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A unique animal
Giant otters, monk seals, walruses, spectacled bears, giant and red pandas and the odd-looking fossa are among the carnivores most in need of conserving.
That is according to the most-detailed study yet of the evolutionary history of carnivores and their relationships.
It examined 222 carnivore species including big cats, wolves, bears, seals, otters and their relatives.
It found that some species are so distinctive that special efforts should be made to ensure their survival.
Details of the research are published in the journal Molecular Phylogenetics and Evolution.
Despite the popularity of carnivores and the large number of studies done on them, scientists still do not completely understand how they evolved, and how modern species are related to one another.
"There are many questions that are yet to be answered in a satisfying manner," says Professor Ingi Agnarsson of the University of Puerto Rico in San Juan, who led the new study.
For example, the relationships between the cat-like families, known as feliforms, is unresolved.
"Even the relationships among the big cats, lion, tiger, leopard etc are really very poorly understood," he says.
Related to who?
The same is true for many dog-like species, such as racoon dogs, foxes,
and Asian wild dogs and
and scientists have struggled to understand how
are related to each other and other carnivores.
A particular problem has been finding out which animals are most closely related to red pandas.
In an attempt to resolve many of these issues, Prof Agnarsson and colleagues Laura May-Collado of the University of Puerto Rico and Dr Matjaz Kuntner of the Slovenian Academy of Science and Arts in Ljubljana, produced the first evolutionary tree for all carnivores.
They created it by studying 222 living carnivore species, and 17 subspecies, out of the 270 or so species of carnivore thought to exist.
That meant the researchers could check the relationships between 82% of all living carnivores, as compared to 28% studied in the previously most comprehensive review.
They also included four extinct species, such as the sabre-tooth cat and giant short-faced bear.
KEEP IT IN THE FAMILY
Generally, carnivores can be divided into two superfamilies: dog-like (Caniformia), and cat-like (Feliformia)
Dog-like carnivores are traditionally split into dogs and their relatives, and a group comprising bears, racoons, weasels, seals and the walrus
Cat-like carnivores are split into a range of groups, including cats, mongooses, hyenas and civets
The scientists studied how carnivores are related by comparing sequences of the cytochrome b gene, and checking how they varied between species.
"The gene we use is unusually reliable," says Prof Agnarsson.
They know that from other evolutionary studies that use the same gene, and because most of their own findings agree with previous research.
The new study supports the split of carnivores into two main evolutionary groups: dog-like carnivores called Caniforms and cat-like carnivores called Feliforms.
But it did throw up a few surprises (see Confused carnivores), which the researchers say will need further research to resolve.
As well as unpicking the relationships between carnivores, the study enabled the team to identify those species that are unusually distinct.
Among these unique carnivores are the monk seal,
Liberian mongoose, otter civet, Owston's palm civet, the fossa of Madagascar, which looks much like a dog that climbs trees (pictured above right), and the binturong of south-east Asia, which is also called the Asian bearcat.
"Some of the high-priority taxa for conservation have received very little attention and should be considered carefully in future conservation planning," says Prof Agnarsson.
The team's study supports ongoing efforts to conserve animals such as the monk seal and
The new study generally supports the traditional carnivores groups. However, it also finds that:
The kinkajou of South America is not related to racoons as thought
The red panda (above) may actually be most closely related to dogs and their relatives
South American jaguars are more closely related to Asian leopards and snow leopards than other big cats
But it suggests more needs to be done to safeguard of the futures of other carnivores such as the giant otter, fossa and walrus.
"Our analysis suggests we should pay careful attention to what is happening to
populations," says Prof Agnarsson.
"This species is extremely evolutionary distinct, as it contains a lot of evolutionary history not shared with any other species. So it is important in terms of biodiversity," he warns.
The species was recently listed as 'least concern' by the International Union for Conservation of Nature, suggesting it is not in imminent danger.
"But now we are not sure anymore that the species is 'safe'. Our results suggest we should fight to keep it safe," says Prof Agnarsson.
In a separate but related effort, the Zoological Society of London runs an EDGE (Evolutionary Distinct and Globally Endangered) of Existence programme that highlights the precarious conservation status of a range of animals beyond the carnivores.
On that list is 100 of the rarest animals including the
Chinese giant salamander,