Myoprocta prattigreen acouchi

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Geographic Range

Green acouchies (Myoprocta pratti) are native to South America and their distribution extends from the Andes to the Río Negro, south of the Amazon in Brazil and Peru and north of the Amazon in Colombia, Ecuador, and Venezuela. Although the range of red acouchies does not typically overlap with that of green acouchies, both species are sympatric in central Colombia and are known to hybridize in this area. (Emmons, 1997)

Habitat

Green acouchies live in arid-land forest and tropical rainforest habitats, making their homes in the dense undergrowth. They dig shallow holes which serve as nests, or otherwise use hollow logs or abandoned burrows. Acouchies prefer habitats near rivers and marshes. Although most populations inhabit lowland forests, the subspecies Myoprocta pratti archidonae lives along the eastern face of the Andes at an elevation of 2,400 ft (731 m). (Emmons, 1997; Lönnberg, 1925; Morris, 1962)

  • Range elevation
    0 to 731 m
    0.00 to 2398.29 ft

Physical Description

Green acouchies are small, hystricomorphous rodents weighing from 0.8 to 1.2 kg, with body lengths ranging from 298 to 383 mm. Like other members of the family Dasyproctidae, green acouchies have long, thin legs, short ears, a short tail, and generally cylindrical body shape. On each hind foot are three toes with long hoof-like claws. They have four toes, and a vestigial thumb with claw on each forefoot. Their whiskers are long and black. The dorsum is covered in grizzled, olive-green, fur, and each individual hair has alternating black and yellow bands. Their course pelage is longer over the rump but does not overhang the area as it does in red acouchies. Ventral pelage is pale orange, fading to white on the throat, chest, and mid-ventral region. Typically they have a bright yellow stripe behind the ear, although in the Andean subspecies, this patch is ochraceous orange. Young green acouchies have a similar appearance to adults, with more pronounced orange coloration in their fur. (Emmons, 1997; Kleiman, 1970; Lönnberg, 1925)

  • Range mass
    0.8 to 1.2 kg
    1.76 to 2.64 lb
  • Range length
    298 to 383 mm
    11.73 to 15.08 in

Reproduction

Green acouchies form monogamous pair-bonds, and the success and growth rate of offspring is dependent on the maintenance of parental pairs. When preparing to mate, males select a single female with whom they begin courtship. After an introductory approach, males initiate anogenital sniffing, followed by heavy tail-wagging, trembling, and rapid stepping or drumming of the front feet. If the female remains in place, the pair may begin grooming one another; however, foot drumming typically initiates a chase. Females continually walk away from males, pausing periodically to perform a “sex-crouch,” in which the back is lowered, and the rear and tail are raised to encourage pursuit. Males follow and frequently try to spray females with urine. If females continue to wander, males begin to move more rapidly and forcefully chase them with leaps and squeals until they either mount the female or courtship is discontinued. (Kleiman, 1970; Kleiman, 1971; Morris, 1962)

Green acouchies reach sexual maturity at 8 to 12 months, with specific timing depending more on body weight than on age. Like most other hystricomorph rodents, female green acouchies have a vaginal closure membrane, which is open during estrus or when birthing young. Estrus lasts approximately 40 days. Breeding takes place year-round, however, peak reproductive activity occurs from January to June, resulting in an elevated summer birthrate. Gestation lasts for an average of 99 days, with young typically born in litters of one or two. Newborn green acouchies are precocial, born with eyes open, and are capable of walking outside the nest within 1 to 2 days after birth. Although newborns can eat solid foods during their first week, they are not truly weaned until 6 to 8 weeks after birth. If they are weaned before two weeks old, acouchies show stunted growth and development. (Kleiman, 1970; Weir, 1971)

  • Breeding interval
    Green acouchies breed approximately every 3 to 4 months
  • Breeding season
    Year-round (with peak activity occurring from January to June)
  • Range number of offspring
    1 to 3
  • Range gestation period
    94 to 101 days
  • Average gestation period
    99 days
  • Range weaning age
    6 to 8 weeks
  • Range age at sexual or reproductive maturity (female)
    8 to 12 months

In addition to nursing, green acouchy mothers exhibit several types of parent care toward their offspring. Prior to birthing young, females, and sometimes males, construct small nests where they give birth. Once birthed, young are groomed extensively by their mothers, which continues periodically for more than two months after parturition. New born acouchies are capable of self grooming 1 week after birth. For two weeks after parturition, mother acouchies emit a purring sound to encourage nursing. Purring is also though to help young identify their mother from other acouchies. Nursing is only initiated in the nest. If young stray from the nest, mothers grab them in their mouths and carry them back to the nest. If another animal approaches the nest, mothers respond aggressively by attacking the intruder or threatening it with whining and piloerection. Female green acouchies are known to cross-foster (i.e., nurse and care for) the young of other females. (Kleiman, 1972)

  • Parental Investment
  • precocial
  • male parental care
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • protecting
      • female
  • post-independence association with parents

Lifespan/Longevity

There is no information available regarding the lifespan of green acouchies.

