[Additions will be made to this section in the future.]
i) Arthropods: Insects are by far the most numerous arthropods, and, indeed, animals, by a huge margin, both in terms of number of species and in numbers of individuals. Erwin and Scott (1980), in a famous study of insects in a Panamanian rainforest, found so many species of insects in a single canopy tree that Erwin (1982) later estimated that there are 30 million species of insects in the world. This estimate is not accepted by everyone, but it is clear that there are many more species of insects (not to mention other organisms) on earth than we have identified, or even suspected, until recently. The majority of the species which Erwin found – 83% of the beetle species, for instance – are indigenous to a particular tree species, a particular area, and in some cases, perhaps, even to an individual tree. Of 1080 beetle species in four different types of lowland rainforest in Brazil, he determined that only 1% of the species were found in all four. This is perhaps not too unexpected, since the plots were fairly far apart, but even in two plots only 50 meters apart, less than 9% of the species were found in both (Erwin, 1988). This is a remarkable degree of endemism.
a. Butterflies: Butterflies are conspicuous residents of tropical forests and there are many species of them. In Brazil, 800 species have been identified within an area of approximately 3 km2, and probably there are more than 1500. In comparison, in all of eastern North America there are 440 species; in Europe and North Africa, there are 380 species.
b. Ants: In Peru, a single tree was found to contain 43 species of ants, from 26 genera. This is approximately equal to the total ant fauna of the entire British Isles (Wilson, 1988). The common army ant, Eciton burchelli, of the Neotropics has the curious role of keeping populations of other ant species under control. Ants of this species penetrate the forest in columns of 15 meters width and one or two meters depth, and move up to 200 meters per day. As the column passes along the forest floor, it attacks other ant colonies, as well as other insects which it encounters en route. Besides keeping other species of insects in hand (or in mouth) this species is an essential ingredient in the Neotropical rainforest because it provides food for many birds by “flushing” out insects which flee in advance of the ant column. Some of these birds, among them several species of antbirds (Hylophylax naevioides, the spotted antbird; Gymnopithys leucaspis, the bicolored antbird; and Phaenostictus mcleannani, the ocellated antbird), are obligate (i.e., compulsory) army ant followers. Other birds snatch insects wherever they can, but are roused by army ant columns to follow them. Such are the barred forest falcon (Micrastur ruficollis), the plain brown woodcreeper (Dendrocincla fuliginosa) and the bright-rumped attila (Attila spadiceus). Thus these ants are considered keystone species in these forests, as so many species depend upon them for food and population regulation. Moreover, they are indicators of forest fragmentation. When a forest is cut into fragments, they lose their army ant colonies and, in addition, their avian followers. Such birds are the first to disappear from forest fragments, but will reappear when forest is allowed to regenerate around such fragments (Matlock, 2001).
c. Beetles: Erwin (see above) estimated that most of the insect species he found, perhaps 40%, are beetles. This may be an overestimate, yet further surveys of living canopy beetles yielded many new species; 70 species of beetles have been found in the tendrils of canopy lianas alone. New species continue to be found at undiminishing rates in canopy surveys.
d. Termites: All tropical areas are replete with termites. As mentioned above, termites in their great profusion play a role in global warming by their release of methane and CO2. These are social insects and live in large nests – underground, hanging in trees, or in large earthen mounds. They have worker, soldier and queen castes. Termites consume wood, and are able to do so because they have protozoans in their guts which themselves are hosts for symbiotic spirochetes (bacteria) which produce cellulase, an enzyme which can dissociate the cellulose in plant cell walls. Many termite nests are composed of digested wood and fecal material which acts as a glue to hold the nest together. Termites carry litter from the forest floor to their nests, and so the nests contain considerable quantities of nutrients. These nests are frequently abandoned, and form patches of high nutrient content. In this way termites may affect nutrient cycling and soil quality. Many tropical woods are extremely hard (that is, the walls of the woody cells are heavily armored), and some scientists speculate that they have evolved in this way in response to the assaults of termites. Some woods also contain toxic compounds which aid in repelling termites.
i) Fish: Many species of fish inhabit the waterways of tropical rainforests. The Amazon River and its tributaries, because of their size and extent, contain the greatest known diversity of freshwater vertebrates, mainly fish, perhaps 2000 species, of which about 90% are endemic. Some of these we know from the tropical fish trade, while others are known only to local inhabitants, still others are a major food, as well as income, source. Much of the commercial fishing in tropical countries is done in freshwater, rather than marine, environments.
