Unity in the Wild: A Troop of Chimpanzees

Chimpanzees, scientifically known as Pan troglodytes, are our closest living relatives in the animal kingdom. They offer a captivating glimpse into the complexities of social behaviour, cognitive prowess, and evolutionary history. From the lush rainforests of Africa to the confines of research sanctuaries, these remarkable primates continue to astound scientists and enthusiasts with their traits and behaviours.

Exploring the Unique Traits and Worldwide Habitats of Our Closest Relatives

Chimpanzees possess distinctive physical traits that define their species. They usually have long arms hanging up to the knee, each arm having an opposable thumb that adds to their grasp of tools. Chimpanzees are terrestrial, although they spend most of their day in trees, and at night, they sleep in nests made from vegetation. This species walks “on all fours,” although individuals of this species can walk with two legs for over one kilometre. Young ones can swing from one branch to another.

A Chimpanzee strolls on foot: Captured during a visit to Dehiwela Zoological Garden on 30th of June 2024

Chimpanzees lack hair on the face, skin, ears, palms, and soles of the feet, though the rest of the body is covered in hair, usually brown to black. In rare cases, albino chimpanzees with white fur and pink skin may exist due to genetic mutations affecting pigmentation. Young chimpanzees often have pink or white faces that darken as they mature. With age, chimpanzees may experience balding on their foreheads, and their fur can gradually turn grey. Adult chimpanzees exhibit a wide range of sizes, standing between approximately 3.2 and 5 feet tall. Males generally weigh between 40 and 60 kg, while females typically range from 32 to 47 kg. These physical characteristics contribute to their remarkable adaptability and survival strategies in their natural habitats, like tropical forests and woody savannas.

Generations Together: An adult and young chimpanzee in harmony

There are definite chimpanzee subpopulations differentiated by physical appearance and their distribution over different geographical areas. They include:

  • Central chimpanzees (Pan troglodytes troglodytes) are indigenous to Cameroon, the Central African Republic, Equatorial Guinea, Gabon, and the Congo Basin. The current wild population is about 115,000 individuals.
  • Western chimpanzees (Pan troglodytes verus) are endemic to the Ivory Coast, Guinea, Liberia, Mali, Sierra Leone, Guinea-Bissau, Senegal, and Ghana. The population consists of between 21,300 and 55,600 individuals.
  • Nigeria-Cameroon chimpanzees (Pan troglodytes ellioti) are found in the forests of Nigeria and Cameroon. There are less than 6,500 individuals left.
  • Eastern chimpanzees (Pan troglodytes schweinfurthii) inhabit the Central African Republic, South Sudan, the Democratic Republic of the Congo, Uganda, Rwanda, Tanzania, and Zambia. The population is estimated to be between 76,400 and 119,600 individuals.
Geographic range of chimpanzees

Unlocking the Intricacies of Chimpanzee Life

Chimpanzees have complex and dynamic social systems that integrate them into closely bonded groups, much like extended families. Such groups, often referred to as troops, may consist of a few individuals to over a hundred members. Usually, an alpha male leads the group and is responsible for keeping order and resolving any controversies that arise. There appears to be a hierarchy among female chimpanzees as well, with an alpha female typically leading the group. However, an alpha male usually surpasses an alpha female in rank. Unlike males, who often gain dominance through aggression and violence, alpha females tend to achieve their status through relationships and personality. Generally, males remain in their natal community, while females transfer to another community upon reaching adulthood. Communication among chimpanzees is well-comprised and varied, with vocalizations, facial expressions, and expressive gestures of emotions, warnings, or intentions. They have specific calls at different occurrences. They use various calls to warn their group of predators’ presence or to inform them about the discovery of foods. Facial expressions and body language are also used, such as embracing or patting, to express emotions and intentions. They express a broad spectrum of emotions, including joy, sadness, and anger, and also feel empathy. Chimpanzees console one another in times of distress and also show signs of mourning whenever a member dies. Grooming is another activity chimpanzees do to reinforce social bonds, and it helps in the cohesion of the group. The chimps groom not only for their physical health but also as part of their social life since it helps them bond as they get ticks and dirt off each other’s bodies.

