Jan 25

A polar bear has been recorded swimming continuously for over nine days, a feat of endurance which could reveal the potential impacts of climate change.

Photo of polar bear swimming

Polar bears have large, strong limbs and huge forepaws which are used like paddles when swimming.

The price of a long swim

The long-distance swim, covering an incredible 687 kilometres (426 miles), was undertaken by a female polar bear fitted with a GPS collar which allowed scientists to track the bear’s movements.

Photo of polar bear cub peering over adult female

A polar bear cub remains dependent on its mother for around two and a half years, but may be unable to endure the high costs of a long swim.

Although polar bears are often known to swim between land and sea ice to hunt seals, this long journey came at a high cost to the female bear. In the two months over which she was followed, the female lost 22 percent of her body fat, and also lost her yearling cub, for which the long swim would have been even more energetically costly.

Climate change a threat to polar bears

The results of this study, published in the journal Polar Biology, demonstrate the remarkable swimming abilities of polar bears, but also the potential risks of a changing climate. Scientists fear that increased melting of sea ice as a result of global warming may force polar bears to undertake more frequent, longer journeys through freezing waters, at a potential cost to their health and the survival of their cubs.

Photo of polar bear leading cub across melting ice

The main threat to the polar bear is believed to be melting of Arctic sea ice as a result of climate change. This species is listed as Vulnerable by the IUCN.

According to George Durner, one of the scientists who undertook the study, “We are in awe that an animal that spends most of its time on the surface of sea ice could swim constantly for so long in water so cold. It is truly an amazing feat.” However, he adds that their dependency on sea ice “potentially makes polar bears one of the most at-risk large mammals to climate change.

Read the full story in the BBC’s article.

Watch underwater footage of a polar bear swimming on ARKive.

Liz Shaw, ARKive Species Text Author

Jan 25

Lonesome George, the last Abingdon Island tortoise (Geochelone abingdoni) in the world, has been tasked with preserving the genetic legacy of his species by reproducing.  

At the grand old age of 90, George is in his sexual prime so conservationists from the Galapagos National Park have identified two new female partners from a closely related species, the Hood Island tortoise (Geochelone hoodensis) to try to encourage him to mate.

Photo of a Volcan Alcedo tortoise walking amongst sulpur fumaroles (geysers)

Eleven species of giant tortoise are currently recognised, each occupying isolated islands within the Galapagos chain. The species can be generally separated into those with 'domed' shells, which occur on larger, wetter islands, and smaller tortoises with 'saddleback' shells that are found on smaller islands with dry vegetation.

Islands’ most eligible bachelor 

Ecuador’s Galapagos Islands are home to many unusual species, but none are as rare as Lonesome George. Despite being the Galapagos Islands’ most eligible bachelor, for the last 20 years George has tried and failed to sire offspring with his previous mates, as none of their eggs resulted in viable offspring. 

But George still has plenty of life left in him, and scientists now believe George may have a better chance of reproducing with his two new partners from the archipelago’s Spanish Island. Genetic studies have shown that the newly arrived tortoises “are genetically closer… more compatible, and could offer greater possibilities of producing offspring”, the park’s statement said.

Photo of a group of Volcan Alcedo tortoises in shallow pool

These tortoises spend a large part of the day grazing in small groups. During the rainy season a lot of time is spent wallowing in shallow pools, and at night tortoises can be found in depressions dug into the ground.

World’s ‘rarest living creature’ 

If this attempt fails, Diego Cisneros, a herpetologist at the National Park, says there could be other options. “There are certain methodologies, hybridization, cloning, etc. but they are not so easy and we’re talking about reptiles, the study of which is not as advanced as the studies of other animals.” 

It would be an encouraging story for all threatened species if George, the world’s ‘rarest living creature’, was to pass on his legacy to another generation. So let’s hope it’s love at first sight and George and his two new companions hit if off. 

Watch a video of Lonesome George on ARKive. 

Alex Royan, ARKive Species Text Author

Jan 24

A distinct population of orcas in the north-east Pacific has been found to hunt sharks, a tough diet which wears down their teeth.

Photo of captive orca mouth detail

A captive orca showing its teeth. Also known as the killer whale, the orca is a widespread, intelligent and versatile predator.

As a species the orca has a very varied diet, but different orca populations are known to specialise in hunting different types of prey. For example, in the north-east Pacific, ‘resident’ orcas feed on fish, particularly salmon, while ‘transients’ specialise in marine mammals such as sea lions, other cetaceans and even large whales.

Photo of orca attempting to drown grey whale calf

Some orcas specialise in hunting marine mammals, including large species such as the grey whale.

Now a third type, the ‘offshore’ orca, has been shown to hunt sharks, providing the first evidence of the preferred prey of this population. The study, published in the journal Aquatic Biology, also found that the teeth of offshore orcas were typically worn right down to the gums – damage which was most likely caused by the tough, abrasive nature of shark skin.

Photo of orca beaching to attack sea lion

Orcas vary widely in their hunting techniques. Some orcas in Argentina have learnt to intentionally strand themselves to reach seals and sea lions on the shore.

Although further research is needed to determine whether these shark-eating orcas are as specialised as other orca groups, the findings of this study add weight to growing calls for different types of orca to be recognised as distinct species.

Photo of orca pod blowing air at the surface

Orcas are highly social, living in complex groups which often share a distinct vocal repertoire. Resident, transient and offshore orcas are not known to interbreed.

