Four-eyed gray pouch rat
| Four-eyed gray pouch rat | ||||||||||||
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Four-eyed gray rat, image from |
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| Philander opossum | ||||||||||||
| ( Linnaeus , 1758) |
The gray four-eyed rat ( Philander opossum ) is a species of marsupial from the family of the opossum rats (Didelphidae). It occurs in the rainforest in the three Guyanas and in the northern and eastern Brazilian Amazon basin .
description
The gray four-eyed rat reaches a head body length of 20 to 33 cm, has a 19.5 to 33.5 cm long tail and can reach a weight of 200 to 675 g. Specimens kept in human care weighed up to 1.5 kg. The fur on the back of the gray four-eyed rat is light to dark gray. The belly is light, yellowish or creamy white. The fur is dense, short and soft. The head has the same color as the back and shows the characteristic bright spots above the eyes, which give the species its name. The ears are relatively large and hairless. Females have a fully formed pouch with the opening in the front and containing a total of seven teats, one in the center and three on each side. The karyotype consists of a chromosome set of 2n = 22 chromosomes (FN = 29). The four-eyed gray rat is similar to Philander canus . Both are gray on the back with pale hind feet. Philander canus is on average much smaller. About half of the tail of the gray four-eyed rat is colored white. With Philander canus it is the last quarter or less. Other differences concern the morphometry of the skull.
Way of life
The four-eyed gray bag rat occurs in primary forests, secondary forests, gallery forests and in gardens, where it prefers humid habitats. It is considered nocturnal, but in Suriname the animals were also observed during the day. In a secondary forest in French Guiana, a population density of 85 to 180 specimens per square kilometer has been determined, depending on the season. Gray four-eyed pouch rats are omnivores and feed on fruits, worms, insects, arachnids , snails, crustaceans and frogs. Fruits make up about half of their diet. It is mainly eaten fruits with plenty of pulp, high water content and soft skin. Small seeds are eaten with them, larger ones are left behind. For reproduction, the females build round nests of leaves in tree hollows, forks of branches, hollowed fallen trunks between banana or palm fronds, or under house roofs. The nests have a diameter of about 30 cm. Newborns weigh about 9 g at birth, grow rapidly, and weigh 50 to 75 g at the time of weaning at 69 to 75 days of age. On average, 4 to 5 young are born. In undisturbed primary forests the animals can reproduce all year round, in secondary forests there are fewer births during the dry season. In French Guiana it has been observed that females give birth two to four times a year and that the interval between two births is around 90 days. Females become sexually mature at around 6 to 7 months of age, while males are around 7 months old. In the wild, the four-eyed rat is about 2.5 years old.
Systematics
The gray four-eyed rat was first described in 1758 by Carl von Linné , the founder of binary nomenclature and modern biological taxonomy, under the name Didelphis opossum . The genus Philander was introduced four years later by the French zoologist Mathurin-Jacques Brisson . Terra typica for Philander opossum is Suriname . Between 1899 and 1913 other four-eye pouch rat forms were described, which were assigned to Philander opossum as a subspecies, and for a long time Philander opossum was the only four-eye pouch rat species widespread in South and Central America. In a revision of the four-eye sac rats published in 2018, the subspecies of the gray four-eye rat living in Central America and northwestern South America became independent species ( Philander canus , Philander melanurus , Philander pallidus ) and those in the western Brazilian Amazon basin, as well as in the eastern lowlands of Ecuador and Peru occurring four-eye bag rats were described as a new species under the name Philander pebas . Thus, the gray four-eyed rat is now monotypical .
Danger
Because of their widespread distribution, their frequency, their tolerance to changes in their environment and their occurrence in various protected areas, the four-eyed rat is considered safe.
supporting documents
- ^ A b c Robert S. Voss, Juan F. Díaz-Nieto and Sharon A. Jansa. 2018. A Revision of Philander (Marsupialia: Didelphidae), Part 1: P. quica, P. canus, and A New Species from Amazonia. American Museum Novitates. Number 3891; 1-70. DOI: 10.1206 / 3891.1 (page 167)
- ↑ a b c Diego Astúa: Family Didelphidae (Opossums). Pages 485-486 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