Tropical freshwater ecosystems are closely intertwined with the surrounding forest. Nutrients such as phosphorus and nitrogen normally enter the waterways as rain leaches them from forest soils. They are essential elements for aquatic algae, which provide food for plankton and insects, which are eaten by small fish, which in turn are eaten by larger fish. Changes in land use disrupt this chain by altering the amount of nutrients in the water, and so on up the chain. Surprisingly, fruits and seeds are also extremely important to aquatic systems in some rainforests. There are at least 200 species of fruit and seed-eating fish in the Amazon region, an adaptation unique to this area. Generally, environmental destruction in the Amazon has been the major factor in the decline in fish populations. Removal of forests, even in areas far removed from a fish’s habitat, can have dire consequences.
a. The tambaqui (Colossoma macropomum) is a huge fish which lives in river channels of the Amazon flood plains. A large specimen reaches more than one meter in length, and weighs as much as 25 kilograms. As these are slow-growing animals, they require seven years to attain this size (Salati, et al., 1993). The young are carried into the plains during the rainy season and shelter under “floating meadows” – floating vegetation which forms in sunny patches where the trees do not overhang the water. These fish live on zooplankton, algae and grass seeds when young and as adults seek fruits, nuts and seeds (particularly seeds of the rubber tree) which have fallen into the water. They locate food by scent. At the end of the flood season, the young go into lakes in the floodplain, and the adults migrate to the river channel, where they live on the fat reserves they have accumulated during the flood season. The tambaqui is an important food species, and tasty. This has led to their overexploitation by commercial fishing operations, which set nets across river channels or use gillnets and seines in the lakes to catch juveniles. Now, a fishing boat must travel two or three thousand kilometers to find large tambaqui; the average size of a tambaqui in the market in Manaus, Brazil, is rarely above the legal limit of 55 cm, although an adult tambaqui can be more than one meter in length (Salata, et al., 1993).
ii) Amphibians: Amphibians are in trouble. Everywhere on the globe, amphibians are declining in numbers. In most cases, the cause is probably loss of habitat and unsustainable use. Other factors are pollution and the introduction of competitive or predatory exotic species. In some cases, disease appears to be a culprit (see below, Section G 5e), but the overall picture is little understood for tropical forest species. (For amphibian and reptile declines, see Gibbons, et al., 2000.)
a. Frogs: Frogs are obliged to live near water, since their skins must be kept moist in order for respiration to occur across the epidermis. Most lay bunches of eggs in shallow water; these eggs hatch into tadpoles, which later metamorphose into juvenile frogs. However, many frogs have developed very exotic reproductive mechanisms, and may lay their eggs in foam nests, in holes in trees, in the water-filled cavities of bromeliad leaves; some give birth to live young. [See a link elsewhere on this website for the frogs of Peru.]
i) Poison-dart frogs (Dendrobatidae): Among the most interesting of the tropical frogs are the poison-dart frogs, which produce potent toxins in their skin which can be used for making poison for arrow tips. These frogs are highly-colored, often with brilliant stripes along their backs – red, yellow, blue, green or orange. These frogs are terrestrial, and lay their eggs on land. After the eggs hatch, the female will carry the tadpoles to water, where she feeds them with her own unfertilized eggs – apparently in response to a behavioral cue from the tadpoles!
b. Toads: Toads are terrestrial and have tough, impervious skins, unlike frogs. They are not usually poisonous, but a few, such as the giant marine toad of the Americas, are similar to the poison-dart frogs in that they secrete toxins in their skins.
a. Lizards: There are many types of lizards in tropical forests, where they play a variety of roles, from vegetarian to carnivore.
i) Iguanas: Iguanas are common in neotropical forests and are among the largest reptiles in the Western Hemisphere. When adult, they can attain a length of six feet or more. Although vegetarians, they look ferocious because of their dorsal spines, and can cause serious injury to a predator with a lash of their tails or a swipe of their long claws. They eat fruits and leaves and are found near water.
