Wildlife Photographer of the Year: foxes on top of the world

Bao's image is impressive not only because it shows a rarely observed species, but because the animal is pictured hunting a marmot, which is not its usual prey. In fact, the foxes are entirely dependent on another species of small mammal known as the pika.

Rich Harris is a Section Manager for the Game Division with the Washington Department of Fish & Wildlife, but has spent time studying the foxes and other wildlife on the plateau. He helped to fill in gaps and correct many aspects on the biology of these high-altitude canines.

'I would begin by saying that most of the species in that part of the world are not very well studied,' says Rich.

'It is very difficult to know much about the foxes unless you can follow them, and that requires capturing them and putting radio collars on them. Until recently, Chinese science simply hadn't done a lot of this work.'

The Tibetan foxes were not the species Rich was originally focusing on. He was actually trying to catch and radio-collar the blue sheep that also live in the region, but he found that during the capture attempts, Tibetan foxes were also attracted to the bait laid down for the herbivores. 

By catching and collaring the foxes, as well as studying their faeces, Rich and his colleagues were able to refine what was previously known about the animals while adding to the existing knowledge of their behavior and physiology.

'They're well adapted to the cold temperatures,' explains Rich. 'For example, they have this luxurious-looking but actually very coarse fur covering their bodies. While it's effective in keeping the animal warm, it is not very soft.

'People think that the foxes have a strange-looking head, but if you look at the skull of a Tibetan fox it's actually very similar to the skull of a red fox.'

What is distinctive is their diet. While it was already known that the Tibetan foxes prey on the plateau pika (Ochotona curzoniae), Richard and his colleagues were able to show that the foxes are entirely dependent on them. 

'They are an obligate predator on pikas,' says Rich. 'The foxes can't exist without them. If you are in an area that otherwise would seem suitable, but there are no pikas, then you're just not going to find the foxes.'

It is this reliance on the pika that may threaten their survival. 

The 'roof of the world'

The Tibetan Plateau is a vast area covering 2.5 million square kilometres of central Asia. With an average elevation of 4,500 metres, it is both the biggest and highest plateau in the world.

Fringed on all sides by some of the tallest mountain ranges, the plateau encompasses different environments from alpine-like tundra to shrublands and forest, but the most common habitat is montane grassland.

While it at first glance it might not look like much could live in these sparse environments, the plateau supports a wide variety of life - you can find blue sheep and wild yaks grazing on the grasslands, as well as wolves, bears and snow leopards predating the herbivores.

The biggest challenge is often finding the animals in the first place, which helps to explain the lack of knowledge of these ecosystems.

But when Rich and his colleague were able to follow the foxes and spend more time up on the plateau, they revealed a whole host of relationships playing out on the steppes. One of these was the incredible association between Tibetan foxes and brown bears.

'I'm sure that local Tibetans must have seen it, but it was something that wasn't formally known to science,' explains Rich. 'Of course one of the reasons that it hadn't been reported before was because you've got two species - the bears and the foxes - that are difficult to observe.'

It turns out that when the bears are hunting the pikas, the foxes will follow the more powerful predators. When the bears then start to dig up the pikas from their burrows, the foxes will snap up any that try to escape.

'Almost invariably, whenever we were able to get a good look at a bear on the plateau, there was a fox nearby,' says Rich.

'The foxes obviously do fine without the bears, but if there is a bear then why would the fox bother with all the digging when they have this big brute who will dig the pikas up for them?'

The relationship is not quite symbiotic, however, as while the bears are not negatively impacted by the relationship, they're also not seemingly benefitting from it either.

Pika control

The foxes are not considered endangered, but figuring out just how many there are is a monumental task that has yet to be achieved. Currently the Tibetan fox is classified by the International Union for the Conservation of Nature as a 'least concern' species.

The animals are not substantially exploited for their fur due to its bristly nature, or hunted for their meat, but they still face an uncertain future. Despite not being directly targeted by humans they are at risk of becoming accidental targets.

The pikas on which they are so heavily dependent on have been subjected to eradication attempts, which could have knock on effects.

'The plateau pika is very common on the Tibetan Plateau, but they are viewed by Chinese policy as a pest,' explains Rich. 'Gradually over the years both Western and Chinese scientists have come to the realisation that the pikas are actually an important part of the ecosystem, even where they can be locally quite abundant.'

The pikas are seen by government and some livestock herders as competitors with domestic animals. There is also a view that their extensive burrowing behavior is somehow eroding and damaging the steppe, while their small, mouse-like appearance means that they are occasionally mistaken for rodents.

'So this led to a poisoning campaign, and as far as I know there still is one,' says Rich.  'They were putting out poison to kill what we figured was probably the principal prey of these foxes.

'If you do away with the prey then you pretty much do away with the predator as well.'

To date, there doesn't seem to have affected the foxes. But this is likely not because the eradication doesn't harm the canines - it's more a testament to the failure of the poisoning program in the first place.

The relationship between the foxes and the pikas highlights the fragility of the ecosystems that exist on the Tibetan Plateau, where it is threatened by human interference but also a warming climate.