Oryzomys albigularis is also known as Nephelomys albigularis and was recently assigned to a new genus, Nephelomys.
There is no information available regarding communication and perception in Oryzomys albigularis. However, like most other rodents, it probably uses a combination of vision, hearing, taste and smell to perceive the immediate environment. In the lab studies, an extended period of sniffing and exploratory behaviors were recorded when new individuals were introduced to each other, suggesting that olfaction and touch play an important role in perception. Other sigmodontine rodents communicate intraspecifically via high pitched squeaks.
Communication Channels: chemical
Other Communication Modes: pheromones
Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical
Oryzomys albigularis is classified as a species of least concern on the IUCN's Red List of Threatened Species. It appears that little is known of this species populations trends in the wild, however, they are thought to be common throughout their geographic range and may be slowly declining. Although there are no major threats to the long-term persistence of this species, deforestation may prove detrimental in the future.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Although human contact with Oryzomys albigularis is extremely limited, this species may serve as a vector for a variety of zoonotic diseases. Oryzomys albigularis is host to a number of ectoparasites, including mites, fleas, and ticks that may harbor diseases that can be transmitted to humans or domestic animals. For example, Oryzomys albigularis is a known vector for the Pichinde virus in Colombia. This virus is highly infectious and fatal to rodents and has been spread to humans who have had close contact with this species. The Pinchide virus is asymptomatic in humans and successful treatment of this pathogen has not yet been determined.
Negative Impacts: injures humans (carries human disease)
There are no known positive effects of Oryzomys albigularis on humans. Encounters with people are limited since it is common only to high elevation forests in Central and South America.
As seed predators, Oryzomys albigularis is likely an important seed disperser throughout its geographic range. They probably help maintain the balance of grasses and smaller plants through frequent foraging as well. They also serve as the prey for lager to medium-sized carnivores throughout their geographic range in Central and South America.
Oryzomys albigularis is host for a range of arthropod ectoparasites, including types of fleas, ticks and mites. Extensive research has been done on the relationship between Oryzomys albigularis and the beetle species, Amblyopinus emarginatus and Amblyopinus tiptonis. Though it has been previously reported that these beetles are parasites of O. albigularis, recent evidence suggests that they have a commensal and possibly even mutualistic relationship. The beetles were only found on the rats during the night and do not appear to harm O. albigularis. Although the two beetle species are relatively large, Oryzomys albigularis showed no signs of even noticing the beetles' presence, suggesting coevolution with the beetles. There is strong evidence that both beetle species feed on mites and ticks found in the nesting area of the rats. Oryzomys albigularis is known to be parasitized by mites in the genus Gigantolaelaps.
Ecosystem Impact: disperses seeds; parasite
Commensal/Parasitic Species:
Oryzomys albigularis is primarily herbivores, but occasionally consumes small insects. Primary forage includes grasses and some roots, and an abundance of fruits and seeds. In captivity, a base diet of normal protein rich animal chow was supplemented with fresh fruits, vegetables, and seeds.
Animal Foods: insects
Plant Foods: wood, bark, or stems; seeds, grains, and nuts; fruit
Primary Diet: herbivore (Folivore , Granivore , Lignivore)
Oryzomys albigularis, also known as the Tome's Rice Rat, Montane Rice rat, and Nephelomys albigularis, is distributed in the mountains of Costa Rica and Panama in Central America. It is also common in the Andes Mountains in Colombia, ranging east through northern Venezuela and southwest through Ecuador, Peru and northwestern Bolivia.
Biogeographic Regions: neotropical (Native )
Oryzomys albigularis lives in high elevation forests within 1,000 and 3,000 m. It is usually found in wet environments, such as mountain top cloud forests or in forests adjacent to streams with high flow rates. This species is strictly terricolous and lives inside and around fallen trees and moss covered rock formations. Oryzomys albigularis are adequate swimmers and use streams to escape predators by diving into fast moving waters and swimming to the opposite bank.
