A Nubian giraffe, part of the northern giraffe species
The most basic thing you thought you knew about giraffes is wrong — in fact, there are four species of giraffe, not one, scientists announced today: the southern giraffe, the Masai giraffe, the reticulated giraffe, and the northern giraffe. Genetically, they’re as distinct as brown bears are from polar bears. Today’s division has important implications for conservation because some of these newly discovered species are in grave danger, with just a few thousand individuals remaining in the wild.
The unexpected findings, described in a study published today in the journal Current Biology, show how little we know about one of the world’s most iconic animals. They’re also a vivid illustration of how much we still have left to do to ensure that giraffes won’t disappear because of poaching and habitat loss.
The reticulated giraffe
Giraffes are the tallest mammals on our planet. Until now, researchers had thought that all giraffes belonged to only one species, made up of up to nine subspecies that looked slightly different from each other.
A few previous studies, including one in 2007, showed that giraffe groups have some genetic differences, but those studies fell short of recognizing that these genetic differences are deep enough to account for separate species.
Today’s study was the first to conduct a thorough genetic analysis on all nine subspecies of giraffe, and the tests clearly showed that there are four genetically distinct species of the creature.
“We were very surprised ourselves. We didn’t expect to find species,” says Axel Janke, a professor at the Senckenberg Biodiversity and Climate Research Centre in Germany and one of the study's authors.
The northern giraffe
The research began five years ago, when Janke was approached by Julian Fennessy, the co-director and co-founder of the Giraffe Conservation Foundation in Namibia. Fennessy wanted to run some genetic tests to learn how similar giraffes in distinct parts of Africa are to each other.
The goal was to help Fennessy in a conservation effort where he relocates giraffes into parks or protected areas. So he wanted to know if he was mixing giraffes in ways he shouldn’t.
(If genetically different giraffes interbreed, that would eventually lead to a giraffe population that’s less diverse — and biodiversity is key for a healthy environment.)
So Fennessy helped Janke collect tissue from 190 giraffes. The samples were collected with darts that are shot at the giraffes from a distance; after the dart hits the animal, it captures a small piece of giraffe tissue and then drops to the ground. Janke and other researchers then analyzed the samples' DNA.
They looked at both the mitochondrial DNA, which is the DNA passed down from mothers to their offspring, as well as seven specific genetic markers — pieces of genetic material that can indicate if populations belong to different species.
The genetic differences led the researchers to declare four species, where before there had only been one.
The Masai giraffe
Giraffes come in four species – not one
Rather than up to 11 subspecies, giraffes can be grouped into four distinct species.
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.
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Researchers discover there are not one – but four species of giraffe
Researchers have discovered there are not just one but four distinct species of giraffe, overturning two centuries of accepted wisdom in a finding that could boost efforts to save the last dwindling populations.
Analysis of DNA evidence from all of the currently recognised nine sub-species found that there is not just one species of giraffe but enough genetic differences to recognise four distinct species. Experts said the differences are as large as those between brown bears and polar bears.
Giraffe have suffered a decline in number from around 150,000 across Africa three decades ago to 100,000 today, as their habitat has been turned over to agriculture. But as a single species the giraffe is currently listed as of least concern on the red list of endangered species, leaving the tallest living animals a relatively low conservation focus compared to rhino and elephant.
“People need to really figure out that giraffes are in danger. There are only 100,000 giraffes left in Africa. We’ll be working closely with governments and big NGOs to put giraffes on the radar,” said Dr Julian Fennessy, lead author of the new study which saw genetic testing in Germany on 190 giraffe.
The four recommended new species are the southern giraffe, with two subspecies, the Angolan giraffe and South African giraffe; the Masai giraffe; the reticulated giraffe; and the northern giraffe including the Kordofan giraffe and west African giraffe as subspecies.
If formally recognised as four separate species, three of those four would suddenly be deemed more seriously threatened by the red list, Fennessay said, which would hopefully catalyse greater efforts to protect them.
A Masai giraffe, one of the four newly recognised species, grazing inside Nairobi national park. Photograph: Simon Maina/AFP/Getty Images
While the southern giraffe was increasing markedly in number, populations in east and central Africa were in trouble, he said.