ii) Tegu lizards: These are fairly large lizards of the Neotropics. They can reach 4½ feet in length. They are carnivorous, eating small animals and eggs. Some are partially aquatic, like the iguanas.>
iii) Geckos: Geckos are ubiquitous creatures of all tropical forests. They live entirely on insects, and are highly territorial. They warn invaders in their space by thumping their dewlaps against the surface to which they are clinging. They also make a surprisingly loud call resembling “GECK-O, GECK-O,” hence their name. Their toes have minute protuberances which act as tiny suction cups, enabling them to cling to vertical surfaces and ceilings. The large Tokay gecko often has beautiful blue and yellow spots on its body, and has a formidable call, which varies from one area to another. One, in southern Thailand, has a call which sounds like “FOOT-BALL, FOOT-BALL,” and begins calling each evening at exactly the same time – 6:20 p.m.
b. Snakes: Snakes, poisonous or not, are very compatible with tropical forest ecosystems and there are many hundreds of species in the tropics. In the whole of California there are 30 species of snakes, while a few square miles of Peruvian rainforest may contain 75. Moreover, tropical snakes are much more diverse in anatomy, life style and habitat than are temperate snakes. Nothing is known of the conservation status of most tropical snakes, but many species of snakes in temperate climates are endangered. As with other animals, the fragmentation and destruction or degradation of habitat is the major factor in their population decline. For some snakes, the introduction of invasive species into their areas has been devastating. The introduction of the mongoose into Caribbean islands decimated snake populations; rats had a similar effect on boa populations in Mauritius. Many snakes are killed for their skins, for food, because they are thought to impinge negatively on human activities, or because of fear; they are also captured for the pet trade. Snakes, because of their diets, compete with other predator species, mainly raptors and carnivorous mammals, in the many habitats in which they live.
i) Constrictors: Constrictors are the largest of snakes and kill their prey by coiling around the prey animal in a way that rapidly interferes with breathing and blood circulation. They are tree-dwelling and eat all kinds of animals – rodents, other reptiles, and birds. Big constrictors can consume remarkably large prey, even some which is more than half their weight. They may use hunting or ambush tactics. The anacondas in the Neotropics, the pythons in Southeast Asia, Africa, and Australia, and the widely-distributed boa constrictors are the best known of these snakes.
Boa constrictors range widely in a variety of habitats, give birth to live young (viviparity), are mainly terrestrial, and everywhere feed only on vertebrates such as iguanas and other lizards, rodents, and, occasionally, birds. They can wait for prey for days by lying coiled in auspicious places, such as near rodent burrows. It is reported that very large constrictors can eat adult humans (a reticulated python in Indonesia, for one; [Greene, 1997]). Madagascar has boas closely-related to South American boa constrictors, although they are relatively small (less than 2 meters long). They are rainforest snakes and live in the vicinity of water. The Calabar burrowing boa of West African forests, unlike other boas, lays eggs, and may use its tail to protect its head from the parents of the baby mice which it seeks for its prey. Some anacondas are aquatic, and may be quite large; the heaviest known snakes belong to this group.
Pythons generally have teeth on their upper jaw just below the snout, lay eggs (oviparity) and, like boas, are found in a variety of habitats, from the arid parts of Australia to tropical rainforests. The green tree python is specialized for living in the tropical rainforest canopy, but more commonly pythons are terrestrial.
ii) Vipers, adders and pitvipers are found throughout the tropics, except Australia, and are characterized by triangular heads. They have extremely diverse modes of life, habitats, and types of prey. Some are oviparous, others are viviparous; some (pitvipers) remain with their young, others do not. These snakes are highly poisonous (some more than others) and include the fer-de-lance and bushmaster of the Neotropics and the green viper of Southeast Asia. Although many vipers live in rainforests, only one, the Eyelash pitviper of Honduras is on the CITES list of endangered species. Vipers are mostly terrestrial, although some are arboreal. Generally they have a fairly sedentary way of life, and ambush their prey. They kill their prey with potent toxins and, like other snakes, can ingest large prey because of their flexible jaws. They typically bite their prey, release it, and find it by following its scent. Its sense of smell is so keen it can discriminate its poisoned victim from other animals.
