Across the globe, the spread of human settlements has brought with it the rise of our most familiar animal companions — cats and dogs. These species have adapted remarkably well to living alongside us. Free-ranging dogs thrive on human food scraps, livestock remains, and shelter, enabling them to reach population densities far higher than many native carnivores can sustain. Domestic dogs often act as fierce competitors and predators of native wildlife, causing shifts in ecological balances, disrupting food chains, and contributing to local declines or even extinctions. Burgeoning populations of free-ranging dogs are affecting biodiversity, even in remote, fragile, high-altitude ecosystems of the Trans-Himalayas.
Spiti Valley is one such landscape, a cold desert of stark beauty and extreme conditions. Here, free-ranging dogs have become an increasing presence around human villages, drawn by food and shelter. A recent rise in free-ranging dog numbers has become a constant threat to native wildlife. There have been reports of them hunting wild ungulates, hybridising with wolves, and killing more livestock than the apex predators in the area. Red foxes in Spiti use villages, exploiting human food subsidies through livestock carcasses and garbage dumps, which bring them into direct conflict with the dogs.
To understand how red fox populations are coping with the growing presence of free-ranging dogs, a team of scientists led by Herman Ramesh conducted a field study to investigate how varying dog densities influence red fox behaviour. The researchers first surveyed thirty villages throughout Spiti Valley, recording the dog densities throughout. From this survey, they selected six villages representing a spectrum of dog densities, from sparsely populated areas with two to four dogs per square kilometre to densely occupied villages with more than thirty dogs per square kilometre.
Central to their study was an experimental setup involving cue-based foraging stations. Six baited feeding stations were placed on the outskirts of the villages, in areas frequented by foxes but with minimal recent dog activity to ensure that the primary visitors would be foxes. At these stations, the researchers played recordings of dog barks, providing auditory cues meant to simulate the presence of dogs. They also had other cues such as fresh dog scats, cow dung and cow moos at all the stations. Using motion-triggered cameras, the team observed how foxes responded to these treatments, focusing especially on vigilance behaviour—the amount of time foxes spent scanning their surroundings, pausing, or acting cautiously before feeding. Vigilance is a classic anti-predator strategy that allows animals to detect and avoid threats, but comes at the cost of less time spent feeding.
The results revealed that fox behaviour varied with the density of dogs in different areas. In villages with high dog densities, foxes responded strongly to the sound of barking, freezing, pausing, and sniffing the air in ways that showed marked increases in vigilance. This heightened alertness was especially pronounced in response to auditory cues–the presence of dog scat elicited a weaker reaction. By contrast, foxes in low dog-density villages showed little behaviour change regardless of dog cues.
“It was fascinating to see that red foxes only dialled up their vigilance when they heard barking—and only in villages teeming with dogs. That tells us foxes aren’t just generally jumpy; they’ve learned that an actual bark means real danger right now”, says Herman, lead author of the study. Scat cues were probably too vague to trigger the same alert. It must also be noted that in the high dog-density villages (high-risk sites), dog scat could be found everywhere close to villages, rendering them ineffective at providing nuanced information about dog presence, adds Herman. This behaviour change suggests that foxes dynamically assess risk based on local dog abundance and adjust their anti-predator strategies accordingly, demonstrating impressive behavioural flexibility.
But vigilance alone was not the foxes’ only survival strategy. The researchers also deployed camera traps to monitor when foxes and dogs visited food-rich sites. The data showed that foxes and dogs rarely appeared at the same time, especially in villages with medium to high dog densities. This phenomenon, known as temporal partitioning, means that foxes shifted their activity patterns to avoid direct encounters with dogs by becoming more nocturnal, active primarily during times when dogs, which are mostly diurnal, were less likely to be around. At high dog-density sites, the temporal overlap between fox and dog activity was especially low, showing that foxes carefully timed their visits to minimise risk. At medium-density sites, a similar but less pronounced pattern was observed, while at low dog-density villages, the overlap was higher, reflecting less need for temporal avoidance. This strategy of sharing space by dividing time allows foxes to coexist with dogs in a way that reduces dangerous confrontations.
Perhaps the most surprising finding from the study was that fox abundance increased with dog density. “High dog-density sites are also sites with more food resources. The availability of more food, coupled with the ability of these foxes to minimise encounters with dogs, might allow these locations to support higher fox populations,” says Herman.
It is also possible that the higher fox relative abundance reported from high dog-density sites could be the result of foxes at these sites moving more (thus, getting captured on more cameras, and inflating our encounter rates). These sites have more dogs, which means more competitors. It is possible that foxes offset living with more competitors by simply moving between more food sources in a single night. So our cameras may be recording both a true rise in fox numbers and busier fox traffic, which explains why detections spike in high-dog areas, he adds. For foxes, the rewards of accessing these resources appear to outweigh the risks posed by dogs. By combining heightened vigilance with clever timing, the foxes have learned to navigate a landscape dominated by their canine competitors.
While foxes seem to manage these pressures, free-ranging dogs remain a threat to other native wildlife, including ground-nesting birds, small mammals, and even endangered snow leopard cubs. Managing dog populations in these fragile, high-altitude ecosystems is critical to conserving biodiversity.
“Our findings suggest red foxes can coexist with free-ranging dogs, yet the bigger issue is the human food subsidies that attract both species to garbage dumps. These sites represent important resource-rich islands, especially in harsh, arid landscapes. They thus become meeting points for dogs, livestock and wild carnivores, greatly increasing disease-transmission risks. Mesocarnivores like foxes may escape direct attacks through fine-scale avoidance strategies, like vigilance, but sustained contact with pathogen-carrying dogs could still trigger population declines via spill-over infections. Rigorous waste and garbage management is therefore essential to curb dog numbers and protect native carnivores,” says Kulbhushansingh Suryawanshi, senior author of the study.
Link to the study: https://royalsocietypublishing.org/doi/full/10.1098/rspb.2025.0333
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