Pemberton's Deer Mouse (Peromyscus pembertoni) lived on San Pedro Nolasco Island

San Pedro Nolasco Island

San Pedro Nolasco Island, sometimes called Seal Island, is a small and rugged Mexican island in the Gulf of California. It is 4.2 km long by 1 km wide, and lies 15 km from the nearest point of the Mexican coast and about 28 km west of the resort town of San Carlos on the coast of the Sonoran Desert...

 (27.96749°N 111.37845°W) in the Gulf of California

Gulf of California

The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...

. The last 12 specimens were collected on 26 December 1931.

Etymology

The generic name comes from the Greek "pero" = "boots", "mys" meaning "mouse", hence the "mouse with boots", referring to the white feet.

General information

Peromyscus species, also known as deer mice, are common North American mammals. They tend to occur in range from Alaska to Central America in many different habitats. For the fact that they are so abundant in nature, these mice constitute a large component of the nearctic ecosystems. These mice have also been of very great importance to the scientific esearch, both the wild type and the genetically variant have been used for laboratory researches. They do differ from the house mouse and the rats, because they are not closely related to these species.

Peromyscus are very cold-tolerant species, they do prefer to live and survive in temperatures between 22–25°C. They are usually sexually mature by 55 days of age. Gestation is 23 days, except in lactating females where it is delayed by 4–6 days to 28 or 30 days. Peromyscus breed in mated pairs.

Most species have potential life spans of 4–5 years. Mice of the genus Peromyscus range in adult size from 15 g to 150 g. They mostly feed on seeds and berries which constitute about 75% of the diet and about 25% is other animal material. A few are more insectivorous.

Habitat

This species is poorly known. The only island that supported two different species of Peromyscus - P. pembertoni and P. boylii - was San Pedro Nolasco. Besides these two species no other mammals occurred on the island. They were found or collected on a steep hill covered with grass on the eastern side of the island. The dominant plants found there were Tree torote, pitayita, liga, Adam's tree, leather plant, fishhook cactus, malva rosa, chain fruit cholla, cardon, slipper plant, jojoba, and organpipe cactus.

Physical description

Peromyscus pembertoni is a medium-sized Peromyscus. No significant sexual dimorphism is evident. The tail is usually longer than the head and body is bicolored. Well haired, and tufted at the end. The hind foot is small and similar in length to the ear but sometimes longer. Skull is medium-sized and auditory bullae are not greatly inflated. Upperparts of pelage are medium brown; sides lighter brown with a broad orange lateral line extending from cheek to hindquarters; underparts whitish; ankles dusky gray; and feet whitish below ankle.

Reproduction

The social behaviour of P. pembertoni has not been very well studied or investigated. Very little information is available on the mating system. Breeding in P. pembertoni occurs throughout most of the year, although the majority of young are born in spring and early summer. Breeding may cease during winter months.

Communication and perception

Like other Peromyscus species, they have keen eyesight and vision and extensively use chemical cues in communication.

Predation

P. pembertoni escapes predation through their nocturnal and secretive habits. They are important prey items for many predatory mammals such as preys of birds, snakes, foxes, owls, and hawks.

Life span

The longevity of Peromyscus is typically short with few living more than one year or less under natural conditions.