by To survive, animals compete for resources, be it for food, mating partners or territory. But a recent groundbreaking study shows that chimpanzees and gorillas form friendships, some of which last at least 20 years. They play, eat and socialize together.
It is the first study of its kind to see such peaceful and long-term associations among monkeys. A team of scientists led by Crickette Sanz of Washington University in the United States made this discovery using over 20 years of data from the Nouabalé-Ndoki National Park in the Republic of the Congo.
We know that many animals are fiercely territorial, including chimpanzees and gorillas. Both species will defend their territories from other groups. Chimpanzees kill members of other chimpanzee groups that stray into their territory. And between 2014 and 2018, researchers found that a group of chimpanzees in Gabon, Central Africa, had killed young gorillas and even saw a female chimpanzee eating a gorilla cub.
So, I was surprised to learn from the new study that the two monkey species sometimes form lasting unions. The fact that these species can live peacefully in one area for decades and dine for the other in another region is fascinating.
Go out
Young adult male primates tend to be more outgoing and inquisitive than other members of their ranks. In the new study, the scientists found that juveniles often seek out particular members of other species to play, sometimes walking long distances (over 300 meters) alone to do so.
Mixing with another group or species can be risky. But both species were relaxed around each other instead of being on the alert to attack. The study also found that female chimpanzees and gorillas with young offspring were also related to each other, as were the entire spectrum of age groups. Chimpanzees have even been seen mimicking the classic gorilla chest throb. Neither species has ever sounded red flags when they met.
Food-oriented friendships
The next task now for the researchers is to select what exactly is different between the behavior of chimpanzees and gorillas in home ranges in the Republic of Congo and Gabon (about 1,000 km away).
Chimpanzees and gorillas eat similar foods, and most of the lovable interactions scientists have recorded in the Republic of Congo involved monkeys feeding on figs and other fruit trees.
Why should you tolerate someone breaking into your buffet? Figs are high energy and a valuable resource. The trees bear fruit for only four or five days. And fruiting is asynchronous (which means they fruit at random). If gorillas or chimpanzees find mature ones, perhaps it is better to tolerate each other than to waste energy chasing each other. Combining knowledge or staying close enough to intercept what others are doing could also give them an edge. Chimpanzees tend to eat a lot more fruit than gorillas. Yet these gorillas in the Republic of the Congo have a higher-than-normal fruit-based diet which could help explain their unusually friendly behavior with local chimpanzees.
I watch your back
Leopards are predators of both species, so it pays to have as many alert eyes as possible. Both species have even responded to the other’s predatory warning calls. They shared information on predators and feeding sites.
Many other species work together to escape predators. Antelopes, wildebeest and zebras gather by the thousands each year to travel together across Tanzania and Kenya in search of good pastures and safe places to breed. And we see alliances between other monkey species as well, such as the putty-nosed monkeys and the Diana monkeys of Taï National Park, Ivory Coast in West Africa, usually to increase feeding opportunities or predator detection. .
These findings could provide clues as to how humans may have evolved. Different species of ancient humans may also have shown tolerance and friendship between different species despite similar overlaps in diet and competition. Hybrids of skeletons of different human species have been found. Friendships can also reduce stress for humans, and owning a pet can boost mental health. So it would be fascinating to see if monkeys enjoy these benefits from having a friend of another species as well.
Don’t take monkeys for granted
As far as we know, these interactions may be more common than reported. In places where chimpanzees and gorillas share habitat, researchers often study only one or the other species. Species that are not used to people often flee from the sight of the research team. Researchers often work with species for years before they get used to people.
Chimpanzees are considered endangered while gorillas are listed as critically endangered on the International Union for Conservation of Nature’s Red List of Threatened Species. The study shows how full of surprises our close relatives are and how important it is to preserve the natural world so that their fascinating behaviors are not lost before we even know them.
This article was republished by The Conversation under a Creative Commons license. Read the original article.
Chris Young does not work, consult, own stock or receive funding from any company or organization that could benefit from this article and has not disclosed any relevant affiliations beyond their academic tenure.