Behavior

Green acouchies are diurnal but show peak activity towards dusk. Although behaviors in the wild are extremely difficult to observe due to the species’ evasive behavior, laboratory studies have identified a number of traits and social behaviors that are assumed to be widespread. Green acouchies live in small social groups with established hierarchies, maintained in part through agonistic behavior, including rearing and biting at one another, mouth-gaping, teeth-gnashing, and piloerection. To show submission, acouchies may respond by prostrating themselves (i.e., playing dead) or with high-pitched squeals. Males also occasionally scent-mark following an agonistic encounter, which may be related to territory defense; however, due to the limitations of laboratory study, the presence and extent of true territoriality in green agouchies is unknown. (Morris, 1962)

Green acouchies create and maintain a series of trails through the forest underbrush which they use on a daily basis, particularly when fleeing or chasing a rival. All acouchies in a social group may share the same set of paths, and all participate in maintaining them by fastidiously clearing away obstacles and packing the surface with their feet. Even as fully-grown adults, green acouchies practice “play-prancing,” a behavior in which they jump repeatedly up and down, while turning. Play-prancing does not appear to occur in groups exhibiting social tensions. (Morris, 1962)

Home Range

There is no information available regarding the home ranges of green acouchies. However, it is possible its ranges are similar to those of red acouchies, which span from 9,600 to 12,000 m^2 during the wet season, and from 6,500 to 7,300 m^2. during the dry season. (Nowak, 1999)

Communication and Perception

Despite the prevalence of intraspecific attacks, green acouchies display many cooperative communication behaviors. When individuals notice a potential threat, they rapidly stamp their feet in a timed pattern, using the noise to warn fellow group members. Those who hear the warning, become still and soon begin stamping themselves. Additionally, if exploring new territory, an isolated acouchy may perform “lost-calling” to contact other individuals, though this is more typically performed by juveniles than adults. (Morris, 1962)

Food Habits

Green acouchies are herbivorous, with a broad diet that consists of roots, fruits, nuts and seeds. Acouchies clean and prepare their food very carefully before consuming it, a habit assumed to prevent ingestion of toxins present in many vegetable and fruit peels. They also exhibit the unique behavior of scatter-hoarding in which individual food items are deliberately buried in separate locations rather than in a single cache. Not all edible items are cached; green acouchies prefer to cache those that are relatively large and hard. The chosen object is carried in the mouth while a pit is dug. The seed or nut is then deposited, stamped into place, and re-buried with the forefeet. Often, acouchies use a leaf or piece of bark to mark the location of the cache. (Morris, 1962)

  • Plant Foods
  • roots and tubers
  • seeds, grains, and nuts
  • fruit

Predation

Green acouchies are prey to a large number of rainforest-dwelling species, including humans. Known predators include South American coatis, white-nosed coatis, and jaguars. Their coloration likely helps camouflage them from predators and their burrowing lifestyle helps reduce risk of predation. (Cooke and Bruce, 2004; Emmons, 1997; "Red Acouchi", 2011)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Green acouchies are herbivorous. As scatter-hoarders, they aid in the dispersal of many plant species, particularly as nut and seed deposits are deliberately isolated and may easily be forgotten. Common throughout their geographic range, green acouchies are an important prey item for a number of different predatory species. (Cooke and Bruce, 2004; "Red Acouchi", 2011; Morris, 1962)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Green acouchies are hunted throughout their geographic range for their meat. Although rare, individuals may also be kept as household pets. (Catzeflis, et al., 2010; Emmons, 1997)

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

There are no known negative effects of Myoprocta pratti on humans.

Conservation Status

Myoprocta pratti is classified as a species of "least concern" on the IUCN's Red List of Threatened Species, as it is abundant and widespread throughout its geographic range. Current threats include hunting and trapping. (Catzeflis, et al., 2010)

Other Comments

Myoprocta pratti and Myoprocta acouchy were once considered the same species. As a result, out-dated literature may refer to the green acouchy as Myoprocta acouchy, which is now considered a separate species, the red acouchy. In South America, green acouchies are known as "cutiaras," "chacures," "punchanas," and "tintíns." (Emmons, 1997)

Contributors

Elyssa Juni (author), University of Michigan-Ann Arbor, Phil Myers (editor), University of Michigan-Ann Arbor, John Berini (editor), Animal Diversity Web Staff.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

young precocial

young are relatively well-developed when born

References

ITV Studios. 2011. "Red Acouchi" (On-line video). itvWILD. Accessed April 17, 2011 at http://www.itvwild.com/clip/1468.

Catzeflis, F., M. Weksler, C. Bonvicino. 2010. "Myoprocta pratti" (On-line). The IUCN Red List of Threatened Species. Accessed April 06, 2011 at http://www.iucnredlist.org/apps/redlist/details/136663/0.

Cooke, F., J. Bruce. 2004. The Encyclopedia of Animals, A Complete Visual Guide. Berkeley and Los Angeles: University of California Press.

Emmons, L. 1997. Neotropical Rainforest Mammals: A Field Guide. Chicago: The University of Chicago Press.

Kleiman, D. 1972. Maternal Behavior of the Green Acouchi (Myoprocta pratti Pocock), a South American Caviomorph Rodent. Behaviour, Vol. 43, No. 1/4: 48-84.

Kleiman, D. 1970. Reproduction in the Female Green Acouchi, Myoprocta pratti Pocock. Journal of Reproduction and Fertility, 23: 55-65.

Kleiman, D. 1971. The Courtship and Copulatory Behavior of the green Acouchi, Myoprocta Pratti. Zeitschrift für Tierpsychologie, Vol. 29, Issue 3: 259-278.

Lord, R. 2007. Mammals of South America. Baltimore: John Hopkins University Press.

Lönnberg, E. 1925. Notes on Some Mammals from Ecuador. Journal of Mammalogy, Vol. 6, No. 4: 271-275.

Morris, D. 1962. The behavior of the green acouchy (Myoprocta pratti) with special reference to scatter hoarding. Proceedings of the Zoological Society of London, 139: 701-733.

Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore and London: John Hopkins University Press.

Weir, B. 1971. Some Observations on Reproduction in the Female Green Acouchi, Myoprocta pratti. Journal of Reproduction and Fertility, 24: 193-201.

Wilson, D., D. Reeder. 2005. Mammal Species of the World, a Taxonomic and Geographic Reference. Washington, D.C.: Smithsonian Institution Press.