Think back to the last time you were stolen from as a kid. Perhaps, you were the one doing the stealing. Regardless, imagine the tactics used to get the toy; maybe you screamed, cried, or even hit someone to get what you wanted. Primates, more specifically geladas, are no different than young humans when it comes to this form of aggression. However, it is adult females who display the aggression, and the item they’re fighting for is food.
Put yourself back into the shoes of a young child… Imagine there are 10 kids at recess and only 3 toys to play with, leading to a race for the toys and likely some fighting. Those who get the toys are the strongest, fastest, oldest, and/or smartest of the group. Similarly, animals in an environment with limited food are expected to compete for resources. In this food-limited condition, a hierarchy is expected, in which the females who succeed in obtaining the most food become the dominant individuals of a society.
What if there are 10 toys and 10 kids at recess? You might expect a lack of arguing as a result of the abundance of toys. However, this is not the case and there is still aggression involved. Why do you think this happens? In the kids at recess metaphor, fighting likely occurs due to one toy being newer or prettier than the others. Or, perhaps, one of the kids just really wants what their friend has. Rather than searching for another, possibly identical toy in a different location, kids will often steal from the friend they see with the desired toy.
This also occurs with dominant female geladas. Grasses are geladas’ primary food source and during the dry season, this source becomes limited. Researchers have proven that during these seasonal dry seasons, dominant females will wait for their subordinate group members to find and dig up underground storage organs (which are similar to potatoes or carrots beneath the ground), then steal from them. By doing this, they are able to minimize their energy output (with a lack of digging) and maximize energy input (by eating the nutrient rich food found underground).
Geladas quickly learn that both maintaining a full stomach and succeeding in society can be accomplished by stealing from friends. In fact, stealing food is characteristic of the top female geladas and can set one apart as a leader in their group. Luckily, as humans get older, they experience the opposite, and quickly learn that stealing and aggression will not propel you to the top.
Citations
Jarvey, Julia, Low, Bobbi, Haile, Abebaw, Chiou, Kenneth, Snyder-Mackler, Noah, Lu, Amy, Bergman, Thore, Beehner, Jacinta, Schneider-Crease, India. “Aggression Rates Increase Around Seasonally Exploited Resources in a Primarily Grass-Eating Primate”. October 12, 2023. Oxford Academic. https://academic.oup.com/beheco/advance-article/doi/10.1093/beheco/arad079/7308552?searchresult=1
