December 14 is International Monkey Day — an unofficial holiday that celebrates monkeys and “all things simian,” including other non-human primatessuch as apes, tarsiers, and lemurs. Monkey Day was created and popularized by artists Casey Sorrow and Eric Millikin, in order to spread awareness for the animals, and to show love and care for them. It is celebrated worldwide and often known as World Monkey Day.
Monkey Day was created and popularized by artists Casey Sorrow and Eric Millikin, beginning in 2000 when they were art students at Michigan State University. Sorrow jokingly scribbled Monkey Day on a friend’s calendar, and then they first celebrated the holiday with other MSU art students. The holiday gained notoriety when Sorrow and Millikin began including Monkey Day in their artwork and alternative comics that they published online and exhibited internationally along with other artists.
Since then, Monkey Day has been widely celebrated across countries such as the United States, Canada, Germany, India, Pakistan, Estonia, United Kingdom, Colombia, Thailand, Turkey, and Scotland. Hallmark Cards describes the holiday as a “day when monkey business is actually encouraged.” The Washington Post describes Monkey Day as a day to “learn something about these adorable and highly intelligent primates. Or you could use this day to act like a monkey.”
Monkey Day’s celebrants and supporters include Jane Goodall, Greenpeace, National Geographic, the National Portrait Gallery in London, the Louvre Museum, and the Metropolitan Museum of Art.
Many zoos hold annual Monkey Day events. For example, the Lahore Zoo in Pakistan holds an annual World Monkey Day celebration that includes art competitions and educational events about monkeys, including over a hundred children wearing monkey masks, poetry readings about monkeys, and performances to highlight the threats monkeys face as well as monkey evolution. The Tallinn Zoo in Estonia celebrates Monkey Day by auctioning artwork created by chimpanzees and performing intelligence tests on Japanese macaques. The Indira Gandhi Zoological Park in India organizes Monkey Day programs to educate children about wildlife issues and encourage people to adopt monkeys. The Faruk Yalçın Zoo and Botanical Park in Darıca, Turkey, hosts Monkey Day events to draw attention to declining monkey populations. The Edinburgh Zoo in Scotland uses Monkey Day events including monkey story telling to raise awareness of the dangers that primates face worldwide. Since 2009, the Colombian Association Primatological APC (for its acronym in Spanish) has celebrated Monkey Day.
Prominent artists like Sorrow, Millikin, Rob Balder, and David Malki have created Monkey Day themed comics and artwork.
For Monkey Day 2012, USA Weekend published The 12 Stars of Monkey Day, a series of paintings by Eric Millikin that were “in part inspired by the many pioneering space monkeys who rode into the stars on rockets, leading the way for human space flight.” In 2013, Millikin created a mail art series where he mailed Monkey Day cards to strangers, including Koko the sign-language gorilla and President Barack Obama. For Monkey Day 2014, Millikin created a 3D monkey experience. Since 2016, Millikin has created the Danger Beast series of street art portraits of endangered animals created out of endangered plants, including a portrait of Harambe the gorilla made from Venus flytraps.
In addition to his monkey-themed artwork, Sorrow also maintains a comprehensive Monkeys in the News blog with stories on topics like monkey attacks, monkey smuggling, and monkey science. Every Monkey Day, Sorrow’s Monkeys in the News blog counts down the previous year’s “top 10 Monkey and Primate News highlights”
Often, celebrations involve raising money for primate-related issues. In 2008, the official Monkey Day celebrations included an art show and silent auction to benefit the Chimps Inc. animal sanctuary; the show and auction included art by human artists as well as paintings from chimps Jackson and Kimie, residents of the sanctuary. The Biddle Gallery in Detroit also celebrated Monkey Day in 2008 with an annual Monkey Day art sale that included a free banana with each purchase. For 2013, the International Primate Protection League celebrated Monkey Day and raised money for conservation by offering life-drawing classes where people learned to draw portraits of Gary the gibbon. Greenpeace says “Monkey Day is the perfect time to swing into action and help protect primate habitat by becoming a forest defender.”
The holiday is also celebrated with costume parties intended to help draw attention to issues related to simians, including medical research, animal rights, and evolution. Often there are competitions to see who has the best costumes, who can act like a monkey the longest or perform the most amusing impression of one, or speed knitting of monkey dolls. The holiday cuts across religious boundaries and provides opportunities to share monkey stories and contemplate our simian relatives. Other Monkey Day activities include going on shopping sprees for Paul Frank “Julius the Monkey” fashions, eating Ben & Jerry’s Chunky Monkey ice cream, and spending the day at the zoo. When monkeys cause trouble, such as a monkey driving away in a stolen bus, the monkey is often said to be honoring the traditions of Monkey Day.
