The Mammals of Costa Rica
Mammals developed from reptiles in the late Triassic Period, some 240 million years ago. Here are some important features that distinguish them: Mammals have advanced brains that benefit them in many ways. Hair on their bodies insulates from the cold. Finally, they do not lay eggs, but bear live young (this way, they can stay mobile during pregnancy instead of having to guard eggs). And the production of milk provides an ever available source of food for the offspring.
Of around 4800 mammal species worldwide, 200 can be found in Costa Rica.
Spotting mammals requires similar attention as spotting birds. Early in the morning is a good time (as nocturnal animals make their way to sleep) and zones around water bear a better chance of being frequented by mammals. As with most animals, try to remain quiet as you walk along: if they won’t hear you, you might hear them!
Of the five sloth species occurring in Costa Rica, there are two main families of sloths: two-toed and three-toed sloths. As is well-known of them, they are very slow movers, that spend most of their lives on trees, where they feed on leaves. Because their diet consists of this poor nutrition, their metabolism is so low that it calls for their laziness and low body temperature. The best call to find sloths is to look out for the distinctive Cecropias (called "guarumo" in Costa Rica) or other large-leaved trees: this is where they usually “hang out” (upside down). Sloths switch trees every 2-3 days.
After giving birth to (mostly one single) young, sloth mothers carry their offspring around for four months. After one year, mother and child slowly part way and the young have to find their own tree (it actually takes quite some inventiveness for the mother to leave the child behind due to their slothfulness …).
For reasons that no one really understands sloths take the risk to climb down their tree in order to defecate and urinate every once a week. This behaviour is hard to understand, as there is no obvious need to do so. Every time sloths spend this half hour to go about their “business” they are defenceless and in extreme danger of predators.
cecropia tree (guarumo): where sloths hang out
No Costa Rican holiday would be complete without encountering these close human relatives. Even hundred years before Darwin’s theory, Carl Linnaeus of Sweden classed people in the same category as monkeys. What you will find in Costa Rica belong to the class of “Cebidae”, i.e. New World Monkeys. Typical for this order are unfurred faces with flat noses and long limbs and (prehensile) tails to climb in trees.
There are 4 monkey species in Costa Rica: Howler Monkeys, Spider Monkeys, Squirrel (Titi) Monkeys and White-Faced (Capuchin) Monkeys. They are important seed dispersers as they feed on a variety of fruit. Note that all monkey species are considered endangered – the squirrel monkey even highly so.
Howler Monkeys are the largest monkey species, growing up to 1m and weighing around 5 kilograms. Their habitats are lowland wet evergreen forests. Howler monkeys got their names due to the deep rumbling growls they make in the early mornings to mark their presence and thereby, their territory. In some places (Tortuguero, Corcovado) this will be your wake-up call. Their noise carries for up to five kilometres and makes the loudest sound in the jungle. Despite of these sounds, howlers can move extremely quietly and slow: they rest 80% of the day. Often they might pass the canopy right over you without being noticed!
Spider Monkeys can use their tails like a fifth hand with which they can support their entire body weight. Spider monkeys rarely leave their tree habitats, where they feed on leaves, nuts and fruit. They are known to communicate by gestures: by approach of a human they might climb to the end of a branch and shake it heartily to scare the intruder away. If this does not work, they can throw heavy branches at the unwanted guest.
Squirrel Monkey (esp: titi) is a tiny monkey (ca. 0.6 kg), best found in and around Manuel Antonio National Park. Their habitat are Pacific wet forests, where they feed on insects and small plants. Due to the reduction of lowland forest on the Pacific side “titi” monkeys are endangered. Squirrel monkeys primarily eat fruit and the occasional insect. Interestingly these fast moving monkeys do not use their tails for climbing, but as a balancing pole (similar to cats).
White-Faced (Capuchin) Monkey is the species you are most likely to encounter closely in Costa Rica. They occur on the Caribbean slope’s wet forests as well as the Pacific side’s drier forest habitats. Capuchins are approx. 50 cm high and eat everything from flowers, fruit, bird-eggs, insects to the sandwich you brought to the beach. Their troop size is between 2 to 20, usually grouped around a single adult. Watch out when meeting these overactive primates: they are known to snatch anything edible or shining and are sometimes in an aggressive mood to defend their territory.
Sadly, Capuchin monkeys seem to have undergone a recent rise in pet trade. We condemn this kind trade. Do not force any tropical pet to an imprisoned life!
These felines are clearly the kings of the local jungle. But they are very shy and avoid humans, so that your chance of actually spotting one is very slim. The highest concentration of jaguars is in Corcovado and La Amistad National Parks, where they have enough territory to hunt. Jaguars – known in Costa Rica as El Tigre – are more common, although it is unlikely to be spotted. Jaguars are the largest cats in the new world and can reach lengths of 2 metres with a body height of one metre and a weight of over 100 kg. They hunt mostly at night, as they have excellent vision due to their big eyes. Their prey consists of 87 species, including birds, small peccaries and iguanas up to sloths, monkeys and caimans! They are solitary stalk-and-ambush predators that hunt in territories between 30-40 square kilometres.
Jaguars are endangered and have been eliminated from almost all areas of Costa Rica – mostly because of deforestation. Because jaguars need huge hunting grounds, the installation of biological corridors is paramount. Jaguars are known to live in the protected areas of Corcovado, Santa Rosa and Tortuguero.
The jaguar is defined as a so-called “umbrella species”: they require such a broad territory that whenever they are protected, a number of other species will be directly protected as well. For this reason they are often the focus of preservation efforts; not because they are the kings of the jungle, but because the large area needed for their protection will automatically provide the possibility of a healthy ecosystem.
