All rainforest mammals feed their young with milk from mammary glands and this is why their (and our) class is named mammalia, the mammals. Mammals are also the only group with hair. They are endotherms, which means they can maintain a constant body temperature. This is unlike the reptiles, which are ectotherms and must warm themselves periodically using the sun’s energy. Rainforest mammals can vary in size from small mammals like the mouse opossums to large elephants I will mention below.
All three species of elephants can be found in rainforests and even the large ‘savannah’ African elephants frequent rainforest habitat. The African elephants (Loxodonta africana) are the largest of the living elephant species. They have forward pointing tusks they use to dig in the earth or for jousting between males.
African forest elephants (Loxodonta cyclotis) are a fairly recently discovered species. They were previously thought to be a subspecies of the large African elephants. Forests elephants are the smallest elephant and have more rounded ears. They also have a hairier trunk than their large African cousins and their tusks point downwards thought to allow easier movement between the trees.
Asian elephants (Elephas maximus) have smaller ears and tusks than African elephants. Some have been successfully trained and are used in industries like timber extraction. These elephants haven’t been domesticated, as is often mentioned, as elephants are captured from the wild and trained instead of being bred and raised in captivity like a domestic dog or cat.
One of the favorite sights for tourists, monkeys can be very abundant in rainforest areas. Some species like the Amazon squirrel monkeys (Saimiri spp.) often follow groups of tourists through the forest and throw small twigs onto rainforest guests showing their inquisitive nature. Some monkeys have distinct calls specific to courtship, territorial behavior and alarm. Even with this, some monkeys can distinguish to companions if a threat is coming from above or below so the troop knows where to run. Monkeys are very intelligent, although not generally as intelligent as the apes below, and are known to use tools. Some cultures of capuchin monkeys (Cebinae subfamily) for example are known to use anvils and large stones to crack open nuts. This behavior was first recorded by Alexander von Humboldt, an Amazon Rainforest explorer.
Monkeys can be split into two distinct groups: New World monkeys and Old World monkeys, which can often be told apart by nose shape. Most monkeys are very adapted to life in the trees with excellent vision, hand / eye coordination and intelligence. To read more about monkeys of the Amazon, you can read the article on monkeys in the Amazon Rainforest.
Apes are our closest living relatives. We are more closely related to chimpanzees than chimpanzees are to gorillas (photo above). Apes are found in forests on the middle belt of Africa, south east Asia, and of course the human ape has colonized most land masses on Earth. Within the apes, you have the lesser apes (gibbons) and the great apes (orangutans, chimpanzees, gorillas and us). The apes appear to have a very high intelligence and many use tools such as sticks to eat termites, rocks to crack nuts, pneumatic drills to break up pavement, or computers for a range of activities. OK non-human apes don’t use pneumatic drills and only a few use computers, and only then when coerced by a human. There are, however, many other animals now known to use tools like various monkeys and birds. Apes have a shortened spine and broad pelvis which allows for a more upright stance. They also have a wide chest and shoulder blades giving them a wide range of movement and have a flattened face. Gibbons have a ball and socket joint in their wrists allowing for exceptionally fast movement as they swing through the trees.
The photo above shows the eastern gorilla (Gorilla beringei) that lives in central and eastern Africa. They have quite a diverse diet eating fruits, leaves, stems, soft bark, roots and fungus. They are critically endangered.
Armed with retractable claws and acute senses, cats are an adept predator and regarded as the most specialized mammalian carnivore. Large rainforest cats include the pumas (Puma concolor) and jaguars (Panthera onca) in the Amazon Rainforest; the tigers (Panthera tigris) in the Asian and Indonesian rainforests, and the leopards (Panthera pardus) in African, Indonesian and Asian rainforests.
One of the main threats to cats in the wild is hunting followed closely by habitat loss. The pictured species (Panthera tigris) lives in a range of habitats in south and east Asia. Tigers are the largest cat species. All subspecies are regarded as endangered and three species have become extinct since the 1950s. Being such a large and proficient hunter, tigers will catch any manageable animal, including humans on occasion if their natural prey is absent. Tigers do seem to have a preference for wild pigs and deer, and will also feed on carrion.
The pictured sub species is a Bengal tiger (Panthera tigris tigris), which have a fragmented distribution from India through southern Asia to Indonesia.
Here’s an animal you may be less familiar with than the others on this page. This is a tree kangaroo (Dendrolagus spp.). Tree kangaroos live in north eastern Australia and the Island of New Guinea in tropical rainforest habitat. Unlike their kangaroo relatives, they are not very good at moving around on the ground instead preferring life in the trees.
One of the most fascinating things about evolution is the existence of unrelated species that occupy identical habitats and climatic conditions. These animals have been molded by natural selection to sometimes appear similar in appearance and behavior. For example, marsupials and placental mammals are often used to exemplify convergence. This means that in places where placental mammals are absent, marsupials have taken up similar roles. In North America, northern Europe and northern Asia, wolves are well known mammals prowling the forests. Wolves were absent in Australia and Tasmania, and instead lived the Tasmanian tigers that went extinct in the mid 1900s. There are no monkeys in the Australasian rainforests and instead live the tree kangaroos, which have similar feeding and ecological requirements. Convergence can get even stranger. New Zealand is very odd in terms of evolution as it lacks mammals, aside from a couple of bats, and here birds (usually flightless as there are no natural predators) have taken over the mammal roles. Birds didn’t seem to exactly match the requirements of mice, however. This left what is known as an ecological niche open. Guess what filled the role? A large grasshopper called a weta.
Rodents account for 40% of all mammal species and are very adaptable animals. The characteristic feature of rodents is their unusually large incisors meaning they can do the gnawing rodents are known for. The largest species is pictured above in the Tambopata National Reserve, Peru, the large cabypara (Hydrochoerus hydrochaeris). Capybara have semi-webbed toes meaning they can swim well. There is another South American rodent you may be familiar with, the guinea pig. This is one of South America’s only domesticated animals along with the llama. Guinea pigs were bred as food in the Andes and are frequently eaten in Peru, Ecuador and Colombia as a dish known as cuy.