Hutias

(Capromyidae)

Class: Mammalia

Order: Rodentia

Suborder: Hystricognathi

Family: Capromyidae

Thumbnail description
Medium to large stockily built rodents with broad rounded heads

Size
14–32 in (36–80 cm); 1.1–18.7 lb (0.5–8.5 kg)

Number of genera, species
8 genera; at least 24 species

Habitat
Forest, woodlands, scrub, cliffs, and mangroves

Conservation status
Extinct: 6 species; Critically Endangered: 6 species; Vulnerable: 4 species; Lower Risk/Near Threatened: 2 species

Distribution
Caribbean

Evolution and systematics

The Capromyidae represents a Caribbean radiation of the south and central American Hystricognath rodents closely allied to the Myocastoridae (coypu) and Echimyidae (spiny rats). Some subfamilies have been varyingly classified across all three families and the Myocastoridae is still included within the Capromyidae by some authorities.

Extensive extinction has occurred within this family and a number of additional species are known from Holocene fossil deposits. The exact extinction date of many is unclear and the possibility exists that some species believed to be extinct may still exist on small islands within the Caribbean.

The number of species is difficult to accurately assess with so many recent extinctions. Some sources cite as many as 33 species, although some of these are only known as sub-recent fossils. The status and correct taxonomic determination of many species is still unclear and the family is in need of taxonomic revision.

Physical characteristics

Hutias have many typical Hystricognath (caviomorph) features. They are heavily built rodents with broad rounded heads. They have relatively small eyes and short rounded ears. Tail length varies from around 80% of the head and body in Mysateles down to only 10% in Geocapromys. In Mysateles the tail is partially prehensile. The fur is generally thick but harsh and varies from dark, almost blackish, to very pale gray. Most species are paler ventrally.

Distribution

The entire family is endemic to the Caribbean. Many species have very restricted distributions to either a single or small group of islands. Extant species still occur on or in the cays around Cuba, Jamaica, the Bahamas, and Hispaniola. Three species are known only from their type localities, one of which, Mysateles garridoi, is known only from a single specimen. Only two species are considered to be relatively common where they occur, Capromys pilorides and Mysateles prehensilis.

Habitat

Hutias generally inhabit forested or rocky areas where they are mainly arboreal. They are known to climb well and use tree holes and rock crevices as dens. Mesocapromys auritus and M. angelcabrerai are known to build large obvious stick nests in areas of mangrove forest, some of which may be communal.

Most species are nocturnal, although Capromys pilorides is reported to be both nocturnal and diurnal. Geocapromys ingrahami occurs at densities of up to 30 individuals per hectare on East Plana Cay in the Bahamas occupying rough limestone cliffs and scrub. Very little ecological data exists on most species.

Behavior

They are generally regarded as living in social family groups, agonistic encounters are few and individuals appear not to be territorial. Reports of a solitary social structure may result from displaced individuals or very small families. Geocapromys and Capromys are tolerant of conspecifics in captivity and will live in loose groups. Communal nesting has been reported in both Mesocapromys and Plagiodontia in the wild. Social groups frequently groom each other and a variety of low vocalisations are used.

Runs in and around natural rock crevices and fecal deposits often reveal the presence of hutias. The large stick nests of some Geocapromys in the branches of mangrove forest can also reveal the presence of hutias in an area.

Feeding ecology and diet

Hutias are generally herbivorous feeding on a variety of bark, leaves, and fruits. They also occasionally eat lizards and other small animals. The stomach of Capromys is highly complex for a rodent, comprising three chambers each separated by a constriction. They possess open rooted molars and premolars that continue to grow throughout life.

Reproductive biology

Hutias give birth to small litters of highly precocial offspring following a relatively long gestation. The estrous cycle is normally 10 days, although in Capromys it has been reported as 16 days. Gestation in all species is between 110–150 days. A single infant is normal but litters of up to three for Geocapromys brownii or even six for Capromys pilorides have been known.

Young are highly precocial and mobile at birth, in most species weighing around 5–10% of adult weight. Breeding is probably aseasonal in the wild and up to two litters a year may be produced.

Conservation status

Hutias are highly threatened and many of the species are highly restricted island endemics. Two of the eight genera are totally extinct and a third, Isolobodon, is known only from skeletal remains and is most likely also extinct. Of the 13 extant species, only two are considered secure and the remaining 11 are all threatened or Near Threatened. In 2002 the World Conservation Union (IUCN) considers six of these to be Critically Endangered.

The major threats are hunting for food, deforestation of habitat for agriculture, and the introduction of cats, mongoose, and black rats. Despite most hutias being protected by law urgent conservation action is required to safeguard their survival.

Significance to humans

Hutias have long been used as a food source by native peoples in the region. Indeed, several species are known from skeletal remains in kitchen middens. They were moved between islands by people and possibly even partially domesticated. Some extinctions occurred prior to the arrival of Europeans in the region although these have accelerated since this time.

Species accounts

Resources

Lawlor, T. Handbook to the Orders and Families of Living Mammals. Mad River Press, 1979.

MacDonald, D., S. Norris, and D. W. MacDonald, eds. Encyclopedia of Mammals. Facts on File, Inc., 2001.

Nowak, R. M. Walkers Mammals of the World. 6th ed. Johns Hopkins University Press, 1999.

Vaughn, T. A., J. M. Ryan, and N. Czaplewski. Mammalogy. 4th ed. Brooks Cole, 1999.

Wilson, D. E., and D. M. Reeder, eds. Mammal Species of the World: A Taxonomic and Geographic Reference. 2nd ed. Smithsonian Institution Press, 1993.

[Article by: Mike J. R. Jordan, PhD]