AnimaliaHighest rank in taxonomy. Groups all life into domains: Animalia, Plantae, Fungi, etc.IUCN LCInternational Union for Conservation of Nature — the world authority on species extinction risk, using standardized criteria. — Least Concern — widespread and abundant; not at immediate risk of extinction.In ProgressCurrent stage of this record in the editorial review workflow. Recent Sighting
Oligoryzomys fulvescens
Fulvous Pygmy Rice Rat
(Saussure, 1860)
Detailed Texts Multi-lang
A very small, slender rodent with a long tail and soft, yellowish-brown (fulvous) fur. It is highly agile, often exhibiting semi-arboreal habits.
Added by
Anonymous Curator
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Under Review
Last modified by
Julia Trouin
TaxonomyBiological classification ranks placing this species within the tree of life, from Kingdom down to Genus.
PhylumRank below Kingdom. Groups organisms sharing a fundamental body plan (e.g., Chordata = vertebrates and some invertebrates).Chordata
ClassRank below Phylum. Subdivides by structural traits (e.g., Mammalia, Aves, Reptilia, Insecta).Mammalia
OrderRank below Class. Groups related families sharing common ancestry (e.g., Carnivora, Primates).Rodentia
FamilyRank below Order. Groups closely related genera (e.g., Felidae = cats, Canidae = dogs).Cricetidae
GenusRank just above Species. The first word in the two-part binomial scientific name.Oligoryzomys
Taxonomic AuthorityThe scientist who first formally described and published this species, followed by the year of publication.(Saussure, 1860)
Record Completeness
95%Coming soon
Ecology & StatusHow this species lives: habitat preferences, diet, behavior, population status, and role in its ecosystem.
OriginWhether the species is native (evolved here), endemic (found only here), or introduced by human activity.
Native
Population TrendDirection of change in population size over time: increasing, stable, decreasing, or unknown.
Stable
Breeding SeasonTime of year when this species typically reproduces or flowers.
Year Round
Trophic RolePosition in the food chain: producer, herbivore, carnivore, omnivore, decomposer, or parasite.
Omnivore
Recent SightingsWhether this species has been observed in the wild in Costa Rica within recent years.
Yes
Habitat SummaryOverview of the specific ecosystems and environments where this species is found in Costa Rica. Multi-lang
Common in a wide variety of habitats including forests, grasslands, agricultural fields, and secondary growth throughout Central and South America.BehaviourDaily activity patterns, movement, territory use, foraging style, and seasonal behavioral changes. Multi-lang
Nocturnal and versatile; spends time on the ground and in low vegetation. Builds globular nests from dried grass.Social ActivitySocial structure: whether the species is solitary, paired, or colonial; hierarchy and communication. Multi-lang
Solitary, with males and females meeting primarily for mating.Feeding GuildWhat the species eats, how it forages or hunts, and its role as a consumer in the food web. Multi-lang
Small-scale generalist omnivore.Trophic Chain DetailsSpecific interactions in local food webs: prey species, predators, competitors, and scavengers. Multi-lang
Omnivorous; feeds on seeds, insects, and vegetative matter. Serves as a vital food source for many small predators.Reproductive BehaviourMating strategies, courtship displays, nesting or spawning behavior, and parental care. Multi-lang
High reproductive turnover; females are capable of multiple litters per year.Physical Measures
Length (cm)
6.0 - 9.0 cm
Weight (Grams)
10 g - 25 g
Offspring per cycleTypical number of young (live births, eggs, or seeds) produced by one adult in a single reproductive event or breeding season.3 - 6
Sexual DimorphismObservable physical differences between males and females of the same species (e.g., size, coloration, features).No
Lifespan
Sexual MaturityAge at which the individual becomes capable of reproducing for the first time.
2 - 3 Months
Gestation / IncubationDuration from fertilization to birth (mammals) or to hatching (egg-laying species).
20 - 25
Lifespan EstimatedExpected duration of life from birth to natural death under wild conditions.
Males1 - 1.5 Years
Females1 - 1.5 Years
Evolutionary AdaptationsInherited traits and behaviors that improve the species' survival and reproduction in its specific environment. Multi-lang
Equipped with specialized foot morphology and long tail for balance, facilitating agile movement in both terrestrial and low-canopy environments.
Main ThreatsDocumented pressures reducing the population: habitat loss, hunting, disease, climate change, and invasive species. Multi-lang
Low immediate threat level due to high adaptability and wide distribution, though localized habitat loss remains a factor.
Interesting FactsSurprising or notable facts that highlight what makes this species unique or ecologically important. Multi-lang
Like other pygmy rice rats, it is highly reproductive and can reach high population densities in favorable conditions.