Pitvipers are distinguished by pits, which sense infrared radiation, above their eyes. Blind vipers can sense a mouse from some distance away because of these organs. It seems that these organs are not primarily for prey detection, but may have some defensive function. Most vipers also have a tail spine which can be vibrated against vegetation to make a noise as a defensive mechanism. (Note that the rattlesnake is a viper.) Tropical specimens, such as the Malayan pitviper, can be quite large, and reach lengths of 1.5 meters.
iii) The elapid snakes include the coral snakes (American), the cobras (Asian), the mambas (African) and other poisonous snakes which have large, immovable fangs in the front of their mouths and often some smaller teeth behind. Their venoms are neurotoxins, which affect the nervous system of the prey. Death of the victim comes by paralysis of the diaphragm muscles, leading to suffocation. Most elapids are oviparous, but a few are viviparous.
The most famous elapids are the cobras, which are middle-sized to large snakes. They have characteristic expanding “hoods” which make them appear fearsome. The famous “spitting” cobras of Asia and Africa have fangs modified to eject venom toward the eyes of a perceived adversary. They eat vertebrates, other snakes and even fish.
iv) Nonpoisonous, nonconstrictor snakes: There are many varieties of innocuous (to humans) snakes, although they are all carnivores. Among these are the small tree snakes, such as the paradise tree snake of Southeast Asia, a small thin green snake which is entirely arboreal.
c. Crocodilians: Crocodiles, alligators and caimans are all warm-weather reptiles, and many types are found in the rivers of tropical rainforests. The caiman is a small alligator of South America, while crocodiles are found in Africa and Asia. They spend most of their time in the water, since their food supply consists of fish, as well as mammals, birds and reptiles which they catch near or in the water. They are egg-laying reptiles and make their nests in river banks.
Reptiles, following the pathway of amphibians, are now undergoing severe population declines all over the globe. The magnitude of this phenomenon is difficult to determine, but it is substantial. Habitat loss is the most likely factor in a great deal of this decline, with the introduction of exotic species (usually predators, but in some cases other reptilian species which compete for space and food), pollution (fertilizers, herbicides and pesticides, and other contaminants), diseases and parasitism, global warming and unsustainable use (for the pet trade, food, skins and biological research) are all implicated (Gibbons, et al., 2000).
iv) Birds: Approximately 2500 species of birds live in tropical forests. In New World rainforests, a single square kilometer may contain several hundred bird species. The great variety of food and habitats available permits birds to specialize in food sources, type of shelter, and nesting sites, so that many species can live in a small area. Thus there are many species of thrushes, for example, each specializing in a different diet without competing with the others. Many birds are frugivores (fruit-eaters); others are insectivores (insect eaters); still others eat nectar. Some eat insects from leaf, twig, and trunk surfaces; still others search in bark for insects; woodpeckers burrow into the wood for their prey. Hummingbirds live almost exclusively on nectar from plants; in doing so many of these nectar-loving birds transfer pollen from one plant to another. Because of the relatively equable climate, tropical forests provide food and shelter all year around, and so birds need not spend most of their time searching for food sources. This frees them for elaborate mating rituals and displays. Birds are extremely important forest denizens, since they provide many services such as pollination and insect control.
a. Selected birds of tropical forests [See also elsewhere on this website for birds of Peru.]
i) Bird of paradise: Birds of paradise, which live only in New Guinea, have been objects of human interest for many years because of their remarkable adaptations for reproduction. Males are brightly-colored and have elaborate, sometimes elongated, tail feathers which they display for the females in complex mating rituals. The male must first find a suitable display area, and may fight with other males for one. Only a few males occupy such a site at any one time. The blue bird of paradise of the highlands of eastern New Guinea is an extremist – he hangs upside down from a branch and sways back and forth, while displaying his bright iridescent blue plumage and long tail feathers. At the same time he makes a loud whirring noise to attract females, which observe his display from the periphery. The blue bird of paradise’s gorgeous feathers have led not only to its survival – by encouraging mating! – but to its decline. The desire for bird plumes for hats in developed countries during the last century and a continuing demand for feathers for headdresses by local inhabitants of New Guinea have caused its near extermination. During the early 20th century, eighty thousand skins per year were exported from New Guinea by European settlers. As more and more forest is converted for agriculture, this species has become quite rare, as it requires intact forest as its habitat. Some other species of birds of paradise can adapt more readily to disturbed and cultivated areas and so are less vulnerable to extinction pressures. The use of modern firearms has accelerated the efficiency of hunting of a population already decimated by the loss of habitat.