“It’s all habitat loss, fragmentation and a lot of that is, let’s be honest, linked to human population growth – increasing land for agricultural needs, whether for commercial or for subsistence farming,” he said, speaking from Windhoek, Namibia. “In some of these countries though there is illegal hunting or poaching causing the decline.”
Co-author Axel Janke, a geneticist at the Senckenberg Biodiversity and Climate Research Centre and Goethe University in Germany, said: “This has huge implications for conservation.
It’s also significant from an evolutionary aspect: the giraffe is a very young species and we see evolution, becoming species, in real time, happening in front of our eyes.
” Both said they were surprised at the number of genetically distinct species, because the currently recognised nine subspecies are relatively similar-looking. The most obvious differences are in the shape of their patterns and how far they extend, and how many horns the creatures have.
Tall tale: study reveals that giraffes are four distinct species, not one | CBC News
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 recognized 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,” Fennessy said.
Dramatic population decline
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, Fennessy said.
Giraffes stand up to about 5.5 metres 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.
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.
DNA reveals there are four giraffe species, not just one
Journal/conference: Current Biology
Organisation/s: Giraffe Conservation Foundation, Namibia
From: Cell Press
Genetic analysis uncovers four species of giraffe, not just one
Up until now, scientists had only recognized a single species of giraffe made up of several subspecies. But, according to the most inclusive genetic analysis of giraffe relationships to date, giraffes actually aren't one species, but four. For comparison, the genetic differences among giraffe species are at least as great as those between polar and brown bears.
The unexpected findings reported in Current Biology on September 8 highlight the urgent need for further study of the four genetically isolated species and for greater conservation efforts for the world's tallest mammal, the researchers say.
“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. Giraffes are also assumed to have similar ecological requirements across their range, he added, “but no one really knows, because this megafauna has been largely overlooked by science.”
Giraffes are in dramatic decline across their range in Africa. Their numbers have dropped substantially over the last three decades, from more than 150,000 individuals to fewer than 100,000. Despite that, the researchers say that there has been relatively little research done on giraffes in comparison to other large animals, such as elephants, rhinoceroses, gorillas, and lions.
About five years ago, Julian Fennessy of Giraffe Conservation Foundation in Namibia approached Janke to ask for help with genetic testing of the giraffe.
Fennessy wanted to know how similar (or not) giraffes living in different parts of Africa were to each other, whether past translocations of giraffe individuals had inadvertently “mixed” different species or subspecies, and, if so, what should be done in future translocations of giraffes into parks or other protected areas.
In the new study, Janke and his research group examined the DNA evidence taken from skin biopsies of 190 giraffes collected by Fennessy and team all across Africa, including regions of civil unrest. The extensive sampling includes populations from all nine previously recognized giraffe subspecies.
The genetic analysis shows that there are four highly distinct groups of giraffe, which apparently do not mate with each other in the wild. As a result, they say, giraffes should be recognized as four distinct species. Those four species include (1) southern giraffe (Giraffa giraffa), (2) Masai giraffe (G.
tippelskirchi), (3) reticulated giraffe (G. reticulata), and (4) northern giraffe (G. camelopardalis), which includes the Nubian giraffe (G. c. camelopardalis) as a distinct subspecies.
The elusive Nubian giraffe from Ethiopia and the South Sudan region was the first described some 300 years ago, Fennessy says, and is now shown to be part of the northern giraffe.
The discovery has significant conservation implications, the researchers say, noting that the International Union for Conservation of Nature and Natural Resources (IUCN) Species Survival Commission Giraffe and Okapi Specialist Group recently submitted an updated proposed assessment of the giraffe on the IUCN Red List taking into consideration their rapid decline over the last 30 years.
“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.
“Working collaboratively with African governments, the continued support of the Giraffe Conservation Foundation and partners can highlight the importance of each of these dwindling species, and hopefully kick start targeted conservation efforts and internal donor support for their increased protection.
“As an example,” he adds, “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.”
Janke and Fennessy say that they are now analyzing the amount of gene flow between the giraffe species in greater detail. In addition to expanding the ecological and species distribution data, they want to better understand the factors that limit gene flow and the giraffes' differentiation into four species and several subspecies.
