Arenal Volcano National Park

Habitat and Range

Treetops conceal this bright species in lowland moist and wet forests, in some premontane wet forest and rainforest, and in disturbed habitats and mangroves. The frog can be found as high as 1,200 m, but tends to stay at low elevations.

The Leaf Frog lives from Mexico to eastern Panama.

Physical Description

The namesake huge red eyes, long, narrow body, and distinct coloration make this tree frog stand out among other species. The frog’s back is a bright green to help it blend into the treetops when the frog is sitting still. When it moves, it exposes bright orange hands and feet that have large, sticky finger disks, and dark blue thighs with white or cream vertical bars. When the frog sleeps, it rests on its white belly, keeping its bright hands and thighs folded out of sight. When the frog is startled, the flashes of bright color confuse its attacker as the frog escapes.

Biology and Natural History

The striking Red-Eyed Leaf (or Red-Eyed Tree) Frog has become a widely photographed and recognized amphibian in Central America.

In the forest this frog hides among branches during the day and dry times. It is more active during the rainy season, making trips to breeding ponds at night. Instead of hopping or walking like frogs that spend a lot of time on the ground, this frog climbs hand over hand through the trees. The adhesive disks on its toes and fingers help the frog cling to surfaces that are entirely vertical; this species also has a toe joint that keeps the toe disk flat on a surface no matter how the frog positions its feet. This frog can even parachute, by spreading out its gangly limbs and large feet and dropping from higher perches to lower branches.

On nights in the early rainy season, the tree frogs descend to breed. Males call “chock” as they move from perch to perch, waiting for a female to approach. When she does, the male climbs onto her back in the amplexus position and she begins to carry him around as they look for a site for their eggs. Males sometimes compete for a female, or a latecomer tries to remove a male already on the female’s back. A second male may even mount the female next to the first male (females are quite a bit larger than males) and share in fertilization as the female deposits the eggs. Before laying the eggs, she carries her mate(s) to water, fills her bladder, and then deposits the eggs where they will stay until they hatch, usually on the surface of a leaf hanging over water. She lays 20-50 eggs, the male fertilizes them, and then the female empties her bladder full of water on the eggs to keep them moist. The mating pair may repeat this process for up to 5 clutches of eggs that night. The female will lay eggs on two nights each breeding season.

When the tadpoles are ready to hatch, they wiggle free of the eggs and drop into the water below. Before they hatch, they may perish from drying out, predation, or slipping off the leaf too early. Bats, birds, and snakes may eat the adults despite the weak toxins in their skin.

Diet

The Red-Eyed Tree Frog feeds on moths, crickets, and other insects that are active at night.

Height/Weight

Adult females, at 51-71 mm, can be nearly twice the size of males, which are 30-59 mm.

Taxonomy

Order: Anura
Family: Hylidae

Habitat
They can live in the driest deciduous forests to the wettest tropical evergreen forests.

Range
Agoutis can be found between southern Mexico and northern Argentina.

Physical Description
Within its range, the agouti is the most frequently found diurnal mammal in low-to-middle elevation rain forest. This small mammal is related to guinea pigs and chinchillas and is a relative of the paca. The agouti is reddish brown to black with a white, yellow, or gray underside.

Biology and Natural History
The agouti is diurnal unless it is too severely hunted; then it becomes more active at night. It is an important seed disperser for plants in its habitat: the agouti buries food in small caches that it will recover if fruit becomes scarce. If it does not return to these seeds, they may grow into plants and replenish the sources from which the agouti feeds. An agouti is capable of eating seeds with very hard seed coats, because while eating it may sit on its haunches in order to watch for predators-this gives it time to work on the seed. While sitting on its back legs, it can use its forepaws to hold the seed in place and gnaw on a specific spot.

One or two baby agoutis are born at a time in one of their mother's several sleeping spots. They are born extremely developed, and are very active soon after birth. Early in the morning on their first day, the mother takes them to potential nest sites dug by other animals, often consisting of crevices or burrows. The babies choose one site and prepare their own nest with leaves and twigs. Agoutis nest in homes too small for predators to enter-but this means the mother is also too large to enter the nest site. Instead, she calls the young in the morning and evening to feed.

These mammals communicate extensively through odor signals. For example, they mark their trails and feeding and sleeping spots by dragging odor glands across objects. Males will even mark potential mates by spraying urine on them as part of their courtship ritual (pacas do this as well). Adult males defend their territory to ensure the paternity of their offspring.

While agoutis are not necessarily antisocial, an individual agouti avoids any other agouti that walks directly toward it, because such an action is presumably provocative. To fight, agoutis of the same sex may run towards each other, leap just before they make contact, and kick each other with their strong hind legs, which can cause serious damage to both fighters. In the presence of predators, however, their main defense is to flee, as they repeat high-pitched barks to warn family within the territory. If they are directly encountered by a predator, they will raise hairs on the rump to appear larger; if a predator tries to bite this large tuft of hair, they will miss the skin of the agouti and it will have a greater chance of escaping.

Diet
Agoutis eat mostly fruit, including the seeds.

Height/Weight
Head and body length ranges from 41.5 to 62 cm; they weigh about 4 kg.

Taxonomy
Order: Rodentia
Family: Dasyproctidae

Habitat
The paca generally stays in moist lowland habitats but may also live in seasonally arid areas near permanent streams or bodies of water.

Range
Pacas range from southern Mexico to northern Argentina.

Physical Description
This nocturnal mammal is larger than its relative the agouti, and is twice the agouti's weight. Generally brown to black, with four lines of white dots on each side of body, the agouti lives solitarily with the exception of a mother rearing her young.

Biology and Natural History
Pacas like to eat in the darkest places possible. If they are encountered with a threat, they can sprint quickly, but more often escape danger by leaping away and staying still for up to 45 minutes. Since they do not usually run to escape, they can store fat for times of scarcity, whereas the agouti stores food in caches in the ground. In addition to leaping and freezing to escape danger, pacas have a thin outer layer of skin that can tear very easily in the jaws or claws of a predator, so it is difficult to grasp them before they get away. Pacas may also escape by running to a body of water and submerging themselves; they may have developed this behavior in response to the now rare bush dog (Speothos venaticus).

To deter potential predators, pacas also use vocal sounds and grind their teeth to make an incredibly loud, ominous noise. A male will also roar and fight to defend his territory. When fighting becomes necessary, pacas battle by standing head to head and gnashing at each other with their large incisors. Pacas do not use odor signals to communicate as extensively as agoutis do, but like agoutis, male pacas marks potential mates by spraying urine on them as part of the courtship ritual.

An adult female occupies an exclusive home range except for her mate and young offspring. One infant, or rarely, twins, are born furry with open eyes; newborns stay in a burrow dug by the mother or previously used by an armadillo. During the day the mother will cover the entrance with leaves.

Diet
Pacas mostly eat fruits, nuts, seeds, and during some parts of the year, plant vegetation.

Height/Weight
The head and body length is approximately 60-80 cm; their short, vestigial tail is 2 cm long. They weigh about 10 kg. Adult males are usually 15% larger than adult females.

Taxonomy
Order: Rodentia
Family: Dasyproctidae