ii) Bowerbirds: The colorful bowerbirds, which live in New Guinea and Australia, construct remarkable display grounds known as “bowers” out of sticks and grasses. They decorate the bowers with ornaments such as snail shells, fruits, flowers and – close to human habitation – the detritus of human civilization: buttons, bottle tops, shotgun cartridges. The female is courted by the male in his bower, where he displays his magnificent plumage, imitates bird calls and other forest sounds, and may offer the female some fruit.
iii) Kagu: The flightless kagu of New Caledonia has been isolated for eons by continental (or, in this case, “island”) drift. Ten million years ago New Caledonia was part of Australia, but it subsequently broke off, isolating all of its species. Many of these species are endemic. The peculiar kagus live and eat on the forest floor, and consume snails (which they crack with their bills), earthworms and other invertebrates. The kagu is a bird of the dense forest and was once common, but the population has been decimated by hunting and the loss of its forest habitat by logging, conversion for agriculture, and nickel mining. In addition, species introduced by humans have damaged the forest floor habitat of the kagu. Pigs disturb the soil; deer eat low-lying vegetation which shelters them; dogs kill them; and rats attack them. They are also in demand by zoos and for pets.
iv) Hornbills (Family Bucerotidae): Hornbills are large and spectacular birds of Southeast Asian primary forests. These birds live in flocks and forage high in the canopy. They have a distinctive bill with a huge “casque” or horny growth on the upper surface, which is hollow and acts as a resonating chamber when the bird calls. The bill also acts as a tool for obtaining fruit, for digging into trees for insects, for catching the small mammals and birds which are part of its diet, and for excavating nest holes in trees. The female lays her single egg in such a hole, subsequently incarcerating herself within it by constructing a wall of mud and saliva. She leaves a small slit through which her mate can feed her for the three months or more required for the egg to hatch and for the chick to become large enough to leave the nest. She also throws her fecal pellets out the slit! During this period, she loses all her feathers. The chick remains with its parents for several years, during which time the adults do not reproduce again.
v) Quetzal (Pharomachrus pavoninus): The quetzal is a bird of the Central American cloud forest at altitudes above 1500 meters. These forests are cool and very humid, which suits the conspicuous quetzal, with its brilliant red-and-green coloring and a three-foot-long tail. It is such a spectacular bird that its image became a very important one to the Maya and Aztecs, to the extent that it was incorporated into the plumed serpent deity Quetzalcoatl. Quetzals perch up high in the canopy, where they eat fruits and insects. However, they nest lower down in dead tree stumps, where they lay two eggs. Unfortunately these birds are now quite rare in accessible forests, where they are still hunted for feathers and for export as pets.
vi) Hoatzin (Opisthocomus hoazini): The hoatzin is a bizarre bird of the Amazon rainforest and was long thought to be related to Archaeopteryx, the reptile-like primitive bird, and therefore more closely related to dinosaurs than other birds. This association was made since the chicks are provided with two functional claws on the wing (as are found in Archaeopteryx fossils). They use them to pull themselves back to their nests after they have swum away from danger. These claws disappear at the time of the molt to the adult plumage. But it now appears that the hoatzin is instead related to the cuckoo and is not at all a “primitive” bird. It lives in trees along rivers and lakes, and is never found far from water. It is a poor flyer because of its diet, which consists almost entirely of the leaves of riparian (riverside) plants and some fruits – at least 52 different species! This necessitates a huge crop, almost 10% of the bird’s body weight, for microbial breakdown of these large quantities of greenery. Since the crop is very bulky, there is less room for flight apparatus and so the hoatzin remains, for the most part, sedentary. Two or three oblong pinkish-colored spotted eggs are laid and incubated by breeding pairs, while nonbreeding individuals act as assistants.
