Tres Marias island mouse

The Tres Marias deer mouse ( Peromyscus madrensis ) is a type of Weißfußmäuse, which is endemic to the belonging to Mexico Marias Islands.

Appearance

Since the Tres Marias deer mouse is the only species of its genus on the Marias Islands, there can not be confused with other species.

The coat is yellow-brown on the back side, white on the ventral side. On the rear part of the back a dark band, but that stands out only slightly from the color runs. On the chest there is often, but not always, a pink stain. The tail is in the front two -thirds in two colors: at the top of dark brown, light brown at the base; also this color difference is, however, unclear. In the last third he is uniformly dark brown.

The head -body length is 20 to 25 cm, the tail is 10 to 13 cm long.

Dissemination

The Tres Marias deer mouse lives on all four islands of the Marias Islands: María Madre Isla María Magdalena, María Cleofas and San Juanito. In María Madre, the only populated of the four islands, it was supplanted by the common house rat in the deciduous forests in the hilly interior of the island. In María Cleofas, where there are no rats, the species is exceedingly common and lives in all sorts of habitats, from forests to the coast. In María Magdalena, the Tres Marias deer mouse was not seen after introduction of the black rat. On the small island of San Juanito, they should be very common.

The Tres Marias deer mouse probably came in the Pleistocene to the islands. According to one theory, the islands to the mainland were connected and were only separated by the Polkappenschmelze after the last ice age from Mexico. Another theory assumes that the mice on flotsam reached the islands.

System

As a next of kin of the Tres Marias deer mouse Peromyscus Peromyscus boylii simulus and are suspected. Long it was classified as a subspecies of boylii and raised only in 1977 at the species level.

Subspecies are not distinguished. However, it was found that the specimens on María Cleofas on average are larger than on María Madre.

Relation to man

Previously, the Tres Marias deer mouse was very common on all four islands. The introduction of rats in many places has forced the mice in inaccessible regions. Also entrained deer and goats have changed the vegetation and may also be responsible for the population decline. The IUCN classified the species as endangered.

Swell

• Sergio Álvarez - Castañeda Ticul, Lia Méndez: Peromyscus madrensis. In: Mammalian Species. No 774, 2005, pp. 1-3.