Sunday, Sept. 24, 2017, is the inaugural World Gorilla Day, an observance calling attention to the plight of gorillas in the wild, which are rapidly facing extinction, and things that can be done to protect them. World Gorilla Day coincides with the 15th anniversary of the opening of the Karisoke Research Center, the site of the longest-running field study of gorillas established by famed primatologist Dian Fossey and run by The Dian Fossey Gorilla Fund.



Fossey, who began her study of mountain gorillas in 1966 in the jungles in the hills of the Virunga Volcanoes region shared by Rwanda, Uganda and Congo, is widely credited with changing both how scientists and the public at large view gorillas. She lived with them for nearly 20 years, finding they live much as human families do. Her murder in 1985 remains unsolved. A film based on Fossey's research and life, "Gorillas in the Mist," sparked both a wave of curiosity about gorillas and the advent of "gorilla tourism," which helps protect them against poachers, one of the main threats to their survival.

With that protection, the mountain gorilla population is increasing, but still numbers only about 880 individuals, according to the World Wildlife Foundation. Photo by Brent Stirton_Getty Images for WWF-Canon/Getty Image News There are two species and two subspecies of gorilla: western lowland gorillas and the subspecies Cross River gorilla, and the mountain gorilla and the eastern lowland gorilla, also known as Grauer's gorilla.

The rarest of the gorillas are Cross River gorillas, and only about 250-300 remain, isolated in a small area of highland forest straddling the border of Cameroon and Nigeria. Eastern lowland gorillas are in steep decline, now numbering fewer than 4,000, and the western lowland gorillas are the most common, with about 100,000 remaining. Photo by Brent Stirton/Getty Images for WWF-Canon Here are seven amazing facts about gorillas:



1. They're not as tough as you think: Although pop culture portrays them as fierce, aggressive killers, they are shy, gentle and peaceful, and generally avoid human confrontation. When surprised by a human, they're likely to roar loudly, but it's just a bluff. And they may race toward a human, but stop just short if the human is submissive and backs away. You really don't want to try to tangle with a gorilla, though, because they're powerfully strong. How strong are gorillas? That's a riddle yet to be answered because comparisons aren't easily made. Estimates are that a male silverback is 10 times stronger than a human male, and others say the silverback is 27 stronger. What is known is that gorillas don't have much more muscle tissue than humans. 2. Gorillas can't speak and here's why: If you've watched any of the "Planet of the Apes" movies, you've seen gorillas and other types of great ape speaking, just as humans do. And while it's true that gorillas and humans have almost identical DNA — humans and gorillas are about 98 percent similar in genetic makeup, National Geographic reported — the space between gorillas' higher larynx and soft palate is too small for sound to resonate. 3. But they do communicate: Gorillas have their own language — screams, hoots, roars and growls for sure — but also softer, subtler sounds like grunts and chuckles, depending on whether they are playing, eating, angered or alarmed. Gestures — chest-beating, lunging, throwing objects, staring, lip-tucking, sticking out their tongues, running sideways, slapping and rising to bipedal stance — are also part of their language repertoire. And gorillas also have an understanding of spoken language. "If you define language as having nouns and verbs, there isn't evidence of that in the wild, but in captive language studies apes, including gorillas, very quickly seem to understand syntax and learn the gestures and symbols for particular things and learn to associate human words, spoken words with things," Ian Redmond, a research assistant for Fossey with more than 30 years experience as a field biologist, told BBC. The most famous "talking gorilla" is Koko, who communicates using American Sign Language. Photo by Matt Cardy/Getty Images News/Getty Images 4. Eureka! Wild gorillas are tool users: Captive gorillas have been taught to use tools, but tool use by wild gorillas was not seen in the wild until 2014, BBC reported. After a young female named Lisanga watched an older male, Kigoma, attempt to collect driver ants from the ground and saw them bite him and scare him away, she tried the same technique and also was bitten. But Lisanga didn't give up, instead grabbed a twig, stuck it in the ground, extracted it and then licked off the ants and wasn't stung, according to a paper in the American Journal of Primatology. The milestone moment was observed and recorded by Dr. Jean-Felix Kinani, the head veterinarian with Gorilla Doctors, which works with wildlife authorities in gorillas' African range countries to monitor their health.