Similar social personalities strongly influence friendships in humans, yet we know relatively little about how animals choose their friends.

But a new study by researchers at City University of Hong Kong (CityUHK) investigating a unique free-ranging feral population of water buffalo on Lantau Island in Hong Kong has discovered that close spatial proximity serves as an indicator of friendship based on the predictive patterns of certain personality traits.

“Our research provides evidence that friendships among water buffalo can form among individuals with similar behaviours. These findings offer valuable insights into the evolution of friendships,” said Dr Debottam Bhattacharjee, a Postdoc in the Department of Infectious Diseases and Public Health in the Jockey Club College of Veterinary Medicine and Life Sciences (JCC) at CityUHK.

“Personalities and social relationships will be potentially important for understanding how buffalo use their habitats during different seasons (wet and dry) of the year with fluctuating food resources,” he added.

In essence, the CityUHK study indicates that individual female buffalo with similar personalities tended to exhibit higher spatial associations, i.e., spent more time physically close to each other during activities such as foraging, collective movement and resting.

The research has been published in iScience under the title “Personality homophily drives female friendships in a feral ungulate”.

The observational studies conducted by the CityUHK team revolved around observing female buffalo who spent more time in each other's company and also tended to display similar personality traits related to repeatable behavioural variables, i.e. social tension, vigilance and general dominance, explained Professor Alan McElligott, one of the paper’s co-authors and an expert on animal behaviour and welfare based in JCC’s Department of Infectious Diseases and Public Health.

How buffalo approached and avoided each other was labelled social tension; how they sat and moved around was labelled vigilance; and how they responded to others in their herd was labelled general dominance.

These traits were used to positively predict how long female buffalo would spend with each other, offering insights into how buffalo friendships form and are maintained, Professor McElligott added.

This research is vital because it has been shown in other studies that preferential strong social associations or friendships positively correlate with health, well-being, and survival benefits. In addition, there is growing evidence that human-like friendships can form in various species and that, as with humans, animal friendships can be stable, long-lasting and reach beyond kin relationships.

The CityUHK researchers point out that investigating social bonds among feral buffalo in Hong Kong is crucial for two main reasons. Some research, predominantly conducted in captivity, suggests buffalo are highly social animals, exhibiting complex patterns of affiliated behaviours and dominance-rank relationships.

“Moreover, understanding social behaviours and friendships of group living animals like buffalo improves welfare with broader implications for maintaining optimal health of those within the wider population,” said another co-author of the paper, Professor Kate Flay in JCC’s Department of Veterinary Clinical Sciences.

The major takeaway from this study, according to the CityUHK scientists, is the need to assess in greater detail how preferential close social relationships or friendships affect populations of feral buffalo and how what is learned can be applied to behaviours among other animals so that a more sustainable approach to animal welfare and conservation, especially for species under threat, can be maintained.

As a leading vet school in Asia, JCC jointly offers the Bachelor of Veterinary Medicine programme (BVM) in collaboration with Cornell University. The BVM is one of CityUHK’s flagship programmes and the first in Asia to achieve dual accreditation from the Royal College of Veterinary Surgeons and the Australasian Veterinary Boards Council.