Caenolestes condorensis

Geographic Range

Andean shrew opossums ( Caenolestes condorensis ) are a newly discovered species. They are currently only known to occur in the eastern slopes of the Ecuadorian Andes, within the Cordillera del Condor region. However, it is likely that this species is also found within the same environment in Peru, although it has not yet been discovered there.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Andean shrew opossums have only been found within the Cordillera del Condor region of the Ecuadorian Andes Mountains. Compared to other regions within the Andes, Cordillera del Condor has an extremely wet environment. This area is unique in that it almost never experiences drought and has almost constant precipitation in the form of both rain and cloud condensation. In a day, this region may experience up to a couple of hours of sunlight. Andean shrew opossums have a similar habitat preference to their close relatives, gray-bellied shrew opossums ( Caenolestes caniventer ); both species are found in montane or sub-tropical forests. Unlike another close relative, silky shrew opossums ( Caenolestes fuliginosus ), both species are found in relatively lower elevations. Andean shrew opossums are likely found near vegetation less than 1.5 meters in height.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• mountains mountains

Physical Description

Andean shrew opossums are marsupials; they are somewhat shrew-like in appearance, with elongated faces. Andean shrew opossums are the largest members of the genus Caenolestes . They have brownish-gray fur covering most of their body; their underside is a more solid brown in comparison. Their fur is about 10 mm in length and they have a pink nose and white whiskers. Andean shrew opossums have an average total body length of 256 mm, including a tail length of 127 mm and weigh about 48 grams. However, all of these estimates are based on the only two individuals of this species that have been captured and described. Otherwise, Andean shrew opossums are very similar in appearance to their relative, gray-bellied shrew opossums ( Caenolestes caniventer ). Both species are relatively robust and have similar coarse fur; however, they can be distinguished by the relatively larger body size and upper canines of Andean shrew opossums.

In general, members of family Caenolestidae can be distinguished from other marsupial groups by their unique dentition. They have a reduced number of insicors and their lower middle incisors are large and have a forward slope. The dental formula for genus Caenolestes is: I 4/3, C 1/1, P 3/3, M 4/4, 46 teeth total. Their tail is long, about as long as their body, and appears rat-like and hairless, although it is covered in white fur. While their tail is not prehensile, it is used for support while they climb. Shrew opossums have short robust limbs, each containing 5 digits; their middle 3 digits are shorter than the outside 2. Their humeri are extremely heavy; in comparison, their femurs are relatively slender. Members of family Caenolestidae have unusual lip flaps, which may function as a method of preventing debris from interfering with their whiskers or they may help prevent ingestion of unwanted debris. Similar to other marsupials, Caenolestid females have 2 uteri and 2 vaginas. Members of genus Caenolestes lack a pouch but do have 4 mammae, 2 on either side of their abdomen. All Caenolestids show sexual dimorphism, with adult males larger than adult females.

Common shrew opossums ( Caenolestes obscurus ), a close relative of Andean shrew opossums, show evidence of a low metabolic rate, based on their body temperature (35.4° C), their body weight (about 40 g), their cool habitat and their thick fur coat. This species shows no evidence of entering torpor.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

There is currently little information available regarding the mating system of Andean shrew opossums.

Female Andean shrew opossums lack a marsupium; however, immature individuals may have an undeveloped fold of skin that they lose before reaching maturity. Females have 4 mammae available for their young to nurse. Evidence suggests that Caenolestid females have the same number of ova as mammae, unlike family Didelphidae . In support of that notion, a female was found pregnant with 3 embryos, 2 in the right uterus and 1 in the left. These animals likely have one annual breeding season from February to August.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

No information is currently available regarding this species.

Lifespan/Longevity

There is currently no information on the longevity of Andean shrew opossums.

Behavior

Members of genus Caenolestes are solitary; they are primarily active during the early evening and at night. They are terrestrial, but they are also adept climbers. During the day, these animals stay in tunnels under tree roots. When they are active, they travel through paths in dense vegetation.

• Key Behaviors
• terricolous
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• solitary solitary

Home Range

There is currently no information available about the individual home range of Andean shrew opossums.

Communication and Perception

Members of family Caenolestidae have very small eyes and poor eyesight. Their unusual lip flaps have the hypothesized function of clearing debris from their sensitive vibrissae, but they may merely function as a method of preventing the ingestion of unwanted debris. Their somewhat primitive brains have enlarged olfactory bulbs, which could indicate an enhanced sense of smell. When they are startled they attempt to hide and they hiss when cornered. Caenolestids are not noted for frequent production of sound, however, captive individuals may make several sounds including whistles, bird-like screams, rat-like squeaks and drawing air through their incisors.

• Communication Channels
• tactile tactile
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Members of genus Caenolestes are opportunistic feeders. Their stomach contents indicate that they are primarily insectivores. Ingested invertebrates include beetles , crickets , butterfly larvae, centipedes , grasshoppers , spiders , and earthworms . A smaller proportion of their diet is composed of vegetation, fruit and small vertebrates including juvenile mice . They forage for food in moss and leaf litter. When they find a food item, they manipulate and consume it with their forepaws, from a semi-seated position. As Caenolestids shear their food with their incisors, they produce a clicking sound.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore

• Animal Foods
• mammals
• insects
• terrestrial non-insect arthropods
• terrestrial worms

• Plant Foods
• leaves
• fruit

Predation

There is currently little information regarding the predation of Andean shrew opossums. However, there are several carnivores known to inhabit a similar range and prey upon small mammals , such predators include Andean Mountain cats ( Leopardus jacobita ), pampas cats ( Leopardus colocolo ), culpeo foxes ( Lycalopex culpaeus ) and cougars ( puma concolor ), among others.

Ecosystem Roles

Andean shrew opossums have an insectivorous diet. Likewise, Caenolestids are often plagued by lice of the genus Cummingsia . Interestingly, Australian marsupials are also affected by similar lice , related to the family level. Caenolestids may also become infested with South American hard ticks ( Ixodes jonesae ).

Economic Importance for Humans: Positive

Due to their human-inaccessible habitat, there has been very little study of these animals. Likewise, there has been very little interaction between human and shrew opossum populations. They may, however, serve as a control of insect populations.

Economic Importance for Humans: Negative

There are no known negative effects of Andean shrew opossums on human populations.

Conservation Status

Andean shrew opossums are currently listed as vulnerable on the IUCN Red List of Threatened Species. However, the reason for this listing is due to their limited range. Currently, this species has only been found in the Cordillera del Condor region of the Ecuadorian Andes. It is likely that Andean shrew opossums may also extend into the Peruvian region as well.

Additional Links

Encyclopedia of Life

Contributors

Leila Siciliano Martina (author), Texas State University.

References

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