Who rests with whom? Sex composition and group demography shape resting associations in free-ranging dogs

In the world of animal behavior, scientists often look at how individuals choose to spend their time together. When animals rest, they are vulnerable, so the decision of who to lie down next to is rarely random. It is a social signal that reveals who trusts whom, who competes with whom, and how the group holds itself together. For free-ranging dogs, which live outside the control of human households and form loose, fluid communities, these choices are particularly interesting. Researchers have long wondered what drives these dogs to rest in specific clusters. Is it simply a matter of who is available, or do specific traits like gender or age create invisible lines of preference? Understanding these patterns helps us see how social bonds form in animals that are not bound by a single owner, offering a window into the natural social lives of one of the most common animals on Earth.

To answer these questions, a team of researchers spent several years observing free-ranging dogs in West Bengal, India. Between 2019 and 2023, they watched 26 different groups of dogs as they went about their daily lives. The scientists did not interfere with the animals; instead, they took regular snapshots of the scene, noting exactly which dogs were resting near each other at any given moment. By counting how often specific pairs of dogs were found resting together, the team could measure the strength of their connection. They then used these observations to test whether the sex of the dogs, their age, the total number of dogs in a group, or the balance of males and females influenced who rested with whom.

The results revealed a clear pattern in how these dogs organized their resting spots. The strongest bonds were found between female dogs; they tended to rest together more often than any other combination. Male dogs, on the other hand, showed a distinct preference for keeping their distance from one another when it came to resting, forming the weakest associations of all. Surprisingly, pairs made up of one male and one female rested together just as frequently as pairs of females. This suggests that while males avoid each other, they are quite comfortable resting alongside females. The researchers also found that the size of the group mattered. As the number of dogs in a group grew larger, the strength of the connection between any two specific dogs tended to weaken, likely because there were simply more options for where to lie down. Conversely, groups with a higher proportion of males compared to females showed stronger overall associations between individuals.

Age, however, did not play the role some might expect. The study found no evidence that the life stage of the dogs—whether they were puppies, adults, or older dogs—affected who they chose to rest with. The social structure seemed driven more by gender and group makeup than by age. When the researchers looked at the broader social network of each dog, measuring how well-connected an individual was to the rest of the group, they found that these connections did not change based on the dog's sex or the time of year. Some dogs were simply more central to the group's social web than others, but this status was not tied to whether they were male or female.

While the data clearly showed that mixed-sex pairs were among the strongest relationships in these groups, the researchers remain cautious about why this happens. The prominence of male-female pairs could mean that these dogs actively prefer each other's company, or it could simply be a reflection of the group's composition. If a group has many males and many females, mixed pairs will naturally occur more often, regardless of personal preference. The study confirms that sex and group demographics shape how these dogs rest, but it stops short of declaring that mixed-sex pairs are a deliberate choice. To know for sure if these dogs are choosing each other over others, future studies would need to control for the simple availability of companions. For now, the picture is clear: in the quiet moments of rest, free-ranging dogs sort themselves out by gender and group size, creating a social map where females stick close, males keep apart, and mixed pairs bridge the gap.