Hunger, Pregnancy and Bold: Why Female Gorillas Take Great Risks

Female gorillas not only follow the rules of hierarchy, but also challenge them when they fit their needs.

A new study based on 25 years of observations shows that female gorilla aggression is not just dominant, but about strategy. Whether it is pregnancy, lactation or group dynamics, gorillas regulate their aggressiveness based on their circumstances – sometimes even daring to face higher competitors. The survey results were held on July 23 Elifesuggesting that individual needs and social environment shape the way gorillas compete, thus providing rare insights into the development of risky behavior.

Gorillas don’t always beat them down

In most social animals, aggressive flows to hierarchy: the strong weak dominate. Indeed, this is true for most of the 6,871 aggressive interactions recorded in five gorilla groups in Uganda and Gabon. But nearly 42% of the time, aggression refers to up Social Ladder – From lower women to stronger women.

This is a surprising speed compared to other animals, and it does not violate the assumption that high-risk aggression is rare. “We found that individual needs and their social environment shape their aggression against individuals at different levels, which is predicted by the risk-raising theory,” said lead author Nikos Smit.

What drives gorilla adventure?

The answer seems to lie in energy and opportunity. Pregnant women, especially those in the last three months, are the women most likely to face higher ranking groups. Breastfeeding women also show aggressiveness to their stronger peers, but to a lesser extent. The authors argue that this difference may reflect the mother’s need to protect the baby by avoiding revenge.

Group composition also played a role. Women are bold when there are more men in a group. Perhaps the protection of men allows them to take risks to reduce fear of revenge. Instead, as female numbers swell, gorillas’ aggressiveness is aiming downward at low-level competitors, a mean target among the highly competitive crowd.

The main findings of this 25-year study:

• 42% of female aggression is made of social hierarchy
• There are more pregnant gorillas than any other group in three months
• More men in the group increase aggressiveness against strong competitors
• More and more women lead to safer, declining aggression
• Balanced women’s energy needs and baby safety

Gorillas adapt to aggression to adapt to this situation

These subtle strategies not only reflect the barbaric instinct. Researchers suggest female gorillas use what they call “aggressive heuristics” – simple decision-making rules are composed of internal needs and external conditions. When energy demand is high, or social support is available, gorillas calculate the risks and rewards of aggression, sometimes choosing bold choices.

“Overall, our results confirm that a person’s environmental needs and their social environment may influence their decision to engage in more risky behaviors,” said Martha Robbins, group leader at the Max Planck Institute for Evolutionary Anthropology.

This tells us about risks and social rules

This study challenges the notion that animal hierarchy is strictly enforced. Instead, they can be bent or poked when the conditions are correct. This reflects patterns seen in other species, including humans, where individuals with less choices sometimes boldly take resource action under pressure or with less choice.

From chimpanzees to crayfish to paper wasps, animals take the calculation risk when the stake is high. This study adds gorillas to the list, showing that individuals are willing to test restrictions even in stable social systems.

The last notes of the forest

If you find yourself looking at a group of gorillas, don’t just look at who is on the top. See who is doing the action and why. Under the quiet canopy of Bwindi or Loango, a silent calculus works. Sometimes, the loser becomes the most daring game for everyone.

Magazine: Elife
doi: 10.7554/elife.107093.2
Article title: Adventure Incentives Predicting Aggressive Heuristics in Female Gorillas
Publication date: July 23, 2025

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