Agoutis

(Dasyproctidae)

Class Mammalia

Order Rodentia

Suborder Hystricognathi

Family Dasyproctidae

Thumbnail description
Rabbit-sized, large-headed, short-eared, longlegged forest rodent with glossy fur and hind legs conspicuously longer than front legs, giving a "dragster-like" appearance when moving

Size
Dasyprocta: Head and body length, 12.6–25.2 in (32–64 cm); tail, 0.4–2.75 in (1–7 cm); weight, 1.3–8.8 lb (0.6–4 kg); Myoprocta: Head and body length, 12.6–14.9 in (32–38 cm); tail, 1.8–2.75 in (4.5–7 cm); weight, 1.3–2.8 lb (0.6–1.3 kg)

Number of genera, species
2 genera; 13 species

Habitat
Rainforest, secondary forest, scrub, cultivated areas and parks; to 6,560 ft (2,000 m)

Conservation status
Endangered: 2 species; Lower Risk/Near Threatened: 1 species; Vulnerable: 1 species; Data Deficient: 3 species

Distribution
Central and South America

Evolution and systematics

Fossils are known that date from the Oligocene of South America. The family Dasyproctidae belongs to the super-family Caviomorph of the suborder Hystricognathi. Caviomorphs probably evolved in Africa, and (along with cebid primates) crossed a then much-narrower Atlantic to South America in the late Eocene, where they diversified greatly. Many attained great size and occupied a number of ecological roles. Modern caviomorph diversity is but an echo of this. Of the two genera in the Dasyproctidae, the acouchis are considered to be the more primitive; they are smaller, have a longer tail, and exhibit simpler foraging patterns and social structure. The genus Dasyprocta has speciated widely in South America. In addition to the forest species, there are species in the open savanna-like habitat of the cerrado (D. azarae) and scrubby dry caatinga (D. prymnolopha).

Physical characteristics

These are glossy-furred, big-headed, rabbit-sized rodents with chunky bodies on long delicate legs. A prominent nose and whiskers, large eyes, and small ears perch high on the head. The tail is either a tiny nub and barely visible (Dasyprocta) or it is longer and readily visible (Myoprocta). Color is highly variable over the extensive ranges of the two genera; even within species, color variation can also be quite extensive. They are best distinguished from the larger and closely related pacas (Agoutidae) by the absence of prominent patterns of spots and stripes on the flanks. The scientific name is derived from the Greek dasus, meaning "hairy," and proktos, meaning "rump." Agoutis not only have hair on their rumps, but it is especially long hair.

Distribution

Agoutis range from southern Mexico to northern Argentina and Paraguay.

Habitat

Agoutis are associated with primary and secondary forest and scrub. They require some dense vegetation for cover, but often prefer open areas for foraging. Highly adaptable, agoutis are often associated with water, and they frequently display a distinct preference for using stream banks to make burrows.

Behavior

Agoutis are ground living and day active, unless heavily hunted. Their home range will often include several sleeping spots, often inside fallen hollow logs or under tree roots. These spots are so well used that well-beaten paths will radiate out from them into the forest, linking favored foraging and resting sites. A favorite food of jaguar and other large forest carnivores, agoutis and acouchis have many behaviors aimed at predator avoidance. They will freeze in mid-stride if threatened. If threats continue, they will run quickly through the forest, their passage assisted by their cone-shaped body form. When resting, they will sit in an erect body posture with feet and ankles flat on the ground, ready to dart

away if danger is sensed. From a standing position, they are able to leap over 6.5 ft (2 m) into the air.