Range elevation: 1,000 to 3,000 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; mountains
Lifespan of Oryzomys albigularis in the wild is unknown, and research under laboratory conditions is limited. Most male and female rats lived 100 days and none live to be older than 150 days.
Average lifespan
Status: captivity: 100 days.
Average lifespan
Status: captivity: 100 days.
Oryzomys albigularis is a large rat-like rodent with a head and body length ranging between 132 and 174 mm and an average mass of 61.9 g. It has a naked, non-penicillated tail that is usually equal to or slightly shorter than its body length. Like other Oryzomys species, it has a long and pointed snout, and its molars are mainly penta-lophodont. Oryzomyines are distinguished form other genera by the length of their lower second molar, which is twice the size of their lower third molar. Oryzomys albigularis has large feet, with an average length of 31.8 mm, making their hind foot length almost 22% of their head and body length. Finally, members of Oryzomys have a unique toe configuration, as the fifth toe is shorter than the fourth and is used to distinguish them from members of Isthmomys.
Tome’s rice rats have long, thick pelage that covers their entire body, including their hind feet. Fur color is slightly variable, ranging from dark reddish-brown to blackish-brown. Pelage along the sides of the body is light in color, and venter pelage is white to off-white in color. Their ears are scantly covered with blackish hair. Although males and females are similar in appearance, males are slightly larger than females.
Average mass: 61.9 g.
Range length: 132 to 174 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
There is no information available regarding potential predators of Oryzomys albigularis. It is likely that numerous predatory vertebrates, such as birds of prey (e.g., Falconiformes and Strigiformes), prey upon this species.
Based on lab studies, Oryzomys albigularis is thought to be monogamous; however, this has not yet been confirmed in the wild. A lack of strong sexual dimorphism and similar developmental patterns are also thought to suggest monogamy. Finally, O. albigularis displays biparental care, a behavioral characteristic common in monogamous species.
Mating System: monogamous
Breeding season and general mating behavior of Tome’s rice rats in the wild have not been documented. In captivity, however, females exhibit post-partum estrous, and mating occurs frequently throughout the year. Gestation lasts for 26.7 days on average, and litter size ranges between 3 and 5 pups, with an average of 3 pups per litter. On average, pups weigh 4.89 g at birth. Oryzomys albigularis has smaller litters, lactates longer, and has a slower growth rate than other sigmodontine rodents. Pups nurse for approximately 22 days and are about a third of their adult weight when weaning is complete. Most males reach sexual maturity by 47 days old, and most females reach sexual maturity by 52 days old. In laboratory settings, Oryzomys albigularis exhibits biparental care, which is common in monogamous species but not other rodents. Males help provide warmth and protection to offspring and even groom and carry young back into the nest after handling by researchers.
Range number of offspring: 3 to 5.
Average number of offspring: 3.
Average gestation period: 26.7 days.
Average weaning age: 22.1 days.
Range age at sexual or reproductive maturity (female): 26 to 93 days.
Average age at sexual or reproductive maturity (female): 51.94 days.
Range age at sexual or reproductive maturity (male): 32 to 64 days.
Average age at sexual or reproductive maturity (male): 46.81 days.
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous ; post-partum estrous
There is no information available regarding parental care of Oryzomys albigularis in the wild. In captivity, this species exhibits biparental care, which is common among monogamous species but uncommon among rodents. Males help to provide warmth and protection to offspring and even groom and carry young back into the nest after handling. Weaning is generally complete by 22 days after parturition. There is no information available regarding the average time to independence in this species.
