Phyllotis amicusfriendly leaf-eared mouse

Geographic Range

Phyllotis amicus is found exclusively on the coast and lower Pacific slopes of western Peru stretching from Piura to Arequipa. ("Phyllotis amicus", 2016)


Phyllotis amicus occurs in xeric, arid environments wish sparse vegetative cover. The habitat varies from dry, rocky slopes with boulders to sandy areas with Capparis bushes and mesquite to steep rocky hillsides with scattered shrub and cacti cover. The friendly leaf-eared mouse has also been found to occur in dry slopes dominated by boulders and tola bushes. The elevation which P. amicus occurs ranges from 50-2,100 m. (Arana, et al., 2002; Pearson, 1972)

A 2002 study discovered that P. amicus can be found in a unique seasonal habitat on the central coast of Peru , 105 km north of Lima, the Lomas of Lachay. Mean annual precipitation in this area is .5mm. This habitat is harsh, xeric environment. (Arana, et al., 2002)

  • Range elevation
    50 to 2,100 m
    164.04 to ft

Physical Description

Phyllotis amicus is characterized by small body size, ears as long as or longer than hind feet, short molar toothrows (3.5-4.2mm), and short hind feet. The friendly leaf-eared mouse typically has short brown fur and a naked tail. The underbelly and tail are pure white. Specimens at the costal, Northern-most part of its range are small and brightly colored. As the range progresses south and inland, specimens become larger and duller. The interorbital region of P. amicus is broad and flat and the edges are frequently square or sharp. The skull also presents large and globular auditory bullae. This species has opisthodont upper incisors and a conspicuous development of second out entrant angle on M2. (Patton, 2015)

The range of Phyllotis amicus comes in contact with P. limatus, P. andium, P. definitus, and P. gerbillus. P. amicus is much smaller than P. definitus and P. limatus and has shorter fur, a more naked tail, smaller teeth, opisthodont incisors, and a more conspicuous development of two outer entrant angles of M2. P. amicus can be distinguished from P. gerbillus with its pure white belly and tail, and smaller ears. P. amicus is smaller, slightly paler, has a more conspicuous development of second out entrant angle on M2, and ears proportionally larger than P. andium. (Patton, 2015)

  • Sexual Dimorphism
  • sexes alike
  • Average mass
    20.8 g
    0.73 oz


There is little available information on the mating systems of Phyllotis amicus.

The species Phyllotis amicus displays no seasonal reproductive activity and has been found to reproduce year-round. Lack of seasonal reproduction may be tied to the feeding habits of the species. It is possible that P. amicus has a lower dependence on availability of vegetation, unlike the other Phyllotis species, because they have been found to consume more insects than any other species of Phyllotis. (Arana, et al., 2002)

Friendly leaf-eared mice have a gestation period of 24 days and have a litter size of 1-3. A smaller litter size provides greater potential survivorship in a harsh xeric environment than a large litter. A 2002 study found a significant difference between weight and age with different litter sizes of P. amicus which indicated a relationship between weight and litter size. Young from a litter of 2 were found to get heavier and gain weight faster than young from a larger litter. The short duration of P. amicus pregnancy suggests that a female can reproduce many times in one year. (Arana, et al., 2002)

There is not much documentation about what age Phyllotis amicus becomes sexually mature, however in captivity it was found that females less than 7 months old were not reproductive. (Arana, et al., 2002)

Young P. amicus are weaned at 30 days of age. The mean weight at weaning is 14.4g(+-)2.6g. Young reach their mean weight of 20.8g(+-) 4.7g at 2-3 months of age. (Arana, et al., 2002)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Breeding season
    Friendly leaf-eared mice show no seasonal reproduction and can reproduce at any time of the year.
  • Range number of offspring
    1 to 3
  • Average gestation period
    24 days
  • Average weaning age
    30 days
  • Range age at sexual or reproductive maturity (female)
    7 (low) months

There is little known information on the parental investment of Phyllotis amicus. In captivity, females raise their young without the presence of the father. Young are weaned at 30 days of age. (Arana, et al., 2002)

  • Parental Investment
  • female parental care
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female


There is little available information regarding the lifespan of Phyllotis amicus.