In 2005, Peter Jackson’s film King Kong was released on the fifth anniversary of Monkey Day. For Monkey Day 2014, the creators of Night at the Museum: Secret of the Tomb released a short feature starring Crystal the Monkey. Mainstream American films like King Kong and the Planet of the Apes movies are popular at Monkey Day parties, as well as monkey Kung Fu films like Lady Iron Monkey. Monkey-themed songs, such as Major Lance’s “The Monkey Time” and The Rolling Stones song “Monkey Man”, are also part of Monkey Day festivities.
Liberia released its first pictorial stamps featuring wildlife animals in 1892. The beautifully engraved bicolored stamps would prove to be very popular and increasing numbers would be issued for years to come. These often received various overprints and surcharges as well. In 1906, 13 denominations of a 1905 definitive set were overprinted in various colors for use as Official stamps by the Liberian government, this includes one of only two stamps in my collection featuring any kind of simian (unless one counts the Ramakian stamps from Thailand featuring the Monkey King mask or character). Scott #O48 has a black OS overprint on the beautiful 5-cent ultramarine and black stamp portraying a chimpanzee.
The taxonomical genus Pan (often referred to as chimpanzees or chimps) consists of two extant species: the common chimpanzee and the bonobo. Together with humans, gorillas and orangutans they are part of the family Hominidae (the great apes). Native to sub-Saharan Africa, common chimpanzees and bonobos are currently both found in the Congo jungle, while only the common chimpanzee is also found further north in West Africa. The two species are on the IUCN “red list” of critically endangered species and in 2017 the Convention on Migratory Species, which was held in The Philippines, selected the common chimpanzee for special protection.
They were once considered to be one species; however, since 1928, they have been recognized as two distinct species: the common chimpanzee (P. troglodytes) who live north of the Congo River, and the bonobo (P. paniscus) who live south of it. In addition, P. troglodytes is divided into four subspecies, while P. paniscus has none. Based on genome sequencing, the two extant Pan species diverged around one million years ago. The most obvious differences are that chimpanzees are somewhat larger, more aggressive and male-dominated, while the bonobos are more gracile, peaceful, and female-dominated.
Their hair is typically black or brown. Males and females differ in size and appearance. Both chimps and bonobos are some of the most social great apes, with social bonds occurring among individuals in large communities. Fruit is the most important component of a chimpanzee’s diet; however, they will also eat vegetation, bark, honey, insects and even other chimps or monkeys. They can live over 30 years in both the wild and captivity.
Chimpanzees and bonobos are equally humanity’s closest living relatives. As such, they are among the largest-brained, and most intelligent of primates; they use a variety of sophisticated tools and construct elaborate sleeping nests each night from branches and foliage. They have both been extensively studied for their learning abilities. There may even be distinctive cultures within populations. Field studies of Pan troglodytes were pioneered by primatologist Jane Goodall. Both Pan species are considered to be endangered as human activities have caused severe declines in the populations and ranges of both species. Threats to wild panina populations include poaching, habitat destruction, and the illegal pet trade. Several conservation and rehabilitation organizations are dedicated to the survival of Pan species in the wild.
The first use of the name “chimpanze” is recorded in The London Magazine in 1738, glossed as meaning “mockman” in a language of “the Angolans” (apparently from a Bantu language); a Zone H Bantu language has the comparable ci-mpenzi. The spelling chimpanzee is found in a 1758 supplement to Chamber’s Cyclopædia. The colloquialism “chimp” was most likely coined some time in the late 1870s.
The common chimpanzee was named Simia troglodytes by Johann Friedrich Blumenbachin 1776. The species name troglodytes is a reference to the Troglodytae (literally “cave-goers”), an African people described by Greco-Roman geographers. Blumenbach first used it in his De generis humani varietate nativa liber (“On the natural varieties of the human genus”) in 1776, Linnaeus 1758 had already used Homo troglodytes for a hypothetical mixture of human and orangutan.
The genus name Pan was first introduced by Lorenz Oken in 1816. An alternative Theranthropus was suggested by Brookes1828 and Chimpansee by Voigt 1831. Troglodytes was not available, as it had been given as the name of a genus of wren (Troglodytidae) in 1809. The International Commission on Zoological Nomenclature adopted Pan as the only official name of the genus in 1895. The name is a reference to Pan, the Greek god of nature and wilderness.