vii) Hummingbirds (Family Trochilidae): Mention should also be made of the magnificent hummingbirds so characteristic of neotropical rainforests, many of which delight us in northern regions during warm weather. This is a very large group in the Neotropics; Colombia has 143 species; Brazil, 90. These are tiny birds, almost the smallest of vertebrates, some of which may weigh less than two grams. Even the largest weigh only 18 grams or so. Hummingbirds have color vision, and are attracted to their food sources by the bright colors of flowers, such as the red and yellow flowers of epiphytes and bromeliads. They detect ultraviolet light reflections from flowers which use this device to captivate pollinators. They have very long bills for “sipping” nectar from flowers, and their bills are adapted to the shape and depth of the types of flowers which provide the preferred food for that hummingbird species. In fact, the hummingbird bill acts as a pumping mechanism for the rapid ingestion of nectar. It cannot waste time, since it is hovering while drinking. Hummingbirds may be able to consume as much as eight times their weight daily, and they must have a high sugar intake (although they may eat some small insects as well) because of their very high metabolic rate. Nevertheless, hummingbirds prefer nectar of a relatively low sugar concentration (around 20%) which prevents competition with bees, which pollinate and obtain nourishment from plants which produce nectar with high sugar concentrations (up to 80%). Because of this behavior, hummingbirds must visit thousands of flowers daily, making them important pollinating animals in rainforests, especially of bromeliads. Hummingbirds are able to hover above flowers because they have an extremely high frequency wing beat (up to 80 strokes per second, although 30 to 50 is more usual), especially when they are trying to escape. They can fly up, down, backwards, forwards, and sideways or even on their backs. Hummingbirds lay two relatively large eggs, which hatch in about two weeks.
viii) Raptors: Mention should be made of the many hawks, kites, eagles, vultures, and other carnivorous birds which abound in the tropics. As an example we can describe the white-bellied fish eagle (Haliaeetus leucogaster), which ranges from the Indian subcontinent to Southeast Asia, southern China, New Guinea and Australia. This bird is a medium-sized eagle, grey and white as an adult, with a black-and-white tail. It lives along coastal areas, although it may fly far inland in search of prey, and usually breeds in large trees (preferably more than 30 meters) on islands. It makes large nests about 1.5 meters in diameter, and, as with other eagles, the nest is reused many times. Two eggs are laid. This eagle feeds only on fish, which it catches by “gaffing” with its talons. It eats its prey “on the wing.”
a. Primates: Primates are found largely in tropical areas (90% of the approximately 200 species); few are temperate. (Perhaps this accounts for the eternal human seeking for warmth and sunshine!). Brazil and Madagascar together house 40% of all primate species; when one adds Zaire and Indonesia this figure rises to 75%. Brazil alone has 53 species (27% of the total number), of which many are endangered or almost extinct. Of these 53, thirteen are found nowhere else. Madagascar too possesses many (29) species of primates, all of which are lemurs, and most of which are unique. Forty per cent of lemur species are endangered (Mittermeier, 1988).
i) Tamarins: The black-chested mustached tamarin (Saguinus mystax) is a tiny monkey of the Peruvian and Brazilian Amazon. It is arboreal and lives on fruit and insects in mature rainforests, and seems unable to adapt to secondary forest. This monkey has black or dark brown fur all over, except around the nose and mouth, where short tufts of white hair form the “mustaches” of its name. The four species of lion tamarins are found exclusively in the almost-vanished Atlantic rainforest of Brazil and are therefore highly endangered. Amazingly, the black-faced lion tamarin, which has golden hair surrounding a black face, was not discovered until 1990. It lives on fruits and insects. This monkey is monogamous (unlike most primates), bears twins, and lives in small family groups. Both parents care for the offspring. Only 260 black-faced lion tamarins are thought to exist in the wild, making it one of the rarest mammalian species in the world. The golden lion tamarin, a highly colorful and appealing animal, is the most famous tamarin. Because of habitat loss, it is nearly extinct in the wild.
ii) Drill: The drill, a relative of the mandrill, is a rare monkey of the west-central African rainforest. Drills live in groups of about 25 related animals, and stay together despite attacks. This makes them relatively easy to catch since they are mainly terrestrial and not good aerialists. At present they are heavily hunted everywhere in their habitat (southeastern Nigeria, Cameroon, parts of Guinea) and by the early 1990’s had been reduced to perhaps 4000 individuals. The widespread ownership of guns after the Biafran War in the 1970’s has promoted the demise of most of these animals. No current population figures exist (McGrath, 2001).
b. Bats (Chiroptera): Multitudes of bats live in tropical forests, where they have important roles – mainly as insect eaters and fruit consumers (and therefore seed-distributors), although some are carnivorous or take blood for food.