Phyllotis amicus is a nocturnal species. Not much is known about its social behavior, however it is thought that the species could have a social type of spatial organization due to its aggregated distribution throughout the year. This may be the result of a limiting factor such as shelter or substrate. (Arana, et al., 2002)

Home Range

There is little information known about the home range of Phyllotis amicus however in a 2002 study it was found that P. amicus moved 22.8-77.8m per month with a mean movement of 44.5m. (Arana, et al., 2002)

Communication and Perception

Little is known about the communication and perception of Phyllotis amicus

Food Habits

Although limited information is available on the diet of Phyllotis amicus, it is known that this species is omnivorous and consumes more insects than other Phyllotis species. The feeding habits of P. amicus imply that this species may depend less on availability of vegetation and as a consequence, allows this species to reproduce without seasonality. In captivity, P. amicus consumes fresh carrots, lettuce, sweet potato, sprouted wheat, and corn. P. amicus has been found to not drink water in captivity which implies that the species has the capacity to survive through a drought. (Arana, et al., 2002)

  • Animal Foods
  • insects
  • Plant Foods
  • leaves
  • roots and tubers
  • seeds, grains, and nuts


Little information is known about the depredation of Phyllotis amicus. The species P. amicus does, however, occur in similar areas to another Phyllotis species, Phyllotis darwini. Burrowing owls (Athene cunicularia), barn owls (Tyto alba), and Culpeo foxes (Lycalopex culpaeus) are known predators of P. darwini. (Previtali, et al., 2009)

Ecosystem Roles

Little is known about the ecosystem role of Phyllotis amicus. The friendly leaf eared mouse is predator to insects in its region and potentially prey to burrowing owls (Athene cunicularia), barn owls (Tyto alba), and Culpeo foxes (Lycalopex culpaeus). (Arana, et al., 2002; Previtali, et al., 2009)

Economic Importance for Humans: Positive

There is little known information on the positive economic importance of Phyllotis amicus to humans, however this species is easy to keep in captivity which could imply their use for research. (Arana, et al., 2002)

Economic Importance for Humans: Negative

There is little known information on the negative economic importance of Phyllotis amicus to humans however, this species does consume both grains and insects which could impact farming within this species' range. (Arana, et al., 2002)

Conservation Status

Phyllotis amicus is listed as a species of Least Concern on the ICUN Red List and is not listed on the US Federal List, CITES, or the State of Michigan List. The friendly leaf-eared mouse has a wide distribution, with a population density of 0 to 12 individuals per hectare and occurs in a number of protected areas. (Arana, et al., 2002)


Margaret Braun (author), University of Wisconsin Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Tanya Dewey (editor), University of Michigan-Ann Arbor.



living in the southern part of the New World. In other words, Central and South America.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.


animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females


An animal that eats mainly insects or spiders.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


an animal that mainly eats all kinds of things, including plants and animals


reproduction that includes combining the genetic contribution of two individuals, a male and a female


uses touch to communicate


Living on the ground.


2016. "Phyllotis amicus" (On-line). The ICUN Red List of Threatened Species. Accessed August 20, 2016 at

Arana, M., O. Ramirez, S. Santa Maria, C. Kunimoto, R. Velarde, C. De La Cruz, M. Luisa Ruiz. 2002. Population density and reproduction of two Peruvian leaf-eared mice (Phyllotis spp.). Revista Chilena de Historia Natural, 75: 751-756.

Patton, J. 2015. Mammals of South America, Volume 2: Rodents. Chicago, Illinois, USA: University of Chicago Press.

Pearson, O. 1972. New informtion on ranges and relationships within the rodent genus Phyllotis in Peru and Ecuador. Journal of Mammalogy, 53: 677-686.

Pizzimenti, J., R. De Salle. 1980. Dietary and morphometric variation in some Peruvian rodent communities: the effect of feeding strategy on evolution. Biological Journal of the Linnean Society, 13: 263-285.

Previtali, M., M. Lima, P. Meserve, D. Kelt, J. Gutierrez. 2009. Population dynamics of two sympatric rodents in a variable environment: rainfall, resource availability, and predation. Ecology, 90/7: 1996-2006.