Not only do different types of orca specialise in different prey, but the distinct groups also vary in appearance and behaviour, and do not interact with each other. Recent studies have also highlighted genetic differences between them.

If the different types of orca are indeed found to represent separate species, it will have important implications for the conservation of these charismatic predators.

View a slideshow of 52 stunning orca photos on ARKive.

Liz Shaw, ARKive Species Text Author

Jan 24

The ‘newest’ cat species to science, Diard’s clouded leopard (Neofelis diardi), actually exists in two distinct forms, a new study has confirmed.

This enigmatic big cat was only described as a species in 2007, previously being considered as a subspecies of its mainland relative, the clouded leopard. Now a genetic analysis has discovered that Diard’s clouded leopard comes in two forms, one living in Sumatra (Neofelis diardi diardi), the other on Borneo (Neofelis diardi borneensis).

Photo of Diard's clouded leopard walking in natural forest habitat

A Diard's clouded leopard caught with a camera trap while walking in natural forest habitat.

The first footage of Diard’s clouded leopard in the wild was captured only last year, when a team of researchers from the Leibniz Institute for Zoo and Wildlife Research in Berlin, Germany, captured images of a Diard’s clouded leopard walking along a road. Now these researchers have published new research which reveals even more about this mysterious cat.

Clouded leopard photo

Clouded leopards are the most elusive of all big cats. Living across south-east Asia, into China and India, clouded leopards have larger cloud-like spots than ordinary leopards.

Published in the journal Molecular Phylogenetics and Evolution, the study conducted molecular and genetic studies on 15 Diard’s clouded leopards living in Borneo and 16 living in Sumatra. In addition, 28 skulls from a further 28 Diard’s clouded leopards and the fur coats of 20 specimens held in museums were examined, as well as the coats of cats photographed on both islands. 

The differences between the two forms are not obvious. But as well as being genetically distinct, the Diard’s clouded leopards on Borneo and Sumatra are morphologically different, having unique features in their skulls and teeth.

Close up photo of a Diard's clouded leopard

Diard’s clouded leopard has impressive tree climbing abilities, and is capable of running head-first down tree trunks, climbing about on the underside of branches, and hanging upside down by its hind feet with the tail providing balance.

It is unclear what caused Diard’s clouded leopard to evolve into two forms. 

“So far we can only speculate about the specific course of events in the evolution of the clouded leopard,” said Joerns Fickel, a team member at the Leibniz Institute for Zoo and Wildlife Research. 

But researchers think that a volcanic eruption on Sumatra 75,000 years ago may have wiped out most clouded leopards. One group survived in China and colonised the rest of mainland Asia, whilst another group hung on in Borneo to later become Diard’s clouded leopard. This species may then have evolved into two types after a group colonised Sumatra via glacial land bridges, and then became cut off as sea levels rose.

Watch a video of the clouded leopard on ARKive.

To read more about this, see the BBC article.

Alex Royan, ARKive Species Text Author

Jan 21

Wild bird populations in the UK appear to be falling dramatically, according to new government figures released yesterday.

By comparing UK wild bird populations from the 1970s to wild populations in 2009, the British Trust for Ornithology (BTO) has revealed some worrying trends.

Grey partridge photo

The rate of decline in farmland birds such as the grey partridge has increased over recent years.

Some of the worst hit farmland birds, such as the grey partridge, turtle dove, starling, tree sparrow, corn bunting and yellow wagtail, have all declined by around 70% since the 1970s.  

Woodland birds have also been hard hit, with species such as the blackbird, dunnock, song thrush and tawny owl all showing worrying declines.

Among the wading birds, the mallard, oystercatcher and ringed plover are just some of those in decline.

Common ringed plover photo

Populations of the common ringed plover have declined substantially since the 1970s.

Only seabird populations appear to have remained relatively stable, although figures indicate that some species, such as the kittiwake and the arctic skua, are in decline. 

Habitat change is responsible for fewer nesting sites for the majority of the UK’s wild bird species. Food shortages have also been cited as a major cause of the decline in farmland birds. Agricultural intensification has had a huge impact on wild birds that favour wet grassland and moorland habitats, while less vegetation cover and scrub, overgrazing by deer, drainage of nearby farmland and changing winter climate may all be factors affecting vulnerable woodland bird populations.

There are some success stories. On farmland, wood pigeon and jackdaw populations have doubled, and stock dove and greenfinch numbers have risen by 50%. In the woodlands of the UK, the blackcap, great spotted woodpecker, green woodpecker, nuthatch and long-tailed tit are all thriving. In the wetlands, there has been a more than tenfold increase in the Svalbard light-bellied brent goose, and a sixfold rise in black-tailed godwit.

Great-spotted woodpecker

The great-spotted woodpecker population has more than doubled since the 1970s.

Richard Benyon, Minister for the Natural Environment in England, said: “Our bird populations are a good indicator of the wider health of our environment and it is clear that more needs to be done to support the recovery of farmland and woodland birds. Many people will have a part to play and we look forward to working with charities and landowners to reverse this trend.”

Read more about the decline in UK birds in this Guardian article.

Find out more about birds on ARKive.

Visit the British Trust for Ornithology Website.

Helen Roddis, ARKive Species Text Author


RSS feedArkive.org is the place for films, photos and facts about endangered species. Subscribe to our blog today to keep up to date!

Email updates

Sign up to receive a regular email digest of Arkive blog posts.
Preferred frequency:

Arkive twitter

Twitter: ARKive