Feeding ecology and diet

Agoutis eat primarily fallen fruit, but their diet also includes insects and shoots. They collect and store seeds and fruit, rarely eating those that have freshly fallen, preferring those in their various scattered and perpetually replenished larders. Some of their stores are forgotten, so agoutis and

achouchis are important dispersers of rainforest seeds. Burying the seeds not only reduces insect predation, but also provides the seeds with a better chance of establishing a good root system while germinating, thus reducing vulnerability to the stress of drought. Species such as Hymenaea courbaril originally evolved to be dispersed by large mammals (such as gompotheres) that went extinct in the Pleistocene. Agoutis are now the major disperser and Hymenaea germination rates are very low in areas in which agoutis have been hunted out. Some agouti seed larders are raided by other animals, including peccaries, coatis, and spiny rats. Food is generally eaten while the animal sits on its haunches and holds the food in its hands. This dexterity allows the rodent to manipulate the seed or fruit until the weakest spot is discovered; manipulation then ensures that this area remains under dental attack until the defensive walls are breached. In this way the agouti (and acouchi to a lesser extent) can break open and eat the contents of such hard fruits as the Brazil nut (Bertholecia excelsa).

Reproductive biology

Agoutis are capable of breeding throughout the year, whenever conditions (especially availability of fallen fruit) are favorable. The basic social unit is the mated pair; the pair bond lasts for life. Reproduction may occur twice a year, if food supplies permit. Unlike the familiar rats, mice, and hamsters, these rodents have small litters of large young in which they invest a great deal of time and parental care. The litter size is generally one or two, with occasional records of three and (very rarely) four. Lactation lasts for around 20 weeks. However, because of the high risk of predation, the young are precocial, being born fully furred, with open and functioning eyes and ears. They are well coordinated and able to run within an hour of birth. Gestation varies between 104 and 120 days. The estrous cycle is around 34 days.

Conservation status

The IUCN lists D. ruatanica and D. coibae as Endangered, D. azarae as Vulnerable, D. mexicana as Lower Risk/Near Threatened, and D. cristata, D. kalinowskii, and M. exilis as Data Deficient. The remaining species are not currently threatened.

Significance to humans

Agoutis are often heavily hunted and may constitute a regional mainstay for local hunters. They are a very important disperser of the seeds of rainforest trees.

Species accounts

List of Species

Central American agouti

Dasyprocta punctata

taxonomy

Dasyprocta punctata Gray, 1842, Realajo, Nicaragua.

other common names

English: Indian rabbit; Spanish: Guatusa, guaqueque alazan, neque.

physical characteristics

Head and body length, 12.6–25.2 in (32–64 cm); tail, 0.4–2.75 in (1–7 cm); weight, 1.3–8.8 lb (0.6–4 kg). Body color variable, leading to a plethora of subspecific names (11 in Central America alone). Body color varies from yellowish or orange, finely grizzled with black, to that of populations on the Atlantic slope of Costa Rica and Panama that have dark brown foreparts, orange mid-back, and a cream rump.

distribution

From Chiapas and Tabasco States, Mexico, south through Central America to southern Bolivia and northern Argentina.

habitat

Primary and secondary rainforest, at densities varying from one per 2.5 acres (1 ha) to one every 25 acres (10 ha). Also occurs in parks and gardens wherever there is sufficient food and cover.

behavior

Each mated pair holds a territory of 2.5–5 acres (1–2 ha). They stay together for life, but rarely forage together. Tolerant of other pairs if there is abundant food, the male will (in the dry season) aggressively defend the area against incursion, especially by other agoutis. During aggressive interactions, rival males may erect the long hairs covering the rump to form a fan-shaped crest, and thump the ground with their hind feet. There are a number of vocalizations, including a doglike bark, made when fleeing from danger. They make burrows in riverbanks and link them, along with temporary sleeping spots in hollow logs, with a series of paths.

feeding ecology and diet

Fruits are the main dietary staple, but they also eat freshwater crabs, fungi, and insects. They have been shown to be important dispersers for Virola nobilis (Myrisicaceae), a rainforest-canopy giant that is primarily dispersed by birds and monkeys. The agoutis act as secondary dispersers, foraging seeds from dung piles of the primary dispersers and dispersing them a second time when they deposit them in their food stashes.

reproductive biology

The social unit consists of a life-mated pair. Reproduction may occur once or twice a year. Courtship is initiated when the male sprays the female with urine, causing her to go into a "frenzy dance." After several interactions of spraying and dancing, the female permits the male to advance and mate. The young are raised in small nest holes, the entrance to which is too small to permit the ingress of most predators. The mother calls the young out twice a day to suckle. Young grow quickly and move through a succession of larger resting chambers. Weaning occurs at around five months. Soon afterwards, the newly aggressive parents drive off the current offspring. This may either announce the impending arrival of a new litter or of unfavorable conditions. Post-weaning mortality can reach 70%, with deaths being mainly due to starvation and predation by male coatis (Nasua).

conservation status

Not threatened.

significance to humans

Heavily hunted. Important source of meat in rural areas.

