Robinson's miniature pouch rat
| Robinson's miniature pouch rat | ||||||||||||
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Robinson's dwarf bag rat ( Marmosa robinsoni ) |
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| Scientific name | ||||||||||||
| Marmosa robinsoni | ||||||||||||
| Bangs , 1898 |
Robinson's pygmy pouch rat ( Marmosa robinsoni ) is a species of marsupial that is found in Panama, in northern and western Colombia, in Venezuela north of the Orinoco and on the islands of Isla del Rey and Taboga in the Gulf of Panama and on Isla Margarita , Trinidad , Tobago and Grenada in the Caribbean occurs.
description
The animals reach a head trunk length of 11.1 to 21.8 (males) or 8.3 to 15.5 cm (females), have a length of 14.5 to 21.5 or 10.1 to 19.5 cm Tail and reach a weight of 39 to 110 or 39 to 110 (males) and 16 to 72 g (females). So the males are larger than the females and usually have a larger skull as well. In Venezuela it was found that animals from agricultural areas and from human-impaired forests are larger than those from undisturbed forests. The back fur of the animals and the top of the head are dark yellow-brown or gray-brown in color, the sides of the body are lighter. The sides of the head are lighter than the top of the head. There are blackish-brown or dark brown circles around the eyes, sometimes reaching to the bases of the ears. The eyes are black. There is no central dark line on the muzzle. The belly is yellowish or cream-colored and sometimes shows a dark median stripe. The front paws are orange to brown, the hind feet are whitish, cream-colored or orange-colored. The 10 or 20% of the tail close to the body are hairy. The hairless section of the tail is yellowish to dark brown and slightly lighter on the underside than on the top and sides. Females do not have a pouch. The number of teats is 13, six are on the sides and one is in the middle. The karyotype consists of a chromosome set of 2n = 14 chromosomes (FN = 24).
Habitat and way of life
Robinson's pygmy bag rat lives from sea level up to heights of 2600 meters in lowland rainforests, in moist mountain forests, in dry forests, in mangrove forests and in savannas. It is nocturnal and seems to prefer secondary forests and other human-impaired habitats. Their diet has not yet been studied in detail. One can assume, however, that like other dwarf sacred rats, it mainly eats insects and, secondarily, fruits. Robinson's pygmy pouch-rat lives on the ground and climbs in the bush. When in danger, it prefers to flee into bushes or climb low trees. In Venezuela a population density of 25 to 425 specimens per km² has been established. In the dry season the average size of the territory used by an individual is 0.36 ha. In the rainy season it shrinks to 0.17 ha due to flooding. The formation of social hierarchies has been observed in animals kept in human care.
Reproduction
For reproduction, the female builds a nest in tree hollows or in abandoned bird nests. Females that are not ready to reproduce react to the approach of males with negative noises and bites. Females ready to mate behave passively or become active themselves by sniffing males. Two to 19 young animals are usually born in the rainy season after a gestation period of two weeks. They are then about 8 to 12 mm long. The young animals are initially firmly attached to a teat and are carried around by the mother animal during all of its activities. After 30 days, they separate from the teats for the first time and remain in the nest. The fur begins to grow at around 29 days of age and is fully developed at around 47 days of age. The young open their eyes at the age of 39 or 40 days and then start to leave the nest with their mother or alone. They begin to eat solid foods by 50 to 58 days of age and are weaned by around 65 days of age. The length of the rainy season allows for two consecutive births in most cases. Males reach sexual maturity at one year of age; females experience their first oestrus lasting two to three days at an age of 265 to 275 days.
status
Robinson's pygmy pouch rat is considered harmless. It has a wide range, is common, and occurs in several protected areas.
supporting documents
- ↑ a b c d e Diego Astúa: Family Didelphidae (Opossums). in Don E. Wilson , Russell A. Mittermeier : Handbook of the Mammals of the World - Volume 5. Monotremes and Marsupials. Lynx Editions, 2015, ISBN 978-84-96553-99-6 . Page 139.
- ↑ Marmosa robin soni in the endangered Red List species the IUCN 2016 Posted by: Perez-Hernandez, R., 2015. Retrieved on 4 February of 2019.