglected by science

Matthew Cobb, professor of zoology at the University of Manchester explained that the "four groups of giraffes had "been separated for 1-2 million years, with no evidence of genes being exchanged between them".

Image copyright Julie Maher Image caption Masai Giraffe

Image copyright Julian Fennessy (GCF) Image caption Northern Giraffe

"This is an important finding that will enable conservation biologists to target their efforts and, perhaps, to come up with new conservation approaches in captivity or in the wild, based on the genetic similarities and differences between these groups," Professor Cobb told BBC News.

Media playback is unsupported on your device Media caption Mike Jordan from Chester Zoo tells the BBC's Victoria Gill how a surprising discovery about giraffes could impact conservation.

Dr Janke commented: "We've clearly completely forgotten what a giraffe is."

He added that conservation programmes focused on specific species - understanding an animal's life, behaviour and habitat, to inform how it can be protected in the wild.

In the last 15 years, the population of giraffes has declined by 40% - there are now an estimated 90,000 individuals in the wild. But, as a single species, they are classified by the International Union for the Conservation of Nature as of Least Concern.

Now, it is clear that each of these four newly classified species could be faring very differently.

It's important to raise awareness for conservation, said Dr Janke, "to protect his beautiful animal of which we know so little."

Follow Victoria on Twitter.</s>After studying DNA evidence, scientists have discovered that the giraffe is not one species, but four.

They have said the four distinct species are genetically at least as different as brown and polar bears.

Until now, only a single species of giraffe made up of several sub-species had been recognised.

The unexpected discovery, published in the journal Current Biology, highlights the urgent need to protect the world's tallest mammal, researchers have said.

Geneticist Professor Axel Janke, from Goethe University in Germany, said: "We were extremely surprised, because the morphological and coat pattern differences between giraffe are limited."

Prof Janke and his team looked at DNA taken from skin samples from 190 giraffes from across Africa.

Analysis showed there were four highly distinct groups of giraffe, which apparently do not mate with each other in the wild.

The scientists categorised four species of the animal: the southern giraffe (Giraffa giraffa), the Masai giraffe (Giraffa tippelskirchi), the reticulated giraffe (Giraffa reticulata), and the northern giraffe (Giraffa camelopardalis).

Giraffes are in dramatic decline across their range in Africa. with numbers have dropping from more than 150,000 individuals to fewer than 100,000 in the past three decades.

Yet relatively little research has been done on giraffes, compared with other large animals such as elephants, rhinoceroses, gorillas and lions, say the researchers.

The northern giraffe includes the elusive sub-species, the Nubian giraffe, which lives in Ethiopia and South Sudan.</s>There are four species of giraffe, not one: scientists

There are actually four species of giraffe, not one as previously believed, researchers said Thursday in a discovery that could change conservation efforts for the world's tallest mammal.

The study in the journal Current Biology is based on DNA evidence from skin biopsies of 190 giraffes across Africa.

Giraffe populations have dropped dramatically in Africa over the past few decades, going from about 150,000 to less than 100,000.

But giraffes have been little studied, compared to other large animals like elephants, rhinoceroses, gorillas and lions.

Until now, researchers believed there was one species of giraffe, and as many as nine subspecies.

The latest data shows there are four distinct species of giraffe which apparently do not mate with each other in the wild.

"Those four species include (the) southern giraffe (Giraffa giraffa), Masai giraffe (G. tippelskirchi), reticulated giraffe (G. reticulata), and northern giraffe (G. camelopardalis), which includes the Nubian giraffe (G. c. camelopardalis) as a distinct subspecies," said the study.

It also said the genetic differences among giraffe species "are at least as great as those between polar 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.

"Consequently, giraffes should be recognized as four distinct species despite their similar appearance."

Now, researchers say some giraffes could be considered for listing as a vulnerable or endangered species on the Red List maintained by the International Union for Conservation of Nature (IUCN).

For example, the northern giraffe numbers less than 4,750 individuals in the wild. There are fewer than 8,700 reticulated giraffes, making each species among the most endangered large mammals in the world, the research team said.</s>Low population levels of two of them — the northern giraffe and reticulated giraffe — make them some of the world's most endangered large mammals.

Genetic research on the world’s tallest land animal has found that there are four distinct species of giraffe, not just one as long believed, with two of them at alarmingly low population levels.

Scientists on Thursday unveiled a comprehensive genetic analysis of giraffes using DNA from 190 of the towering herbivores from across their range in Africa.

The genetic data showed that four separate species of giraffes that do not interbreed in the wild inhabit various parts of the continent.

“We were extremely surprised,” said conservationist Julian Fennessy, co-director of the Namibia-based Giraffe Conservation Foundation.

Beyond genetics, the researchers identified differences among the four species including body shape, coloration and coat patterns.

Genetic differences among the four species were comparable to those between polar bears and brown bears, said geneticist Axel Janke of the Senckenberg Biodiversity and Climate Research Centre and Goethe University in Germany.

Until now, scientists had recognised a single species, with the scientific name Giraffa camelopardalis.

The study identified the four separate species as: the southern giraffe (Giraffa giraffa), with a population of 52,000; the Masai giraffe (Giraffa tippelskirchi), with 32,500; the reticulated giraffe (Giraffa reticulata), with 8,700; and the northern giraffe (Giraffa camelopardalis), with 4,750.

“The conservation implications are immense and our findings will hopefully help put giraffe conservation on the map," Mr. Fennessy said.

The giraffe currently is not listed as endangered, although its population has declined dramatically over the past three decades from more than 150,000 to fewer than 100,000, the researchers said.

But the low population levels of the northern giraffe and reticulated giraffe make them some of the world's most endangered large mammals and of high conservation importance, Mr. Fennessy said.

Giraffes stand up to about 18 feet (5.5m) tall, with long necks and legs, a sloped back and two to five short knobs called ossicones atop the head. They have a tan, white or yellowish coat blotched with brownish patches.

They roam the savannas of central, eastern and southern Africa, as far north as Chad, south to South Africa, east to Somalia and west to Niger.

Mr. Fennessy said the biggest threats to the giraffe include habitat destruction due to human population growth as well as poaching for bush meat, their tail hair and “medicinal” parts.

Their closest relative is the long-necked African mammal called the okapi.

The research was published in the journal Current Biology.
Genetic tests show that the genus giraffa, previously thought to contain one extant species, actually consists of four.