i) Tube-nosed bat: These bats live in the Philippines on only three of the islands, Negros, Cebu and Sibuyan. They are unusual in that they have odd scroll-like nostrils, are striped and have yellow spots on their ears and wings. These bats live mainly in lowland forest in trees and plants and are fruit-eaters, like so many other species of tropical bats. Since they depend on intact lowland forest and have a limited distribution, they are highly endangered. Less than 1% of their original habitat remains on Negros Island, and they are rare on Sibuyan Island, and probably gone on Cebu (where virtually no lowland forest remains).
ii) Honduran white bat: These are frugivorous, small white bats with bright yellow noseleaves and ears. They live in Honduras, Nicaragua, and Panama, mostly on islands. They roost in small groups in “tents” of plantain leaves, which they cut along the midrib. The leaf then droops on each side and forms a shelter for the bats.
iii) Long-nosed bat: (Rhynchonycteris naso): These bats are found in the Neotropics, and are often seen since they roost in groups on tree trunks or branches or river banks, always near water. The roosting bats hang in a straight line, spaced about 1-2 inches apart. These are small brown bats, with some white markings. They are insectivores, and forage over the surface of rivers and lakes.
iv) False vampire bat: (Vampyrum spectrum): This is one of the largest of bats, having a wingspan of 80-90 cm [32-36 inches]. This bat of Central and South America is carnivorous, feeding on rodents, birds and other bats. They are monogamous, and live in family groups with their offspring until the young become of reproductive age. One of the group remains at the roosting site as a guardian for the young nestlings.
v) Vampire bat: (Desmodus rotundus): Although there are many fewer vampire bat species than fruit- or insect-eating bats, these animals have a fearsome reputation. All vampire bats are specialized for feeding on blood, which they accomplish by means of their extremely sharp incisor and canine teeth. They make a small painless cut in their prey and lap the blood which wells up and keeps flowing, since the bat’s saliva contains an anticoagulant. This is not so serious for a large mammal, but these bats are capable of taking sufficient blood in one feeding to kill wild birds. The thumbs of these bats are padded and can act as feet for its rapid walking or hopping. There are only three genera of vampire bats, each containing one species (this way of making a living is obviously tougher than catching insects or munching fruit). These are the common vampire bat, the white-winged vampire bat, and the hairy-legged vampire bat.
vi) Flying fox: The flying fox is actually a fruit-eating bat which lives in Malesian peat rainforests. Peat forests lie near waterways where the water table is very high, so that the soil is permanently waterlogged. Flying foxes are tree-dwelling bats, which cannot navigate by echolocation and so cannot fly when it is very dark. They locate their preferred fruits by smell and, to some extent, by sight. They reproduce slowly, producing only one offspring per year after a lengthy gestation period (6-8 months). They are social, long-lived and roost in large groups or “camps,” where they are the prey of eagles and other raptors. These bats are important in seed dispersal and flower pollination within the forest. However, in many areas, they are heavily hunted and trapped, partly for food, partly for medicine (flying fox meat is thought to cure asthma), and partly because they are thought to imperil the human profit from fruit collection. For example, in one small site in Sarawak (Borneo), 679 shotgun cartridge cases were found over a two-week period, indicating very heavy hunting (Gumal, 2001). Unfortunately, this activity is self-defeating, since without the flying foxes, pollination and therefore fruit production of some of the most popular fruits (such as the durian) would be severely affected. Bats visit two durian flowers per minute! The government of Sarawak has taken steps to protect the bats, but without restraint of the incessant logging activity occurring in Sarawak, habitat depletion in the long run (or short, given current deforestation rates in Borneo) is the most significant factor in their population decline. The cut areas in Sarawak are not allowed to reforest, but are used for oil palm plantations, aquaculture, and tree plantations – a pattern establishing itself all over this region.
c. Carnivora: Among the carnivores living in tropical forests are a few members of the dog family ( including foxes), bears, raccoons, weasels, skunks, otters, and felids (cats). The large cats attract a great deal of attention, although as top carnivores, they are present in relatively small numbers. They also require a great deal of territory for their hunts. [See elsewhere on this website for carnivorous mammals of Peru.]