Chimpanzees are omnivores, and their diet ranges from fruits, seeds, flowers, and insects to meat once in a while. They are known to engage in coordinated group hunts, targeting smaller mammals such as colobus monkeys and young antelopes. In addition to their varied plant-based diet, chimpanzees feed on a variety of other foods, with around 80 items documented by scientists as seeds, fruits, leaves, bark, honey, flowers, and insects.

Female chimpanzees invest heavily in their offspring, carrying them for up to five years and sometimes nursing them for several more. During this period, mothers teach their young ones the essential survival skills of foraging and tool use, establishing a close bond crucial for the infant’s development and social integration. Chimpanzees breed year-round. The gestation period is 202-261 days, and females give birth to single young, rarely twins; there are interbirth intervals of 5–6 years, although three offspring on average will survive. The infant chimp will stick to the belly of the mother for the first 6 months before riding on the mother’s back. Weaning time ranges between 3.5 and 4.5 years; however, it may depend on the mother for as long as up to 10 years since it learns crucial skills that are necessary for survival. Chimpanzees reproduce at the age of 7 years, but females generally do not give birth until age 13–14.

Clinging to Care: A Baby Chimpanzee on its mother’s back

Chimpanzees live as long as 40–50 years in the wild, while many in captivity often live beyond the age of 60. Due to the fact that they live so long, they naturally have extended learning and social integration time, letting the elders transfer knowledge and skills down to the juniors. For example, Cheetah the Chimpanzee, an animal actor from Tarzan films of the 1930s and ’40s, is said to have lived to about the age of 80 years.

Ingenious Minds: The Tool Use and Intelligence of Chimpanzees

Chimpanzees are intelligent and, on the other hand, very innovative in using tools to aid in getting food. The intelligence and creativity in the problem-solving of chimpanzees are incredible. It has been observed that these chimpanzees use tools adequately in most of their daily survival activities. A common example is how they remove insects from the ground with sticks, and also nuts that are cracked open with rocks. It was first recorded by Dr. Jane Goodall and overturned the belief that only humans can use tools. Water-deprived chimpanzees chew leaves into soft, spongy pulp so that leaves can be used to absorb rainwater from tree holes.

A Crafty Forager: A Chimpanzee using a twig to extract termites

Chimpanzees indicate a very high order of cognitive capabilities, including problem-solving, memory, and planning. Chimpanzees learn socially by observation and imitation. Chimpanzees were trained with great success in captivity to learn sign language and other symbols to communicate with humans. Experiments have revealed quite vividly that the most striking cognitive abilities were possessed by chimpanzees. They have been shown to remember the locations of food sources over time, solve complex puzzles to get a particular reward, and even show delayed gratification projects done earlier, which is an advanced cognitive process just like in human beings. Those kinds of abilities provide evidence regarding the depth of intelligence and adaptative capabilities in different situations. Chimpanzees ingest medicinal plants with antibacterial and anti-inflammatory properties in cases of sickness or injury. The behaviour presents very strong evidence that our close relatives practice self-medication. In a surprising observation, researchers have documented well-digging behaviour among a group of chimpanzees in Uganda. This behaviour was instigated by an immigrant female in the group. The chimpanzees occupy a rainforest habitat where water is usually plentiful, so the finding came as a surprise. With their newly acquired well-digging techniques, chimpanzees have developed an adaptive skill that enhances their survival during droughts and other environmental changes.

Our Primate Kin: The Close Relationship Between Humans and Chimpanzees

Chimpanzees and humans share a common ancestor. From this ancestral population, one lineage evolved into anatomically modern chimps, while another gave rise to early human species, culminating in Homo sapiens. Chimpanzees are our closest genetic relatives, sharing about 98.6 percent of our DNA. Comparative studies of the human and chimpanzee genomes have pinpointed specific genetic changes, some of which may explain unique human traits. The genetic insights are crucial for understanding the evolutionary pathways that shape primate behaviour and cognition.

Beyond genetic studies, detailed observations of chimpanzee behaviour reveal fascinating parallels with humans. Like us, chimpanzees spend much of their childhood and adolescence playing. They exhibit a sense of fairness and can distinguish between proper and improper actions. Chimpanzees experience a wide range of emotions, such as happiness, sorrow, fear, and compassion, which they express through body language, facial expressions, gestures, and vocalizations.

