Koprowski, J. L., N. Ramos, B. S. Pasch, and C. A. Zugmeyer. 2006. Observations on the ecology of the endemic Mearns's squirrel (Tamiasciurus mearnsi). The Southwestern Naturalist 51(3): 426-430.

thackerk1 — Mon, 22 Jul 2019 23:06:13 +0000

Authors

John L. Koprowski

Nicolás Ramos

Bret S. Pasch

Claire A. Zugmeyer

Mearns’s squirrel (Tamiasciurus mearnsi) is an endemic species of the montane forest of the Sierra de San Pedro Mártir in Baja California. Despite having been described for the first time in 1893 and a listing as threatened by Mexican authorities, no information is available on the ecology of this southernmost Tamiasciurus. We observed the ecology of Mearns’s squirrels during 2004 and 2005. Mearns’s squirrel apparently does not form larderhoards, known as middens, or leaf nests commonly built by other members of this genus. We observed Mearns’s squirrels to feed heavily on tree seeds and fungi. We noted males with scrotal testes and a female in estrus in late spring. We did not observe eastern gray squirrels (Sciurus carolinensis), introduced to the western Sierra in 1946, within the areas that we searched for T. mearnsi. Mearns’s squirrels might possess unique adaptations for their persistence in the dry, open forest of the Sierra de San Pedro Mártir.

Additional Information

OBSERVATIONS ON THE ECOLOGY OF THE ENDEMIC MEARNS’S SQUIRREL (TAMIASCIURUS MEARNSI)

Date of publication:

2006

Topics

Mearn’s squirrel

endemic species

adaptations

montane forest

Sierra de San Pedro Mártir

Tamiasciurus mearnsi (Rodentia: Sciuridae)

thackerk1 — Mon, 22 Jul 2019 21:30:50 +0000

Authors

John L. Koprowski

Michael A. Steele

Nicolás Ramos-Lara

Tamiasciurus mearnsi (Townsend, 1897) is a small-sized tree squirrel commonly called Mearns’s squirrel. One of 3 species that comprise the genus Tamiasciurus, T. mearnsi, is endemic to the Sierra de San Pedro Mártir in Baja California, Mexico; it is considered rare and occurs only at low densities. T. mearnsi is federally listed as “Threatened” in Mexico and is also included in the International Union for the Conservation of Nature and Natural Resources Red List of Threatened Species as “Endangered.” The introduction of the eastern gray squirrel (Sciurus carolinensis) may be a serious threat to this relict species.