The bonobo, in the past also referred to as the “pygmy chimpanzee”, was given the species name of paniscus by Ernst Schwarz (1929), a diminutive of the theonym Pan.
In his book, The Third Chimpanzee, J. Diamond proposes that P. troglodytes and P. paniscus belong with H. sapiens in the genus Homo, rather than in Pan. He argues that other species have been reclassified by genus for less genetic similarity than that between humans and chimpanzees.
Common Chimpanzees are found almost exclusively in the heavily forested regions of Central and West Africa. With at least four commonly accepted subspecies, their population and distribution is much more extensive than the Bonobos, found only in Central Africa, south of the Congo River and north of the Kasai River (a tributary of the Congo), in the humid forests of the Democratic Republic of Congo of Central Africa.
Research by Mary-Claire King in 1973 found 99% identical DNA between human beings and chimpanzees. For some time, research modified that finding to about 94% commonality, with some of the difference occurring in noncoding DNA, but more recent knowledge states the difference in DNA between humans, chimpanzees and bonobos at just about 1%–1.2% again.
A chimpanzee’s arms are longer than its legs. The male common chimp stands up to 3.9 feet (1.2 meters) high. Male adult wild chimps weigh between 40 and 60 kilograms with females weighing between 27 and 50 kg. When extended, the common chimp’s long arms span one and a half times the body’s height. The bonobo is slightly shorter and thinner than the common chimpanzee, but has longer limbs. In trees, both species climb with their long, powerful arms; on the ground, chimpanzees usually knuckle-walk, or walk on all fours, clenching their fists and supporting themselves on the knuckles. Chimpanzees are better suited for walking than orangutans, because the chimp’s feet have broader soles and shorter toes. The bonobo has proportionately longer upper limbs and walks upright more often than does the common chimpanzee. Both species can walk upright on two legs when carrying objects with their hands and arms.
The chimpanzee is tailless; its coat is dark; its face, fingers, palms of the hands, and soles of the feet are hairless. The exposed skin of the face, hands, and feet varies from pink to very dark in both species, but is generally lighter in younger individuals and darkens with maturity. A University of Chicago Medical Centre study has found significant genetic differences between chimpanzee populations. A bony shelf over the eyes gives the forehead a receding appearance, and the nose is flat. Although the jaws protrude, a chimp’s lips are thrust out only when it pouts.
The brain of a chimpanzee has been measured at a general range of 282–500 cubic centimeters. The human brain, in contrast, is about three times larger, with a reported average volume of about 1330 cubic centimeters.
Chimpanzees are known for possessing a great amount of muscle strength, especially in their arms. However, compared to humans the amount of strength reported in media and popular science is greatly exaggerated with numbers of four to eight times the muscle strength of a human. These numbers stem from two studies in 1923 and 1926 by a biologist named John Bauman. These studies were refuted in 1943 and an adult male chimp was found to pull about the same weight as an adult man. Corrected for their smaller body sizes, chimpanzees were found to be stronger than humans but not anywhere near four to eight times. In the 1960s, these tests were repeated and chimpanzees were found to have twice the strength of a human when it came to pulling weights. The reason for the higher strength seen in chimpanzees compared to humans are thought to come from longer skeletal muscle fibers that can generate twice the work output over a wider range of motion compared to skeletal muscle fibers in humans.
It is suspected that human observers can influence chimpanzee behavior. It is suggested that drones, camera traps and remote microphones should be used rather than human observers.
Chimpanzees live in large multi-male and multi-female social groups, which are called communities. Within a community, the position of an individual and the influence the individual has on others dictates a definite social hierarchy. Chimpanzees live in a leaner hierarchy wherein more than one individual may be dominant enough to dominate other members of lower rank. Typically, a dominant male is referred to as the alpha male. The alpha male is the highest-ranking male that controls the group and maintains order during disputes. In chimpanzee society, the ‘dominant male’ sometimes is not the largest or strongest male but rather the most manipulative and political male that can influence the goings on within a group. Male chimpanzees typically attain dominance by cultivating allies who will support that individual during future ambitions for power. The alpha male regularly displays by puffing his normally slim coat up to increase view size and charge to seem as threatening and as powerful as possible; this behavior serves to intimidate other members and thereby maintain power and authority, and it may be fundamental to the alpha male’s holding on to his status. Lower-ranking chimpanzees will show respect by submissively gesturing in body language or reaching out their hands while grunting. Female chimpanzees will show deference to the alpha male by presenting their hindquarters.
