House shrew pouch rat
| House shrew pouch rat | ||||||||||||
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House shrew pouch rat ( Monodelphis domestica ) |
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| Scientific name | ||||||||||||
| Monodelphis domestica | ||||||||||||
| ( Wagner , 1842) |
The house shrew rat ( Monodelphis domestica ) lives in central South America , south of the Amazon basin in a broad strip that extends from eastern Brazil to eastern Bolivia , the north and center of Paraguay and the Argentine province of Formosa .
description
The animals reach a head trunk length of 12.3 to 17.9 cm and have a 4.6 to 9.6 cm long tail and reach a weight of 58 to 110 g. Specimens kept in captivity, the domestic shrew pouch-rat, are used as test animals, and with a head body length of 20 cm and a maximum weight of 150 g, they can become significantly larger. Males grow larger than females, who stop growing when they reach sexual maturity, while the males continue to grow afterwards. The males' skulls are also larger. From all other shrew pouch rats with the exception of the Santa Rosa shrew pouch rat ( M. sanctaerosae ), the house shrew pouch rat differs in its predominantly gray to gray-brown coloration. Only the belly is lighter with a slightly yellowish or reddish tint. The paws are pink or whitish. The fur is short, dense and soft. Only the base of the tail is hairy. Females do not have a pouch. The number of teats is 13, six each on the right and left and one in the middle. The domestic shrew pouch rat has a chromosome set of 2n = 18 chromosomes with a variable number of arms (fundamental number, FN) of 20, 22, 24, 28 or 30.
Habitat and way of life
The house shrew pouch rat occurs in dry areas such as the Brazilian Cerrado , in the semi-arid Caatinga , in various thorn bush savannahs , in the Chaco as well as in moist habitats, e.g. B. in the Pantanal or on the southern edge of the Amazon basin. They are mainly found in regions with relatively open vegetation, but not in areas only covered with grass. The house shrew pouch-rat lives solitary. Social interactions with conspecifics are limited to the mating season. It lives mainly on the ground, but has also been observed climbing bushes up to heights of three meters. While the other shrew pouch rats are more active at twilight, the house shrew pouch rats are nocturnal. Their main activity time is one to three hours after sunset.
nutrition
The house-shrew-pouch-rat feeds mainly on insects, also on other invertebrates, on small vertebrates, carrion and fruits. Seeds of the cactus species Cipocereus minensis were found in the faeces of the animals . Scorpions are preyed on by pressing them to the ground with their front paws and then severing the poison sting at the end of their tail with a quick bite. Specimens kept in captivity have also killed and eaten lizards and snakes whose weight was 75% of the weight of the domestic shrew pouch rat and in the wild it was observed that vesper mice ( Calomys ) were killed and eaten with a third of the weight of the opossum.
Reproduction
For reproduction, the females build nests in rock caves and rock niches. Grass, leaves, bark, snake skins, paper, scraps of fabric and plastic are used for construction. The material for building the nest is collected with the front paws, then pushed under the belly to the tail, wrapped around it and carried to the nest. As a rule, 6 to 11 pups are born after a gestation period of around two weeks, with younger females generally giving birth to fewer pups than older ones. In exceptional cases, a litter can contain up to 16 young animals, but only those that can get a place on a teat survive. The young animals are 10 mm long (head trunk length) at birth and weigh 0.1 g. They remain sucked onto the teats for about two weeks and are weaned at eight weeks of age. The first fur approaches appear after 18 to 21 days and the young animals open their eyes for the first time when they are 28 to 35 days old. They reach sexual maturity at five to seven months of age. In human care, the animals can reach an age of 36 to 49 months.
Systematics
The author of the first description of the domestic shrew pouch rat is the German zoologist Johann Andreas Wagner , who described it in 1842 under the name Didelphis domestica . Today it belongs to the genus Monodelphis , with over 20 species one of the most species-rich genus of the opossum. There is no distinction between subspecies. The latest phylogenetic studies, in which the mitochondrial DNA of various shrew pouch rats were compared with one another, show that the species consists of two clades, one lives in the west and in the middle of the range in the Pantanal wetland and in the semi-arid savannas of the Cerrado and the second in the east in the semi-arid Caatinga . Since the Terra typica of Monodelphis domestica is located near Cuiabá in the west of the distribution area, a new name would have to be found for the population in the dry northeast if the species were split up.
status
The domestic shrew pouch rat is considered safe by the IUCN . It has a large distribution area, is also found in some protected areas and changes in its habitat that are not too extensive by humans are usually tolerated.
supporting documents
- ↑ a b c d e f g 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 151 and 152.
- ↑ Silvia Eliza Pavan, Rogerio Vieira Rossi, Horacio Schneider: Species diversity in the Monodelphis brevicaudata complex (Didelphimorphia: Didelphidae) inferred from molecular and morphological data, with the description of a new species. Zoological Journal of the Linnean Society, Volume 165, Issue 1, May 2012, Pages 190-223, doi: 10.1111 / j.1096-3642.2011.00791.x
- ↑ Monodelphis domestica in the endangered Red List species the IUCN 2016 Posted by: Flores, D. & de la Sancha, N., 2016. Accessed January 21, 2020th