i) Kinkajou (Potos flavus): The kinkajou is an American member of the Procyonidae, the raccoon family. It ranges from southern Mexico to southern Brazil. It is brown, with large wide-set brown eyes, a long prehensile tail (useful since it is arboreal), and some species have furry soles on their feet. It has five long curved claws, advantageous to this arboreal animal which lives in the canopy of mature or secondary rainforests. It is nocturnal and feeds on ants and fruits, especially those of the fig (Ficus) family, and some small vertebrates. It may also drink flower nectar. These animals disperse seeds of many important plants of the rainforest, among them figs and some hardwoods, such as Virola. The kinkajou has a single young.
ii) Margay: The margay is another arboreal, South American carnivore, a member of the cat family. It is small, and, like most arboreal creatures, has a long tail. It is highly secretive and rarely seen, although it preys on birds and small rodents. It gives birth to a single young after a long gestation period (2½ months) and thus has low fecundity.
d. Peccaries and Deer (Artiodactyla): There are many species of peccaries and deer in all tropical forests and they form a major part of the diet of the larger carnivores. The peccaries are related to pigs, but peccaries have small litters of one or two young. Peccaries are quite large, with thin legs, large heads on thick necks, and tiny tails. They are omnivores. [See elsewhere on this website for peccaries and deer of Peru.]
i) Collared peccary (Tayassu tajacu): A blackish animal with a yellowish “collar” running from its shoulder to its cheek, and distinctly smelly, the collared peccary lives in the Neotropics in groups of a few to twenty individuals. Fruits, invertebrates, snails, palm nuts and vegetation form its diet. They mark trails by scraping a declivity and defecating into it. They sleep in burrows, usually under tree roots, and are extremely wary and difficult to observe in the forest.
ii) Red Brocket deer (Mazama): Deer originated in Europe and Asia and spread throughout the tropics. They entered the South American tropical forests via North America during the Pliocene. These animals are ubiquitous in the tropics, but tend to be smaller than temperate climate deer. As with their relatives, they are grazers and browsers, and generally solitary. Some tropical deer are tiny (the mouse deer of Southeast Asia, for example, and two species of dwarf red brocket deer in South America). The red brocket deer eat a wide variety of plants, (more than 60 species in Suriname, according to Eisenberg, 1989), including fungi, and prefer fruits. They are mainly night feeders.
e. Rodents: Some very appealing and interesting rainforest denizens are rodents. Among these are the squirrels, mice, rats, tree rats, and cavy-like animals like the capybara, paca, and agouti.
i) paca (Agouti paca): The paca is an almost ubiquitous, medium-sized, virtually tailless brown animal with lines of white stripes along its body. It browses on vegetation and eats fruits and tubers, usually near the water. Pacas are monogamous and territorial, and are found in both pristine and secondary forests of South and Central America at elevations up to 3000 feet. Unfortunately for them, they are highly sought for their meat, and in areas close to human habitations they have become scarce or extinct.
ii) Brazilian porcupine (Coendou prehensilis): These large beasts (up to 5 kilograms in weight) are found in old secondary or vine forests of South America. Solitary animals, they feed on palm and other fruits and leaves. Because of their strong claws and prehensile tails, they are good climbers and can be found even in the canopy layers of the forest. They are nocturnal and during the day they sleep in holes in hollow trees or on tree branches. They range from rare to abundant, depending on the type of habitat available.
f. Marsupials: Marsupials are most distinguished for their unique mode of reproduction, in which the young are kept in the uterus for a very short period of time and, subsequent to birth, climb into a pouch on the mother’s belly to suckle and remain until they are mature enough to walk and feed on their own. In some species the lips of the young fuse with the mother’s teat. The babies’ forelimbs are well-developed, so that they can climb into the pouch, but other organs are still primitive. There are some marsupials in New Guinea, some islands of Indonesia, and of course tropical Australia; in the Neotropics, they are mainly found in South American forests.
i) Woolly Opossum (Caluromys): These opossums consist of several species ranging from Mexico to Paraguay. They are arboreal, have relatively large brains, and feed on fruits and occasional invertebrates and small vertebrates. They tend to forage in the canopy. Adaptations to arboreal life are a large tail and strong forelimbs. Gestation lasts only about 13-14 days and the babies (usually about three in number) remain attached to the mother’s teats for five to six weeks, after which they remain for a while in a nesting site. Other than the maternal association, these animals are not social
[See elsewhere on this website for mammals of Peru.]