Parental Investment: male parental care ; female parental care ; pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Female, Protecting: Male, Female)
Nephelomys albigularis, also known as the white-throated oryzomys[2] or Tomes's rice rat,[1] is a species of rodent in the genus Nephelomys of family Cricetidae. Described in 1860, it was the first Nephelomys species to be discovered.[3] It was originally described in the defunct genus Hesperomys as Hesperomys albigularis and considered related to the much smaller H. longicaudatus (currently Oligoryzomys longicaudatus).[4] By 1894, it was placed in Oryzomys, as Oryzomys albigularis, and associated with what is now Nephelomys meridensis.[5] In the early 1960s, the scope of the species was considerably expanded to include most of the species that are now in Nephelomys, as well as a single name, boliviae, that is currently a synonym of Euryoryzomys nitidus. From 1976 on, several of these were reinstated as separate species.[2]
In 2006, a phylogenetic analysis by Marcelo Weksler of the oryzomyine tribe, in which both Oryzomys and Nephelomys are classified, provided strong evidence that Oryzomys as recognized then was a polyphyletic genus. O. albigularis and one of its former synonyms, O. levipes, were included; they consistently clustered into a single group within a larger group that included species now placed in Hylaeamys, Euryoryzomys, Transandinomys, Handleyomys, and Oecomys.[6] Accordingly, the group of species around O. albigularis was reclassified into a new genus, Nephelomys, with albigularis as its type species. Since then, the species has been known as Nephelomys albigularis.[3] Of the seven synonyms still placed under N. albigularis in 2005,[2] five were reclassified as separate species, N. childi, N. maculiventer, N. moerex, N. pectoralis, and N. pirrensis, one (oconnelli) was placed under N. childi, and the last (villosus) was not mentioned.[3]
Before the other five species were recognized as separate, it was recorded as being distributed from northern Peru via the Andes of Ecuador and Colombia into eastern Panama and northwestern Venezuela.[2] No revised distribution has been published taking into account the recognition of the other species.[3] These have type localities in Panama, Colombia, and western Ecuador; the type locality of N. albigularis itself is also in Ecuador.[2] It is known from montane forest at altitudes of 900 to 3300 m.[1] It is nocturnal and omnivorous.[1]
Nephelomys albigularis, also known as the white-throated oryzomys or Tomes's rice rat, is a species of rodent in the genus Nephelomys of family Cricetidae. Described in 1860, it was the first Nephelomys species to be discovered. It was originally described in the defunct genus Hesperomys as Hesperomys albigularis and considered related to the much smaller H. longicaudatus (currently Oligoryzomys longicaudatus). By 1894, it was placed in Oryzomys, as Oryzomys albigularis, and associated with what is now Nephelomys meridensis. In the early 1960s, the scope of the species was considerably expanded to include most of the species that are now in Nephelomys, as well as a single name, boliviae, that is currently a synonym of Euryoryzomys nitidus. From 1976 on, several of these were reinstated as separate species.
In 2006, a phylogenetic analysis by Marcelo Weksler of the oryzomyine tribe, in which both Oryzomys and Nephelomys are classified, provided strong evidence that Oryzomys as recognized then was a polyphyletic genus. O. albigularis and one of its former synonyms, O. levipes, were included; they consistently clustered into a single group within a larger group that included species now placed in Hylaeamys, Euryoryzomys, Transandinomys, Handleyomys, and Oecomys. Accordingly, the group of species around O. albigularis was reclassified into a new genus, Nephelomys, with albigularis as its type species. Since then, the species has been known as Nephelomys albigularis. Of the seven synonyms still placed under N. albigularis in 2005, five were reclassified as separate species, N. childi, N. maculiventer, N. moerex, N. pectoralis, and N. pirrensis, one (oconnelli) was placed under N. childi, and the last (villosus) was not mentioned.
Before the other five species were recognized as separate, it was recorded as being distributed from northern Peru via the Andes of Ecuador and Colombia into eastern Panama and northwestern Venezuela. No revised distribution has been published taking into account the recognition of the other species. These have type localities in Panama, Colombia, and western Ecuador; the type locality of N. albigularis itself is also in Ecuador. It is known from montane forest at altitudes of 900 to 3300 m. It is nocturnal and omnivorous.