Red-rumped agouti

Dasyprocta leporina

taxonomy

Dasyprocta leporina (Linnaeus, 1758), Peninka, Suriname. Also known as Dasyprocta aguti.

other common names

English: Brazilian agouti, orange-rumped agouti; Spanish: Acure, picure.

physical characteristics

Head and body length, 12.6–25.2 in (32–64 cm); tail, 0.4–2.75 in (1–7 cm); weight, 1.3–8.8 lb (0.6–4 kg). Head, shoulders,

forelegs, and mid-back are a greenish brown; the rump is a dark red to bright fire orange (this may not be visible unless the rump hairs are erect). There is sometimes a crest of longer black hairs between the shoulders and up to the top of the head. The belly varies from shades of muddy to pure orange, sometimes with a white midline. Populations on Caribbean islands tend to be smaller than those on the mainland and are less colorful, being dark brown with long chocolate-colored hairs forming a "cape" over the shoulders.

distribution

Found in northeastern South America, ranging from northeastern Venezuela and the Guianas, south to south-central Brazil. They are also in the eastern Amazon basin. They also occur on the Lesser Antilles (Bermuda, Grenada, and Barbados), and in Trinidad and Tobago. They have been introduced onto the Virgin Islands.

habitat

Occur in primary and secondary forest growth. This species has a preference for areas with dense undergrowth and so is frequently found in natural clearings like tree falls and along riverbanks.

behavior

Monogamous pairs travel together and are most active in the early morning and later afternoon. They may also be active on bright moonlit nights.

feeding ecology and diet

Nuts are buried in seasons of plenty against times of scarcity. Although the agouti's spatial memory is good, some seeds get overlooked. These, buried in the ground, grow to replenish the forest; the agouti is an important disperser of forest tree seeds.

reproductive biology

One individual lived nearly 18 years in captivity.

conservation status

Not threateed.

significance to humans

Heavily hunted. An important source of meat in rural areas.

Roatán Island agouti

Dasyprocta ruatanica

taxonomy

Dasyprocta ruatanica Thomas, 1901, Roatán Island, 40 mi (64 km) off the coast of northern Honduras.

other common names

French: Agouti de l'Ile de Ruatan.

physical characteristics

Head and body length, 12.6–25.2 in (32–64 cm); tail, 0.4–2.75 in (1–7 cm); weight, 1.3–8.8 lb (0.6–4 kg). A classic case of island dwarfism. This species is like a small Dasyprocta punctata, the ancestral mainland species from which it is thought to be descended. The body appears brown with each hair having alternating black and yellow rings. Undersurface is a lighter brown, with a white spot on the chin and a yellow patch in the middle of the belly.

distribution

Only on Roatán Island, Honduras.

habitat

Occurs mainly in forest and vegetation heavily disturbed by humans.

behavior

Agoutis are diurnal and wary of humans. They have been observed to use bamboo patches for sleeping. They are attracted to bat roosts, under which they feed on dropped fruits. Recorded as spending 23% of time sitting and 22% feeding; walking, sniffing, and digging (unearthing or burying nuts or excavating burrows) occupied 29% of their time. Socially interactive muzzling reported as a frequent interaction in the island's dense agouti population. Scent marking with anal glands also observed. In aggressive interactions one animal will flee with rump hairs erect. No territorial behavior was observed, but food was abundant and supplemented by local people.