Female chimpanzees also have a hierarchy, which is influenced by the position of a female individual within a group. In some chimpanzee communities, the young females may inherit high status from a high-ranking mother. Dominant females will also ally to dominate lower-ranking females: whereas males mainly seek dominant status for its associated mating privileges and sometimes violent domination of subordinates, females seek dominant status to acquire resources such as food, as high-ranking females often have first access to them. Both genders acquire dominant status to improve social standing within a group.
Community female acceptance is necessary for alpha male status; females must ensure that their group visits places that supply them with enough food. A group of dominant females will sometimes oust an alpha male which is not to their preference and back another male, in whom they see potential for leading the group as a successful alpha male.
Chimpanzees make tools and use them to acquire foods and for social displays; they have sophisticated hunting strategies requiring cooperation, influence and rank; they are status conscious, manipulative and capable of deception; they can learn to use symbols and understand aspects of human language including some relational syntax, concepts of number and numerical sequence; and they are capable of spontaneous planning for a future state or event.
In October 1960, Jane Goodall observed the use of tools among chimpanzees. Recent research indicates that chimpanzees’ use of stone tools dates back at least 4,300 years (about 2,300 BC). One example of chimpanzee tool usage behavior includes the use of a large stick as a tool to dig into termite mounds, and the subsequent use of a small stick altered into a tool that is used to “fish” the termites out of the mound. Chimpanzees are also known to use smaller stones as hammers and a large one as an anvil in order to break open nuts.
In the 1970s, reports of chimpanzees using rocks or sticks as weapons were anecdotal and controversial. However, a 2007 study claimed to reveal the use of spears, which common chimpanzees in Senegal sharpen with their teeth and use to stab and pry Senegal bushbabies out of small holes in trees.
Prior to the discovery of tool use in chimps, humans were believed to be the only speciesto make and use tools; however, several other tool-using species are now known.
Nest-building, sometimes considered to be a form of tool use, is seen when chimpanzees construct arboreal night nests by lacing together branches from one or more trees to build a safe, comfortable place to sleep; infants learn this process by watching their mothers. The nest provides a sort of mattress, which is supported by strong branches for a foundation, and then lined with softer leaves and twigs; the minimum diameter is 16 feet (5 meters) and may be located at a height of 10 to 150 feet (3 to 45 meters). Both day and night nests are built, and may be located in groups. A study in 2014 found that the Muhimbi tree is favored for nest building by chimpanzees in Uganda due to its physical properties, such as bending strength, inter-node distance, and leaf surface area.
Studies have shown chimpanzees engage in apparently altruistic behaviour within groups. Some researchers have suggested that chimpanzees are indifferent to the welfare of unrelated group members, but a more recent study of wild chimpanzees found that both male and female adults would adopt orphaned young of their group. Also, different groups sometimes share food, form coalitions, and cooperate in hunting and border patrolling. Chimpanzees have adopted young that come from unrelated groups. Male chimps have been shown to take care of abandoned infant chimps of an unrelated group, though in most cases they would kill the infant.
According to a literature summary by James W. Harrod, evidence for chimpanzee emotivity includes display of mourning; “incipient romantic love”; rain dances; appreciation of natural beauty (such as a sunset over a lake); curiosity and respect towards other wildlife (such as the python, which is neither a threat nor a food source to chimpanzees); altruism toward other species (such as feeding turtles); and animism, or “pretend play”, when chimps cradle and groom rocks or sticks.
Chimps communicate in a manner that is similar to that of human nonverbal communication, using vocalizations, hand gestures, and facial expressions. There is even some evidence that they can recreate human speech. Research into the chimpanzee brain has revealed that when chimpanzees communicate, an area in the brain is activated which is in the same position as the language center called Broca’s area in human brains.
There is some debate as to whether chimpanzees have the ability to express hierarchical ideas in language. Studies have found that chimps are capable of learning a limited set of sign language symbols, which they can use to communicate with human trainers. However, it is clear that there are distinct limits to the complexity of knowledge structures with which chimps are capable of dealing. The sentences that they can express are limited to specific simple noun-verb sequences, and they do not seem capable of the extent of thought complexity characteristic of humans.
Adult common chimpanzees, particularly males, can be very aggressive. They are highly territorial and are known to kill other chimps. Chimpanzees also engage in targeted hunting of lower-order primates, such as the red colobus and bush babies, and use the meat from these kills as a “social tool” within their community.
In February 2013, a study found that chimpanzees solve puzzles for entertainment.
