Chimpanzees (Pan troglodytes) are emotional, violent, smart, and social—no wonder they’re our closest relatives. But theirs is a side of the family it might be best not to invite over for dinner. Here are a few facts about chimps, our evolutionary next of kin.
1. Chimpanzees are one of the four great apes.
The other three in the category are bonobos, orangutans, and gorillas. Technically, humans are considered great apes, too—we all belong to the family Hominidae. Chimps are more closely related to us than to gorillas, sharing more than 98 percent of our genes.
2. Chimpanzees aren't picky eaters.
Chimps snack on as many as 200 different foods, such as fruits, nuts, seeds and insects, as well as small mammals, including other monkeys. Chimpanzees are also hunted by humans for “bushmeat,” a term meaning wild animals potentially carrying communicable diseases that could be passed on to human consumers.
3. Chimpanzees are super-social.
Chimps wouldn’t like social distancing. They live in communities that range in size from 20 or fewer to more than 100 individuals. Unlike gorilla groups, chimp communities may have several adult males and females and assorted family units. When they reach sexual maturity, females may migrate to other groups while males stay with the group they were born into.
4. Grooming is the chimpanzee love language.
Grooming—essentially picking over a chimp’s fur and removing parasites, dirt, and dead skin—calms chimpanzees, keeps them healthy, and reinforces social bonds. Low-ranking chimps groom high-ranking chimps to gain protection or other social benefits. If a low-rank individual is grooming a companion of the same social status and sees a higher-rank chimp pass by, the groomer will stop the activity. It may be that he doesn’t want to waste time grooming a companion who won’t offer the same social protections as the high-ranking bystander might.
5. Chimpanzees are a rainforest-dwelling species.
The four subspecies of chimp share the largest range of the great apes (excepting humans), spanning tropical and mountain rainforests in West and Central Africa. Within their ranges, chimps patrol their specific territory. Groups of males will walk along the border of their territory and may attack if they encounter neighbors or rival groups. If they win a fight, they may expand their territory.
6. Thanks to their anatomy, chimpanzees are poor swimmers.
Being top-heavy with a low body fat percentage means they tend to sink in water. Like orangutans, their arms are longer than their legs. When they walk on all fours, they support themselves with their knuckles. Chimps can also walk upright like we do for short distances.
7. Only humans purposefully use tools more often than chimpanzees.
In the 1960s, Jane Goodall was the first to observe chimps in Tanzania’s Gombe National Park making and using tools. She saw them stripping leaves off twigs [PDF] and dipping the sticks into termite mounds, then pulling out the sticks covered in snackable insects. Further research showed that the Gombe chimps used objects, such as leaves or rocks, as tools for nine different purposes.
Chimps in other regions use tools in distinct ways, such as using sticks to extract honey from beehives. In 2007, archaeologists working in Côte d’Ivoire in West Africa discovered rocks that a prehistoric chimp community had used to crack nuts.
8. Chimpanzees are an endangered species.
No more than 300,000 remain in the wild across their range. Chimps are protected by national and international laws, but enforcement is weak. Those that live on reserves may not be well protected from poaching, one of the main threats to the species. Other factors in the decrease in chimp population include infectious diseases and habitat loss from logging and agriculture. Even in areas where forests are intact, a large human footprint—high population plus infrastructure—correlates with fewer chimps.
9. The National Institutes of Health no longer supports using chimpanzees in scientific research.
Chimpanzees have been used in biomedical research in the U.S. since the 1920s [PDF], a trend that ramped up during the AIDS crisis in the 1980s and 1990s. In 2013, the National Institutes of Health announced that it would decrease the number of chimps used in research. Two years later, NIH said that it would no longer fund research using chimps. More than 300 of the animals have been retired to the Federal Sanctuary System’s national sanctuary in Louisiana.