DNA Reveals Giraffes Are 4 Species–Not 1
One of the most iconic animals in Africa has a secret. A genetic analysis suggests that the giraffe is not one species, but 4 separate ones—a finding that could alter how conservationists protect these animals.
Researchers previously split giraffes into several subspecies on the basis of their coat patterns and where they lived.
Closer inspection of their genes, however, reveals that giraffes should actually be divided into four distinct lineages that don’t interbreed in the wild, researchers report on 8 September in Current Biology.
Previous genetic studies have suggested that there were discrete giraffe populations that rarely intermingled, but this is the first to detect species-level differences, says Axel Janke, a geneticist at Goethe University in Frankfurt, Germany, and the study’s senior author.
“It was an amazing finding,” he says. He notes that giraffes are highly mobile, wide-ranging animals that would have many chances to interbreed in the wild if they were so inclined: “The million-dollar question is what kept them apart in the past.” Janke speculates that rivers or other physical barriers kept populations separate long enough for new species to arise.
Ruminating on ruminants
The study tracked the distribution of 7 specific genetic sequences—chosen to enable researchers to measure genetic diversity— in nuclear DNA from skin biopsies of 190 giraffes. They also looked at the animals’ mitochondrial DNA.
The sequences fell into four distinct patterns that strongly suggested separate species. Janke says that each of the four species is about as different from each other as the brown bear (Ursus arctos)is from the polar bear (Ursus maritimus).
The researchers suggest replacing the current species name, Giraffa camelopardalis,with four new ones: the southern giraffe (G. giraffa), found mainly in South Africa, Namibia and Botswana; the Masai giraffe (G. tippelskirchi) of Tanzania, Kenya and Zambia; the reticulated giraffe (G.
reticulata) found mainly in Kenya, Somalia and southern Ethiopia; and the northern giraffe (G. camelopardalis), found in scattered groups in the central and eastern parts of the continent. The one remaining subspecies is the Nubian giraffe (G. camelopardalis camelopardalis) of Ethiopia and South Sudan.
It is a distinct subspecies of the northern giraffe.
“This study is pretty persuasive,” says George Amato, a conservation biologist at the American Museum of Natural History in New York City, who has conducted extensive research on the genetics of African wildlife. “I applaud the science and what it adds to our understanding of African biogeography.”
Janke says that the findings have obvious implications for conservation: all of the giraffe species must be protected, with special attention paid to the northern and reticulated giraffe.
Each of those species has fewer than 10,000 individuals.
According to the Giraffe Conservation Foundation, the overall number of giraffes has dropped from more than 140,000 in the late 1990s to fewer than 80,000 today, largely because of habitat loss and hunting.
But applying the new findings to conservation efforts may be difficult. “So far, we haven’t really been able to fully appreciate the power of genomics in conservation,” says Aaron Shafer, a geneticist at Trent University in Peterborough, Canada. Genetics can uncover new species, but it's not always obvious how that knowledge should guide decisions about animal protection.
Amato notes strong parallels between giraffes and African elephants, which were classified as a single species until a 2010 study provided genetic evidence that there were actually two: forest elephants (Loxodonta cyclotis)and savannah elephants (Loxodonta africana). That finding increased calls for extra protection of the forest elephant, the rarer of the two.
However, assessments of African elephants by the International Union for Conservation of Nature treat the animals as one species, due to concerns that splitting them into two species would place forest and savannah elephant hybrids into a kind of conservation limbo.
Evidence showing that many populations of American bison (Bison bison) carry small amounts of domestic-cattle DNA prompted concerns over whether it was worth saving the contaminated herds, since they weren't completely wild. Amato and other biologists have argued that the animals still deserve protection. “They are ecologically functional bison,” Amato says.
It remains to be seen whether the latest study will have any impact on giraffe conservation, he says. The most immediate effects may be felt in zoos that trade the mammals for breeding purposes: now that researchers have identified separate species, it should be easier for zookeepers to make appropriate matches.
The discovery of separate giraffe species could have come sooner, but the animals have been largely neglected by science. “Giraffes were fairly ubiquitous in their habitat, and they weren’t much of a target for poachers,” Amato says. “They are an iconic animal, but they were taken for granted.”
This article is reproduced with permission and was first published on September 8, 2016.