feeding ecology and diet

They are known to eat coconuts, hibiscus flowers (both introduced), and pods of indigenous leguminaceous trees. They also eat rice, oranges, and corn.

reproductive biology

This has not been studied in detail. Mothers have been observed being followed by single young in March. All females rebutted attempts of young to nurse, suggesting some breeding synchronicity. Young were seen experimentally sampling foodstuffs.

conservation status

Endangered. They are thought to have declined by 50% between 1985 and 1995.

significance to humans

They are hunted by local people. Their habitat is threatened by resort and hotel development. Resort management wishes to protect the agouti as an ecotourism attraction, but the habitat fragmentation the hotels have caused may destabilize the populations. The Honduran government is making strong efforts to protect the area.

Coiba Island agouti

Dasyprocta coibae

taxonomy

Dasyprocta coibae Thomas, 1902, Coiba Island, off southwestern Panama.

other common names

French: Agouti de l'Ile de Coiba.

physical characteristics

Head and body length, 12.6–25.2 in (32–64 cm); tail, 0.4–2.75 in (1–7 cm); weight, 1.3–8.8 lb (0.6–4 kg). The fur is a coarsely grizzled brown. Rump hairs are orange tipped, but not as conspicuously elongated as in mainland populations of D. punctata, from which it is presumably descendant. The body size is like that of D. punctata, but the tail is much longer than usual (to 1.18 in [3 cm]). The belly and throat are yellowish.

distribution

Coiba Island, Panama.

habitat

Occurs in deciduous seasonally dry forest.

behavior

Nothing is known.

feeding ecology and diet

Nothing is known.

reproductive biology

Nothing is known.

conservation status

Endangered. It is restricted to a very small area of declining habitat.

significance to humans

Not known.

Mexican black agouti

Dasyprocta mexicana

taxonomy

Dasyprocta mexicana Saussure, 1860, Veracruz, Mexico.

other common names

Spanish: Serete, guaqueque negro.

physical characteristics

Head and body length, 12.6–25.2 in (32–64 cm); tail, 0.4–2.75 in (1–7 cm); weight, 1.3–8.8 lb (0.6–4 kg). This species is characterized by black body fur. Under parts are grayish or olive; there are long black hairs on the rump, and the eyes are ringed with conspicuous patches of naked pink skin. Pink skin also shows up at the base of the ears, contrast with the black fur and black pigmented ears.

distribution

Occurs only in a small area of southeast Mexico in Veracruz, north Oaxaca, northwest Chiapas, and west Tabasco states.

habitat

Lives in evergreen forests and secondary growth, from lowlands to 1,970 ft (600 m).

behavior

Mostly diurnal. Mated pairs occupy territories of 2.5–5 acres (1–2 ha) in extent.

feeding ecology and diet

Known to eat fruit.

reproductive biology

Two precocial young are born during the dry season.

conservation status

Lower Risk/Near Threatened; was probably never common in its restricted range.

significance to humans

Hunted for food; it is also considered an agricultural pest.

Red acouchi

Myoprocta exilis

taxonomy

Myoprocta exilis (Erxleben, 1777).

other common names

None known.

physical characteristics

Weight is 2.2–3 lb (1–1.4 kg); shoulder height is 6.7–7.9 in (17–20 cm). Smaller than adult agoutis, but has a significantly longer tail. The eyes and ears are large compared to those of agoutis. They are often beautifully marked. The fur is coarse, stiff, and shiny. The upper parts are reddish, and the belly and throat are brownish or orange. The cheeks and muzzle are often yellow or orange. The tail is white underneath.

distribution

Found in northern South America, in two isolated populations: one in the east of the Amazon basin and the second in the foothills of the Colombian Andes. It is also found east to the Uaupes river basin.

habitat

Found in primary forest and avoids disturbed areas. It favors areas of dense vegetation such as natural tree-falls and areas dense with vines. It avoids swampy ground.

