Geographic Range
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
Habitat
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.
- Habitat Regions
- tropical
- terrestrial
- Terrestrial Biomes
- rainforest
- Other Habitat Features
- riparian
Physical Description
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.
- Other Physical Features
- endothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
Reproduction
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.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- year-round breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
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
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-independence
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
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.
Behavior
Hoplomys gymnurus
is nocturnal and terrestrial. It builds simple horizontal burrows in the sides of
streams or uses abandoned burrows from other animals. The burrow consists of a 1.5
to 2 meter long tunnel with an enlarged chamber at the end for nesting. The nest chamber
is kept dry and is covered with vegetative matter. There is also a separate chamber
for defecating. Members of this species spend most of the day in their burrows and
come out at night to find food. They build elaborate pathways in the vegetation on
the forest floor which they travel through. Individual
H. gymnurus
is reclusive and runs to its burrow when disturbed. It has a rabbit-like gait when
running and can jump 22 cm in the air from a standing position.
- Key Behaviors
- terricolous
- fossorial
- nocturnal
- motile
- solitary
- territorial
Home Range
The home range of
Hoplomys gymnurus
is usually small and centered around its burrow. Its home range size also depends
on the amount of microhabitat available.
Haplomys gymnurus
cannot tolerate dry areas and will not wander far from a stream or other wet environment.
Communication and Perception
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
Food Habits
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
Predation
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.
Ecosystem Roles
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
Economic Importance for Humans: Positive
Some native people of Panama eat
Hoplomys gymnurus
.
- Positive Impacts
- food
Economic Importance for Humans: Negative
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
Conservation Status
Hoplomys gymnurus
is uncommon, but not rare throughout its geographic range. Conservation may become
important because it is a habitat specialist.
Additional Links
Contributors
Matthew Wund (editor), University of Michigan-Ann Arbor.
Patrick Cusick (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- 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.
- riparian
-
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- monogamous
-
Having one mate at a time.
- polygynous
-
having more than one female as a mate at one time
- 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).
- seasonal breeding
-
breeding is confined to a particular season
- year-round breeding
-
breeding takes place throughout the year
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- young precocial
-
young are relatively well-developed when born
- female parental care
-
parental care is carried out by females
- fossorial
-
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- territorial
-
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
- acoustic
-
uses sound to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- stores or caches food
-
places a food item in a special place to be eaten later. Also called "hoarding"
- food
-
A substance that provides both nutrients and energy to a living thing.
- causes or carries domestic animal disease
-
either directly causes, or indirectly transmits, a disease to a domestic animal
- herbivore
-
An animal that eats mainly plants or parts of plants.
- frugivore
-
an animal that mainly eats fruit
- 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.
- 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.
References
Adler, G., D. Tomblin, T. Lambert. 1998. Ecology of two species of echimyid rodents ( Hoplomys gymnurus and Proechimys semispinosus ) in central Panama.. Journal of Tropical Ecology , 14: 711-717.
Buchanan, O., T. Howell. 1965. Observations on the natural history of the thick-spined rat, Hoplomys gymnurus , in Nicaragua.. Annals and Magazine of Natural History , 13: 549-559.
Derlet, R. 2002. "CBRNE - Venezuelan Equine Encephalitis" (On-line). eMedicine. Accessed March 30, 2004 at http://www.emedicine.com/emerg/topic886.htm .
Eisenberg, J., K. Redford. 1999. Mammals of the Neotropics: The Central Neotropics, Vol. 3 . Chicago: University of Chicago Press.
Emmons, L. 1997. Neotropical Rainforest Mammals: A Field Guide 2nd ed. . Chicago: University of Chicago Press.
Grzimek, B. 2003. Armored Rat. Pp. 453-454 in Grzimek's Animal Life Encyclopedia , Vol. Vol. 16, 2nd Ed. Edition. Farmington Hills, MI: Gale Group.
Mendez, E. 1993. Los Roedores De Panama . Panama City, Panama: Impresora Pacifico, S.A..
Nowak, R. 1997. "Armored rat, or thick-spined rat" (On-line). Walker's mammals of the world online 5.1. Accessed March 24, 2004 at http://www.press.jhu.edu/books/walkers_mammals_of_the_world/rodentia/rodentia.echimyidae.hoplomys.html .
Reid, F. 1997. Field Guide to Mammals of Central America and Southeast Mexico . UK: Oxford University Press.
Tomblin, D., G. Adler. 1998. Differences in habitat use between two morphologically similar tropical forest rodents.. Journal of Mammalogy , 79(3): 953-961.
Wright, S., H. Duber. 2001. Poachers and forest fragmentation alter seed dispersal, seed survival, and seedling recruitment in the palm Attalea butyraceae , with implications for tropical tree diversity.. Biotropica , 33(4): 583-595.
NatureServe. 2003. "InfoNatura: Birds, mammals, and amphibians of Latin America" (On-line). Accessed March 30, 2004 at http://www.natureserve.org/infonatura/servlet/InfoNatura?searchName=Hoplomys+gymnurus .
CDC. 2002. "Parasites and Health: Echinococcosis" (On-line). Accessed March 31, 2004 at http://www.dpd.cdc.gov/dpdx/html/Echinococcosis.htm .
CDC. 2000. "Parasitic Disease Information Factsheet: Leishmania Infection" (On-line). Accessed April 01, 2004 at http://www.cdc.gov/ncidod/dpd/parasites/leishmania/factsht_leishmania.htm .