In A Nutshell
It’s a common mistake in media: In commercials, films, and books, chimpanzees are often erroneously called monkeys. While related to monkeys, chimps aren’t actually monkeys at all. Instead, they’re part of a completely separate group of primates known as the great apes.
The Whole Bushel
Chimpanzees are often thought of as a type of monkey. In 2003, for example, Suburban Auto Group’s successful “trunk monkey” ad campaign featured a chimp as the mascot. The literary character Curious George is depicted as a large, tailless ape—and is almost exclusively referred to as a monkey.
But chimpanzees aren’t monkeys. Chimps are instead great apes, belonging to a family of mammals known as Hominidae. Other hominids include gorillas, orangutans, bonobos, and humans.
Hominidae forms one half of the super family Hominoidea, the other half of which is Hylobatidae. Hylobatidae is comprised of the lesser apes, which includes gibbons and siamangs.
These great apes and lesser apes are primates. Here, finally, the chimpanzees intersect with monkeys, who are also primates, along with lemurs, tarsiers, and several other species.
So what separates a monkey from a chimp, or any ape? Just about all monkeys are equipped with tails, which they skillfully use as a fifth appendage. And monkeys, while intelligent, pale in comparison to apes, who have a much larger brain-to-body ratio and use tools more frequently.
Additionally, the largest monkey, the mandrill (think Rafiki from The Lion King) caps out at just over 91 centimeters (3 ft). Chimps usually stand at around 1.7 meters (5.5 ft). Chimps also typically have longer lifespans, sometimes reaching human norms.
More evidence for distinction comes from genetics. Humans, chimps, bonobos, and gorillas are all closely related. Some scientists estimate that humans and chimpanzees share anywhere from 96–99 percent of the same DNA. Monkeys, on the other hand, are more distantly related to humans, sharing around 93 percent of the same DNA.
Somewhat ironically, when chimps go on the hunt, they tend to go after monkeys.
Show Me The Proof
Encyclopedia Britannica: Hominidae
HowStuffWorks: Is there a difference between monkeys and apes?
BBC: Ugandan Chimps Hunting (video)
Trunk Monkey Campaign