Female-biased sexual size dimorphism: ontogeny, seasonality, and fecundity of the cliff chipmunk (Tamias dorsalis)

thackerk1 — Mon, 22 Jul 2019 21:28:06 +0000

Authors

Allyssa L. Kilanowski

John L. Koprowski

Female-biased sexual dimorphism is uncommon in mammals and is usually attributed to increased fecundity of large females. Moreover, sexual dimorphism is usually described for adults, and the ontogeny of sex differences is poorly documented. We studied cliff chipmunks (Tamias dorsalis), a small mammal with female-biased sexual dimorphism, to describe development of sexual dimorphism in juveniles and to measure sexual dimorphism and seasonal body mass in adults. To test the fecundity hypothesis, we compared body mass of females to litter size and body mass of offspring. Juveniles were not sexually dimorphic at emergence from the nest and did not differ in body mass 2 months after emergence. Adult chipmunks maintained a relatively stable body mass in March–October with females consistently larger than males. Maternal mass did not have an effect on litter size or mass of juveniles. Because females were consistently larger than males, the ontogeny of sexual dimorphism may provide insights into selection pressures that lead to female-biased sexual dimorphism.

Additional Information

Journal of Mammalogy

Date of publication:

2016

Topics

body mass

cliff chipmunk

litter size

small mammal

female-biased sexual dimorphism

Arizona

Research Categories

Natural History Population Ecology Sky Islands

Cudworth, N. L., and J. L. Koprowski. 2010. First record of range extension of the cliff chipmunk (Tamias dorsalis) into the Huachuca Mountians. Western North American Naturalist 70:418-420.

thackerk1 — Mon, 24 Jun 2019 23:27:52 +0000

Authors

Nichole L. Cudworth

John L. Koprowski

Chipmunks are widely distributed throughout the mountain ranges of Arizona. However, no living chipmunks are known from the Huachuca Mountains despite the availability of favorable habitat. Based upon pelage characteristics of captured individuals, we provide the first report of a breeding population of cliff chipmunks (Tamias dorsalis) in the Huachuca Mountains and discuss possible mechanisms of their arrival.

Additional Information

First Record of a Range Extension of the Cliff Chipmunk (Tamias dorsalis) into the Huachuca Mountains

Date of publication:

2010

Topics

cliff chipmunk

Huachuca Mountains

distribution

conservation.arizona.edu - cliff chipmunk

Female-biased sexual size dimorphism: ontogeny, seasonality, and fecundity of the cliff chipmunk (Tamias dorsalis)

Authors

Additional Information

Topics

Research Categories

Cudworth, N. L., and J. L. Koprowski. 2010. First record of range extension of the cliff chipmunk (Tamias dorsalis) into the Huachuca Mountians. Western North American Naturalist 70:418-420.

Authors

Additional Information

Topics