Kangaroo Facts: Roos Have Complex, Longer Social Relationships Especially After Having a Joey

Kangaroos are among Australia's most iconic and recognizable animals, but how much do we really know about their social behavior?

A recent study by researchers from UNSW Sydney revealed some surprising insights into the relationships and personalities of eastern grey kangaroos, one of the country's most common and widespread species.

The study, published in the journal Animal Behaviour, showed that kangaroos have stronger bonds to one another than previously thought, and that these bonds can last for several years.

The study also found that kangaroo mothers become more social when caring for joeys, contrary to the previous assumption that they would become more solitary to avoid predation.

How the researchers studied kangaroo sociality

(Photo : Matt Jelonek/Getty Images)

The researchers monitored a population of around 130 eastern grey kangaroos near Wollar in New South Wales for six years, from 2016 to 2021.

They used a non-invasive method of taking photographs of every individual kangaroo in the population, and then identifying them by the unique shape of their ears.

They also recorded the sex, age, and reproductive status of each kangaroo, as well as their group size and composition.

The researchers then analyzed the photographs to see which kangaroos associated with each other, and how often they did so.

They also calculated a social score for each kangaroo, based on how many other kangaroos they associated with and how "popular" these associates were.

The social score was a measure of how central or peripheral a kangaroo was in the population's social network.

Also Read: Kangaroo Crisis: Experts Warn of Mass Starvation and Extinction Risk for Australia's Iconic Marsupials

What the researchers found out about kangaroo relationships

The researchers found that kangaroo relationships were more complex than previously thought. Some of the main findings were:

•  Kangaroos had different personalities when it came to sociability. Some kangaroos were consistently more social than others, while some changed their sociability from year to year.
•  They formed long-term friendships that lasted for multiple years. These friendships were more common among females than males, and were more likely to occur among kangaroos that had higher social scores.
•  Kangaroo mothers became more social when they had joeys in their pouch or at foot. This was opposite to what the researchers expected, as they thought that mothers would become more solitary to reduce the risk of predation on their offspring. The researchers suggested that mothers might benefit from being more social by gaining access to better resources, protection, or information from other females.
•  Environmental factors, such as rainfall and vegetation, influenced kangaroo sociality. Kangaroos tended to be more social in wetter years and in areas with more grass cover, as these conditions provided more food and water availability.

The study demonstrated a novel and feasible technique for studying the social behavior of wild animals using photographic surveys.

They also suggested that their findings could have implications for the conservation and management of kangaroo populations, as well as for understanding the evolution and ecology of sociality in mammals.

Related article: Kangaroos Are All Left-Handed?