Proof in the Poop

Priyanka Runwal

Top left – Red Fox (Vulpes vulpes) approaching a settlement&#x3B; Top right - Red Fox scat&#x3B; Bottom (left to right) – Pattern of medulla as seen     under the microscope for Goat, Rodent, Blue sheep (Pseudois nayaur) and Urial (Ovis orientalis) hair
Top left – Red Fox (Vulpes vulpes) approaching a settlement; Top right - Red Fox scat; Bottom (left to right) – Pattern of medulla as seen under the microscope for Goat, Rodent, Blue sheep (Pseudois nayaur) and Urial (Ovis orientalis) hair  (Photo: Hussain Reshamwala)

Rodents and hare are regular staples in Red Fox diets. In the wild, these comprise the natural prey base. But, increasingly, human-derived foods are becoming more popular among these opportunistic canids.

By examining the contents in Red Fox poop, a new study finds that these animals consume less wild prey when easily-procurable, human-subsidised alternatives are available in plenty. Not only that, in areas where such alternatives form a larger proportion of the diet, foxes were relatively more abundant. But one big hurdle to accessing these food resources is the presence of more dominant animals – feral dogs. 

A team of scientists from the Wildlife Institute of India (WII) and Stanford University, California, walked nearly 470 kilometres across the Trans-Himalayan region of India and bagged 1264 Red Fox scats. Fortunately for them, in these regions of low temperatures and rainfall, scats as old as six to seven months remain undeteriorated. 

The researchers wanted to assess how human settlements and activities like agriculture, animal husbandry and their by-products i.e. unmanaged garbage and free-ranging dogs impact Red Fox diet and their abundance. This was of particular interest as cold deserts are typically characterised by low availability of natural food resources.

Traces of undigested food in the poop gave the team clues to what foxes dined on. These included hair and bones of wild and domestic animals, feathers of wild birds and poultry, even plant material like apricots and cereal. Sadly plastic and rags too.

But by looking at a strand of hair in the Red Fox poop, how can one tell if it belongs to a wild animal or say, livestock? Every species has its own medullary hair pattern. When observed under a microscope, the medulla, or the innermost layer of hair, in goats, for example, shows fewer vacuoles and different disc like structures as compared to that of a blue sheep,” says Hussain Reshamwala, a PhD student at WII and lead author of the study. 

The scats revealed that rodents and hare continued to remain the main food item across the study region. Interestingly, however, local religious and cultural practices indirectly dictated what foxes could access near settlements and their numbers.

Chiktan, a site found to be most favourable for foxes, was dominated by Muslims, and saw a lot of discarded poultry and livestock, ideal to scavenge on. For religious reasons, these communities keep dogs away. Here, the fox numbers have shot up indiscriminately,” observed Hussain. Spiti, on the other hand, is a site of low human activity, and dominated by Buddhists, who are tolerant of all kinds of creatures. With dogs present, human-provided foods are less or not at all accessible to foxes, due to competition. The foxes here don’t stand a chance. Dogs chase or even kill them,” said Hussain.

This study reiterates the fact that garbage management is important, not only to keep human commensals such as the domestic dog in check, but also for wildlife, that can become dependent on such handouts,” said Abi Tamim Vanak, an expert in dog ecology and small carnivore biology at the Ashoka Trust for Research in Ecology and the Environment. 

So what if foxes are on the rise and scavenging on human food? Increasing populations may drastically bring down numbers of wild prey, and continue to remain insulated despite this decline, due to the supplementary food provisioning. With disruption of natural prey-predator cycles, there is little scope for recovery of species of the lower trophic levels, possibly leading to local extinctions in the Trans-Himalayan landscape.

This study was published in the Journal of Arid Environments 

Written By

Priyanka Runwal is an ecologist turned science journalist. She is now a science communication graduate student at the University of California, Santa Cruz. She has written for Science, Mongabay, Eos:Earth and Space Science News, Monterey County Herald, The Wire, The …