These behavioural similarities highlight our shared evolutionary history and offer a window into how complex behaviours and cognitive development evolved in both species. They underscore what makes us uniquely human while emphasizing our deep biological connection with our closest living relatives.

Facing Peril: The Threats Endangering Chimpanzees

Chimpanzees, our closest living relatives in the animal kingdom, face a myriad of threats that jeopardize their survival. Unfortunately, all chimpanzees are listed as endangered by the International Union for the Conservation of Nature (IUCN). These challenges highlight the urgent need for concerted conservation efforts to safeguard these intelligent and iconic primates.

  • Habitat Loss and Fragmentation: Deforestation, agricultural expansion, and human infrastructure development have significantly reduced chimpanzees’ natural habitat. Their reduced living spaces make it difficult for the chimpanzees to find food, shelter, and potential breeding partners. Due to this fragmentation, the populations are isolated from one another, which keeps their range low, and hence genetic diversity.
  • Poaching and Illegal Wildlife Trade: Despite the legal protections in place, chimpanzees remain threatened due to poaching for bushmeat and the illegal pet trade. Young chimps are oftentimes taken for sale as pets; this usually involves the killing of their mothers and other adults in their group. Bushmeat has always been a primary food source in Central and West Africa, but in recent years poaching has become commercialized to satisfy the appetites of wealthy urban residents.
  • Disease Outbreaks: Chimpanzees are susceptible to more than 140 diseases transmitted from humans. Outbreaks of diseases such as Ebola and respiratory infections have devastated chimpanzee communities in some regions. More rapid transmission from human populations increases their vulnerability, hence creating such a need with respect to mitigating incidents of disease transmission in their habitats.

Saving Our Relatives: Conservation Efforts for Chimpanzees

Chimpanzee conservation puts forward several activities targeting the effective protection of these endangered primates and their habitats. These involve, but are not limited to, habitat protection initiatives, anti-poaching, and educational efforts at the community level. Sanctuaries provide a haven for orphaned and rescued chimpanzees, while international treaties and laws try to act on illegal wildlife trade and habitat destruction. Other conservation activities include population size monitoring and control of chimpanzees through the latest technologies, such as camera traps and drones, to ensure wildlife corridors and the enforcement of sustainable livelihoods efforts that will benefit both chimpanzees and locals. The Wildlife Conservation Society, the Jane Goodall Institute, and the World Wildlife Fund are among other organizations working cooperatively at higher levels with governments, local communities, and researchers to raise awareness and enforce wildlife laws to rehabilitate chimps rescued from illegal trade or captivity.

The events that transpired regarding the ongoing efforts at conservation are very much at the forefront in 2024:

  • Chimp Haven Events: Chimp Haven, the world’s largest sanctuary, hosted a variety of exciting events, including “Chimp Chat” and “Chimpanzee Discovery Day,” to enlighten visitors about life and conversation efforts at a chimpanzee sanctuary.
  • Operation Red: In January 2024, Liberia’s Special Wildlife Investigation Unit carried out “Operation Red,” resulting in the arrest of multiple wildlife traffickers and the rescue of a baby chimpanzee. The operation underscored the ongoing dangers and threats to chimpanzees and highlighted the integral role of conservation organizations in safeguarding their welfare.

World Chimpanzee Day is dedicated to the protection of chimpanzees and their habitats and is celebrated annually on July 14. On this day in 1960, Dr. Jane Goodall started her groundbreaking research into what is now Gombe Stream National Park, Tanzania, for a new insider’s view of chimpanzee life. It is a day to celebrate not just the great contribution chimpanzees make toward biodiversity but, more importantly, what mankind learns from primates; there is an even greater need to spread awareness about their pressing conservation.

In supporting research and conservation, we gain an understanding of the detailed social structures and behaviours of chimpanzees to ensure their survival and appreciation of these intelligent and invaluable members of the primate family. Let this day be one of action toward awareness and action toward protecting chimpanzees and their habitats for generations to come.

Written by:

S.A. Lohini Lenmini,

1st Year Undergraduate,

Biological Science,

Faculty of Science,

University of Colombo.

References:

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