behavior

Diurnal, its activity starting at sunrise and tailing off until a second peak in the declining hours of daylight. Lactating females have four periods of activity, each separated by resting periods of three to four hours. Nocturnal activity is rare and normally due to disturbance by a perceived threat. It uses hollow logs as refuges during the day. It holds its tail erect to show white underside. When frightened, it will skip away, giving birdlike whistles. It does not use established paths through its territory, preferring to push through dense vegetation. Up to seven acouchis will share a territory, with females using dense vegetation more often than males. Individuals rarely travel together unless it is a female with dependant young. Group territories are not continuous.

feeding ecology and diet

An important agent of seed predation and dispersal in primary rainforests; it is known to cache seeds under leaf litter. Utilizes the seeds of the palm Astrocaryum paramaca. Such seeds are large and are cached individually. Other smaller seeds may be cached in groups. It is highly dependant on caches in the dry season.

reproductive biology

The litter size is usually two. In juveniles, males are more numerous than females. By adulthood, this has dropped to 1:1, reflecting the greater predation rates on young males who disperse farther than females. Mating system is not known.

conservation status

Not threatened.

significance to humans

Hunted for its meat in rural areas.

Green acouchi

Myoprocta acouchy

taxonomy

Myoprocta acouchy (Erxleben, 1777), French Cayenne, Guiana.

other common names

Spanish: Chachure, oatiara, curi, tintin, guatusa, papali, punchana.

physical characteristics

Head and body length, 12.6–14.9 in (32–38 cm); tail, 1.8–2.75 in (4.5–7 cm); weight, 1.3–2.8 lb (0.6–1.3 kg). The back and flanks are greenish or blackish, with reddish or orange on the throat, cheeks, and muzzle, and the belly and inner surface of the legs are generally yellow or white. The rump hairs have distinct bands of contrasting colors. The underside of the tail is prominently covered in short white hairs that contrast with the body colors.

distribution

Found in northern South America, east of the Andes, and in the western part of the Amazon basin.

habitat

Lives in primary lowland forest, proximity to water preferred. It is not found in disturbed and open areas.

behavior

Similar to red acouchi.

feeding ecology and diet

Similar to red acouchi.

reproductive biology

The estrous cycle is 42 days and the gestation period is around 99 days. The litter size is two (exceptionally three), each of which weighs approximately 3.5 oz (100 g) at birth and is fully furred and is born with open eyes. The female has four pairs of mammae. Time to wean can be as short as 14 days. In both sexes puberty is reached in eight to 12 months. Has lived more than 10 years in captivity. Mating system is not known.

conservation status

Not threatened.

significance to humans

Hunted for meat.

Resources

Books

Eisenberg, J. F., and K. H. Redford. Mammals of the Neotropics. Vol. 3, The Central Tropics: Ecuador, Peru, Bolivia, Brazil. Chicago: University of Chicago Press, 1999.

Reid, F. A. A Fieldguide to the Mammals of Central America and Southeast Mexico. Oxford: Oxford University Press, 1997.

Periodicals

Asquith, N. M., J. Terborgh, E. Arnold, and C. M. Riveros. "The Fruits the Agouti Ate: Hymenaea courabil Seed Fate When Its Disperser Is Absent." Journal of Tropical Ecology 15: (1999): 229–235.

Dubost, G. "Ecology and Social Life of the Red Acouchy, Myoprocta exilis; Comparison with the Orange–rumped Agouti, Dasyprocta leporina." Journal of Zoology 214 (1988): 107–123.

Lee, T. E. Jr., K. R. Rhodes, J. L. Lyons, and D. K. Brannan. "The Natural History of the Roatán Island Agouti (Dasyprocta ruatanica), A Study of Behavior, Diet and Description of Habitat." The Texas Journal of Science 52:(2000): 159–164.

Forget, P-M. "Scatterhoarding of Astrocaryum paramama by Proechimys in French Guiana: Comparison with Myoprocta exilis." Tropical Ecology 32: (1991): 155–167.

Forget, P-M., and T. Milleron. "Evidence for Secondary Seed Dispersal by Rodents in Panama." Oecologia 87 (1991): 596–599.

Adrian A. Barnett, PhD