Hoplomys gymnurus is a Neotropical rodent found in Central and South America. It ranges from southern Honduras to northwestern Ecuador and is never found east of the Andes Mountains.

Biogeographic Regions: neotropical (Native )

Hoplomys gymnurus has a long, narrow head with naked, erect ears. The hair on the dorsal part of the body is cinnamon-brown to dark brown. The anterior part of the body is covered with backward pointing spines. The spines are white at the base and black at the tip. The spines can be as long as 3 cm and as thick as 2 mm in diameter. The underside of the body and the inner parts of the legs and feet are white and there is usually a dark collar across the throat. The tail is naked and bicolored (dark on top and light colored below), but the tail is frequently lost in this species. Hoplomys is sometimes considered a subgenus of Proechimys, but H. gymnurus is much spinier than Proechimys.

Males are on average 38% larger than females.

Range mass: 0.220 to 0.820 kg.

Range length: 22 to 32 cm.

Sexual Dimorphism: male larger

• Terrestrial

Throughout its geographic range, Hoplomys gymnurus is found in primary forests, disturbed forests, deserted farmlands, palm swamps, and lowland tropical evergreen forests. However, H. gymnurus is considered a habitat specialist because it is usualy found near wet habitats, such as wet lowland rainforests and stream sides. In fact it lives in the wettest forest habitat in the world, the pluvial rainforests of western Columbia. It prefers stream sides with steep slopes, rocky banks, plenty of fallen logs and a tall canopy. Hoplomys gymnurus limits competition with a closely related, sympatric species, Proechimys semispinosus, by being a habitat specialist living in wet microhabitats.

Hoplomys gymnurus experiences two distinct seasons throughout its geographic range, a four month dry season from the middle or end of December to April and an eight month rainy season from May to December. The average rainfall is around 2,600 mm and 90% of the average precipitation falls during the rainy season.

Range elevation: 30 to 800 m.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: rainforest

Other Habitat Features: riparian

Hoplomys gymnurus is primarily a frugivore, but it also includes some insects in its diet. Most insects consumed are of the orders Coleoptera and Orthoptera, and soft seeds, bananas, wild figs, avocadoes, mangoes, and other fruits make up the majority of its diet. Fruit is most abundant at the end of the dry season and the beginning of the wet season. Haplomys gymnurus caches some foods in its burrow.

Animal Foods: insects

Plant Foods: seeds, grains, and nuts; fruit

Foraging Behavior: stores or caches food

Primary Diet: herbivore (Frugivore )

Hoplomys gymnurus is an important disperser of seeds of the palm Attalea butyraceae. It is also a reservoir for equine encephalitis and cutaneous leishmaniasis and is an intermediate host of Echinococcus oligarthrus. Equine encephalitis and cutaneous leishmaniansis are vectored by mosquitoes and sand flies, respectively.

Haplomys gymnurus also affects the ecosystem by changing habitats with its burrows and pathways. These actions can create microhabitats for smaller organisms. They also affect animals that they may steal burrows from. One excavation of a burrow that H. gymnurus was inhabiting revealed an extra cavity that was full of the eggs of an iguanid lizard.

Ecosystem Impact: disperses seeds; creates habitat

Commensal/Parasitic Species:

• Echinococcus oligarthrus

Some key predators of Hoplomys gymnurus are ocelots, jaguarundis, bushmasters, and other snakes.

The spines of H. gymnurus are a great defense mechanism against predators. In addition to the spines H. gymnurus can drop its tail to confuse or escape a predator.

Known Predators:

• ocelots (Leopardus pardalis)
• jaguarundis (Hepailurus yaguarondi)
• bushmasters (Lachesis muta)

Hoplomys gymnurus can emit a loud “whee-unk” sound with considerable force when confronted by another animal. The function of this vocalization is not known.

Communication Channels: acoustic

Perception Channels: visual ; acoustic

Little is known about the lifespan of Hoplomys gymnurus. Recaptures of wild individuals have occurred more than two years apart, but one researcher observed that H. gymnurus does not live more than 72 hours in captivity.

Average lifespan

Status: wild: 2 years.

Range lifespan

Status: captivity: 7 (high) years.

Hoplomys gymnurus is considered to be monogamous because of its habitat specialization and small home range. A mating pair usually shares a burrow and territory. The mating system may be more promiscuous, however, in areas of abundant suitable habitat.

Mating System: monogamous ; polygynous

In some parts of its geographic range, Hoplomys gymnurus breeds year round. It has a gestation period of 64 days and gives birth to one to three precocial young. Additional information on reproductive behavior for H. gymnurus is not available, but time of weaning is three to four weeks, and sexual maturity is reached at five months in the closely related species Proechimys semispinosus. In other parts of its range, H. gymnurus breeds seasonally. Pregnant females were found from February to July. This corresponds to the end of the dry season and beginning of the wet season. This also happens to be when food supply is at its peak.

Breeding interval: Armored rats breed year round if conditions allow, or if not, seasonally.

Breeding season: If breeding is seasonal it is from February to July.

Range number of offspring: 1 to 3.

Average number of offspring: 2.1.

Average gestation period: 64 days.

Range weaning age: 21 to 28 days.

Average age at sexual or reproductive maturity (female): 5 months.

Average age at sexual or reproductive maturity (male): 5 months.

Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous

Average birth mass: 24.3 g.

Average number of offspring: 2.1.

Hoplomys gymnurus gives birth to precocial young. The only parental investment is providing shelter and protection in the burrow and supplying food. Weaning happens three to four weeks after birth and the young start to develop spines at four weeks old to defend themselves.

Parental Investment: precocial ; female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)

Hoplomys gymnurus is uncommon, but not rare throughout its geographic range. Conservation may become important because it is a habitat specialist.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Hoplomys gymnurus is involved in the transmission of some human and animal diseases. Equine encephalitis has a mortality rate as high as 20% in humans and 80% in horses. Cutaneous leishmaniansis causes sores to develop on the skin of the infected person. Some of the sores can be very large and painful. Echinococcus oligarthrus is an extremely rare cause of human echinococcosis, but can be very dangerous to humans. Echinococcosis in humans causes cysts to form on internal organs like the liver and lungs.

Negative Impacts: injures humans (carries human disease); causes or carries domestic animal disease

Some native people of Panama eat Hoplomys gymnurus.

Positive Impacts: food