Shy or risk-averse female kangaroos prefer to be in larger groups, but have fewer friends, while their bolder counterparts are happy in smaller groups and are more likely to seek out new friends, researchers from the University of Queensland found in a new study.
Dr. Emily Best, a researcher at the School of Biological Sciences, believes kangaroo social networks could provide insight into the evolution of personality differences among humans.
The study findings were published in the academic journal Behavioral Ecology (citation below).
Dr. Best and colleagues studied the friendships of female kangaroos over a period of eighteen months to determine why personalities differ and how these differences might affect behavior.
The shyer kangaroos prefer to stay within a large group.
“Individual female kangaroos differ consistently in both the sizes of groups in which they feed and in how shy or bold they are.”
“Bolder females seem more comfortable in smaller groups and will seek out their ‘friends’, while shyer females opt to remain in larger groups where there is less risk of predation.”
“Similar findings have been made for fish in captivity and domestic mammals, but never for mammals in the wild. These results increase our understanding of how aspects of personality affect each other, which will lead to better understanding of why such personality differences have evolved.”
Personality and genes
Personality, which involves consistent behavioral differences among individual animals, is believed to be at least partially determined by genetics.
Humans show the same types of individual differences which are partly driven by genetics, the researchers explained.
The bolder kangaroos have more friends and prefer to be in smaller groups. (Photo: Emily Best)
Dr. Best said:
“It is likely that personality evolved in similar ways in our ancestors as in animals, so studying personality in kangaroos will give us insight into humans.”
The team members observed 171 wild female eastern grey kangaroos over 18 months. They identified friendships by analyzing which other females each kangaroo made a special effort to feed with.
They measured a kangaroo’s boldness, or propensity for risk-taking, by having a human walk toward the animal at a consistent speed and measuring the distance at which it would flee.
Friendly kangaroos are bolder
They found the bolder kangaroos had more female friends and allowed unknown humans to get nearer to them, compared to the shy ones.
Anne Goldizen, associate professor at the School of Biological Sciences, believes that the shyer and more risk-averse females were reluctant to leave the foraging group in search of friends because it would exposed them more to predators.
Prof. Goldizen said:
“Therefore their associations, or friendships, are weaker than those of individuals who go out of their way to be sociable.”
“This work is part of a long-term study which will increase our understanding of why animals form social bonds.”
In their Abstract in the journal, the authors wrote:
“Shy females had significantly larger mean foraging group sizes. After controlling for gregariousness and space use, shy females had fewer preferred associates than bolder females. Therefore, boldness can have an important influence on the size and composition of foraging groups and thus social networks, in wild mammals.”
Citation: “Shy female kangaroos seek safety in numbers and have fewer preferred friendships,” Emily C. Best, Simon P. Blomberg and Anne W. Goldizen. Behavioral Ecology. First published online February 12, 2015. DOI: 10.1093/beheco/arv003.