Chimps, as well as other apes, had also been purported to have been known to ancient writers, but mainly as myths and legends on the edge of European and Near Eastern societal consciousness. Apes are mentioned variously by Aristotle. The diary of Portuguese explorer Duarte Pacheco Pereira (1506), preserved in the Portuguese National Archive (Torre do Tombo), is probably the first written document to acknowledge that chimpanzees built their own rudimentary tools. The first of these early transcontinental chimpanzees came from Angola and were presented as a gift to Frederick Henry, Prince of Orange in 1640, and were followed by a few of its brethren over the next several years. Scientists described these first chimpanzees as “pygmies”, and noted the animals’ distinct similarities to humans. The next two decades, a number of the creatures were imported into Europe, mainly acquired by various zoological gardens as entertainment for visitors.
Darwin’s theory of natural selection (published in 1859) spurred scientific interest in chimpanzees, as in much of life science, leading eventually to numerous studies of the animals in the wild and captivity. The observers of chimpanzees at the time were mainly interested in behaviour as it related to that of humans. This was less strictly and disinterestedly scientific than it might sound, with much attention being focused on whether or not the animals had traits that could be considered ‘good’; the intelligence of chimpanzees was often significantly exaggerated, as immortalized in Hugo Rheinhold’s Affe mit Schädel (“Ape with Skull”). By the end of the 19th century, chimpanzees remained very much a mystery to humans, with very little factual scientific information available.
In the 20th century, a new age of scientific research into chimpanzee behaviour began. Before 1960, almost nothing was known about chimpanzee behaviour in their natural habitats. In July of that year, Jane Goodall set out to Tanzania’s Gombe forest to live among the chimpanzees, where she primarily studied the members of the Kasakela chimpanzee community. Her discovery that chimpanzees made and used tools was groundbreaking, as humans were previously believed to be the only species to do so. The most progressive early studies on chimpanzees were spearheaded primarily by Wolfgang Köhlerand Robert Yerkes, both of whom were renowned psychologists. Both men and their colleagues established laboratory studies of chimpanzees focused specifically on learning about the intellectual abilities of chimpanzees, particularly problem-solving. This typically involved basic, practical tests on laboratory chimpanzees, which required a fairly high intellectual capacity (such as how to solve the problem of acquiring an out-of-reach banana). Notably, Yerkes also made extensive observations of chimpanzees in the wild which added tremendously to the scientific understanding of chimpanzees and their behaviour. Yerkes studied chimpanzees until World War II, while Köhler concluded five years of study and published his famous Mentality of Apes in 1925 (which is coincidentally when Yerkes began his analyses), eventually concluding, “chimpanzees manifest intelligent behaviour of the general kind familiar in human beings … a type of behaviour which counts as specifically human”.
Chimpanzees have been commonly stereotyped in popular culture, where they are most often cast in standardized roles as childlike companions, sidekicks or clowns. They are especially suited for the latter role on account of their prominent facial features, long limbs and fast movements, which humans often find amusing. Accordingly, entertainment acts featuring chimpanzees dressed up as humans have been traditional staples of circuses and stage shows.
In the age of television, a new genre of chimp act emerged in the United States: series whose cast consisted entirely of chimpanzees dressed as humans and “speaking” lines dubbed by human actors. These shows, examples of which include Lancelot Link, Secret Chimp in the 1970s or The Chimp Channel in the 1990s, relied on the novelty of their ape cast to make their timeworn, low comedy gags funny. Their chimpanzee “actors” were as interchangeable as the apes in a circus act, being amusing as chimpanzees and not as individuals. Animal rights groups have urged a stop to this practice, considering it animal abuse.
When chimpanzees appear in other TV shows, they generally do so as comic relief sidekicksto humans. In that role, for instance, J. Fred Muggs appeared with Today Show host Dave Garroway in the 1950s, Judy on Daktari in the 1960s and Darwin on The Wild Thornberrys in the 1990s. In contrast to the fictional depictions of other animals, such as dogs (as in Lassie), dolphins (Flipper), horses (The Black Stallion) or even other great apes (King Kong), chimpanzee characters and actions are rarely relevant to the plot.
The rare depictions of chimpanzees as individuals rather than stock characters, and as central rather than incidental to the plot are generally found in works of science fiction. Robert A. Heinlein’s short story “Jerry Was a Man” (1947) centers on a genetically enhanced chimpanzee suing for better treatment. The 1972 film Conquest of the Planet of the Apes, the third sequel of Planet of the Apes, portrays a futuristic revolt of enslaved apes led by the only talking chimpanzee, Caesar, against their human masters.