Ocelots are mid-sized felines, roughly the size of dogs (1 metre length and 10-15 kg weight). Belonging to the Leopardus gene, they can be found all over South and Central America. Ocelots are night-active and hunt on large territories of 18 square kilometres. Their prey consists of reptiles and amphibians and small mammals. In Costa Rica they can be found in the rainforests of Corcovado, Santa Rosa, Monteverde and in the Los Santos Area – though they are rare to spot.
Coatis are tropical racoons of a reddish brown with dark faces and long tails. These social animals are day-active and not generally known to be shy. Their main nutrition consists of small vertebrates such as mice and lizards, as well as fruit and insects. If fed by humans they can become quite tame. You might actually spot bands of a dozen animals in the Area of Arenal, where they often appear at roadsides. You will recognise them by their long muzzles and their bushy tails (of a brownish fur).
Racoons (average size of 40 cm) can easily be recognised by their distinctive “bandit mask” – the black fur around their eyes. The most common racoon is the Northern Racoon, an animal which is active mostly at night. Racoons are omnivorous and feed on fruit and all sorts of animals they can put into their mouth. Despite of their agility in using their hands, the legend that they wash their food before eating is not true (the act of dipping scraps in water is rather for wetting the food).
Tapirs belong to the order of Perissodactyla: hoofed animals with an odd number of toes on each foot (like rhinos and horses). One recognises their kinship with horses by their snouts. Baird’s Tapirs are ca. 2 metres long and can weigh up to 300 kg. Such, they have the honour of being Central America’s largest native mammal. They are herbivores who feed on fruit, grass, leaves and twigs. Tapirs reach an age of 25-30 years and are solitary animals.
As tapirs like to be close to water and are good swimmers, they are often spotted close to a creek or wallow. They can actually sink to the bottom of a riverbed and walk along it to feed!
While the tapir used to be native to many places in Costa Rica, it once was very close to extinction. Many grass swamps, forested hillsides and rainforests have disappeared, thereby dangerously reducing their habitat. Today, tapirs are recovering in the National Parks of Corcovado and Tenorio. But the establishment of Biological Corridors is paramount to let this specie (listed as endangered/vulnerable) recover further. In Costa Rica, a biological corridor is being established between Corcovado National Park and the Los Santos Reserve to extend its habitat range. This is an important and visionary contribution to wildlife protection in the American tropics. (The Baird’s tapir project, starting in 1994, was actually the first protection programme for this mammal in the world).
Tapirs have become an important symbol of preservation because they thrive in primary forests.
A tapir mother is actually known to feel at home around the Sirena Ranger Station in Corcovado; here she is often spotted, taking a nap in the shadow of a tree during daytime.
Peccaries – as pigs, giraffes, bison and cattle - belong to the order of Artiodactyla, that is hoofed animals with an even number of toes on their feet. In fact, they do look similar to pigs, having coarse hair, small ears and tails and tusk-like teeth. With their long snouts, they dig the earth, feeding on fallen fruit, leaves and grass. There are two peccary species in Costa Rica, which live mostly in groups (the White-Lipped Peccaries being more sociable than the Collared Peccaries).
Despite their reputation of being dangerously aggressive, peccaries are rarely a threat. Although they are of large size and could do severe damage with their tusks they rarely attack. If you encounter them, try to stay quiet and leave them alone (their vision is not good).
Armadillos can easily be recognised by the armour plating on their backs. The armour consists of plates of dermal bones that are covered with small epidermal scales with a horn covering. These solitary animals are around 50 cm in length and not spotted very often because they are active mainly at night. Their main nutrition are ants, termites and other insects, which they access by digging into the ground with their sharp claws.
Famous for their night activity and sonar system, bats have a strong fascination on humans. Bats come in various sizes between 5-80 cm and weigh from 5g to 200g. During daytime bats can be found in their roosts (mostly caves, tree cavities of just a shady part of a tree). At night bats are out to eat: mostly they feed on insects which they catch directly with their mouths or use their wings as spoons. Some species are frugivorous and the “Common Vampire Bat” actually does feed on: blood! They push their sharp teeth into the necks of sleeping animals, remove a tiny piece of skin and lap the dripping blood. Because this makes very nutritive food they only need about half an ounce per day.
The bats that feed on nectar are important pollinators (like bees and birds). Flowers that depend on bats for pollination are mostly white and open at night to be recognised more easily.
At night bats navigate with a sonar system of echolocation: they broadcast ultrasonic sounds and scan the environment by the returning echo within split seconds.
Bats are some of the most varied mammals in the world. There are over 950 worldwide. They are clearly leading in Costa Rica: there are 200 odd mammals here, and 105 of them are bats!
Opossums, with their pointed noses and hairless tails remind of rats, but are not of the same family. They are best seen at night, when they are out to feed. Known as omnivorous animals, opossums will eat almost anything that crosses their way. Because carrion is among their preferred meals, they often end up as roadkill themselves, while feeding on such.
Opossums are so-called “marsupial breeders”: they give birth about 15 days after mating. The children are almost still embryos when they climb out but remain in the mother’s pouch, where they feed for another 2 months. This is the same breeding system we know from kangaroos.
Opossums have particular immune systems that renders them invulnerable to a variety of snakebites, such as rattlesnakes and the vicious pit vipers.
Paca and Agouti are rodents and hence marked by their efficient large incisor teeth, with which they are able to cut and slice an abundance of materials. They are vegetarians that feed on fruit, seeds and nuts and the occasional insect to boost their protein level. Ecologically they seem to be relevant for the survival of jaguars, as they make an important part of their prey.
Deer are large mammals, found in many regions of the planet. They are grazers and cud-chewers who regurgitate their meals and chew it again to digest it. Although it surprises many travelers, deer are quite common in Costa Rica and are not seldomly spotted on the edge of a wood.