The optic nerve of ichthyomyine species is comparably smaller than that of other muroid tribes. Thus, it is likely that Neusticomys monticolus greatly depends on senses other than sight. It has relatively large ears, suggesting well-developed hearing, and long vibrissae suggest a dependence on haptic perception. Neusticomys monticolus has a set of well-developed planter pads on the hind and fore feet, which may be important in haptic perception.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Neusticomys monticolus is widely distributed and abundant throughout its geographic range and is classified as a species of "least concern" on the IUCN's Red List of Threatened Species. In addition, much of the geographic range of N. monticolus is located throughout protected national forestland in Ecuador and Columbia. Deforestation is a potential threat, however this has not yet become a major cause for concern.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse effects of Neusticomys monticolus on humans.
There are no known positive effects of Neusticomys monticolus on humans.
Neusticomys monticolus is primarily insectivorous and may help control insect pest populations throughout their geographic range. They are also prey for crab-eating foxes and probably a number of other carnivorous mammals, birds, and snakes. Neusticomys monticolus is generally uncommon and likely has little impact on its local environment.
Neusticomys monticolus is an opportunistic feeder and forages on that which is immediately and readily available. Neusticomys monticolus is primarily insectivorous, feeding on insects and arachnids including beetles, flies, mayflies, stoneflies, caddisflies, moths and butterflies, and spiders. Although stomach content analysis in N. monticolus shows evidence for folivory, ingestion of plant material in this species is probably rare.
Animal Foods: insects; terrestrial non-insect arthropods; aquatic or marine worms; aquatic crustaceans
Plant Foods: leaves
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)
Neusticomys monticolus is found in the Andes mountains of west Columbia and northern Ecuador, in particular in the Cordillera Central and Occidental mountain ranges of Columbia.
Biogeographic Regions: neotropical (Native )
Neusticomys monticolus is often found in heavily wooded areas along streams and small rivulets. These streams often run through constricted ravines that are tributaries to bigger watercourses and eventual rivers. Neusticomys monticolus is often found near small waterfalls around 2m in height and prefers riverine habitat covered by roots, cobbles, moss-covered rocks, gravel, and coarse sand. It has also been found in marsh-like areas surrounded by shrubs and shrub-like plants. This species commonly occupies elevations ranging from 1,800 to 2,777 m. High elevation populations tend to live along fast-flowing streams compared to low-elevation populations. Neusticomys monticolus lives sympatrically with other ichthyomyine species.
Range elevation: 1,800 to 3,754 m.
Average elevation: 2,777 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest ; mountains
Aquatic Biomes: rivers and streams
Wetlands: marsh
Other Habitat Features: riparian
There is no information available regarding the life span of Neusticomys monticolus.
Neusticomys monticolus has thick, blackish-gray pelage on its dorsum and slightly paler pelage on its venter. Subtle black guard hairs sporadically occur along the dorsum. Neusticomys monticolus has relatively large ears, ranging from 9 to 10 mm in length. Its tail ranges from 82 to 111 mm and is covered in gray-black fur. Their vibrissae range in color from black to white. Silvery white hairs occur on the digits of both the forefoot and hindfoot, which are used to distinguish N. monticolus from other ichthyomyines. Slight webbing is present between the 1st interphalangeal joints on the hindfeet. Interphalangeal webbing and thick pelage, are specializations for swimming. The pelage does not change in color or texture as the species matures in age. Sexual dimorphism has not been documented in this species.
Average mass: 40 g.
Range length: 192 to 223 mm.
Average length: 208.3 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
There is limited information regarding major predators of Neusticomys monticolus. Remains of N. monticolus have been discovered in the scat of crab-eating foxes. Their coloration likely helps camouflage them from potential predators.
Known Predators:
The mating system of Neusticomys monticolus or its ichthyomyine relatives has not been documented.
Little information is available regarding the reproductive behavior of Neusticomys monticolus. It is suspected that individuals breed during the end of the dry season and beginning of the wet season, which roughly spans the months of May and June. Females give birth 1 to 2 offspring per litter.
Breeding season: May through June.
Range number of offspring: 1 to 2.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
There is no information available regarding parental care in Neusticomys monticolus. As mammals, however, females gestate babies internally and nurse newborn young until weaning.
Parental Investment: altricial ; female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)
The montane fish-eating rat (Neusticomys monticolus) is a species of semiaquatic rodent in the family Cricetidae. It inhabits the Andes Mountains of Colombia and Ecuador.
Montane fish-eating rats are moderately sized rodents, with a head-body length of 10 to 13 centimetres (3.9 to 5.1 in), a tail 8 to 11 centimetres (3.1 to 4.3 in) long, and a body weight averaging 40 grams (1.4 oz). Unlike all other fish-eating rats of the genus Neusticomys, it has dull greyish-black fur, consisting of a thick, velvety underfur and occasional dark guard hairs. The fur is uniform over most of the body, and, unlike in many other rats, remains thick over the tail. However, the toes of all four feet are white, and some individuals have white spots on the upper body, the tip of the tail, or on the chest region. The ears are unusually large for a member of its tribe, and are visible above the thick fur.[2]
Like other ichthyomyine rodents, montane fish-eating rats have feet adapted for swimming in water. However, the adaptations are less extreme in this species than in most others; for example, the feet are narrower, and the fringe of stiff hairs around the toes is less well developed. A short web, not quite reaching the first joint, connects the second and third and the third and fourth toes.[3] Females have six teats, one pair each on the chest, abdominal, and inguinal regions.[2]
Montane fish-eating rats are found only in the mountains of northern Ecuador and western Colombia, where they inhabit fast moving streams flowing through cloud forests. They are found at elevations between 1,800 and 3,754 metres (5,906 and 12,316 ft). There are no recognised subspecies.[2]
Montane fish-eating rats are either crepuscular or nocturnal. Despite their common name, they have never been observed to eat fish. Instead, the stomach contents of the few specimens examined consist solely of freshwater invertebrates, such as scirtid water beetles, crane flies, mayflies, stoneflies, and caddisflies. Little else is known of their habits and biology, because only 47 specimens have ever been collected.[2] One of these specimens, collected in May, early in the wet season, was pregnant, but it is unknown whether or not there is a true breeding season.[3]
The montane fish-eating rat (Neusticomys monticolus) is a species of semiaquatic rodent in the family Cricetidae. It inhabits the Andes Mountains of Colombia and Ecuador.
