conservation.arizona.edu - eastern gray squirrel

Koprowski, J. L. 1992. Removal of copulatory plugs by female tree squirrels. Journal of Mammalogy 73(3): 572-576.

thackerk1 — Tue, 23 Jul 2019 00:00:51 +0000

Authors

John L. Koprowski

Copulatory plugs form in the vagina of females from the semen of male fox squirrels (Sciurus niger) and eastern gray squirrels (S. carolinensis). Plugs are opaque white with waxy to rubbery consistency resembling those of other rodents. Although copulatory plugs frequently are hypothesized to prevent the successful copulation of subsequent males, female tree squirrels often remove the plug within 30 s of copulating and either discard or consume it. The removal by the female of a copulatory plug suggests that conflict may exist between the reproductive strategies of the sexes.

Additional Information

Removal of Copulatory Plugs by Female Tree Squirrels

Date of publication:

1992

Topics

reproduction

fox squirrels

eastern gray squirrel

copulatory plugs

Koprowski, J. L. 1993. The role of kinship in field interactions among juvenile gray squirrels (Sciurus carolinensis). Canadian Journal of Zoology 71: 224-226.

thackerk1 — Mon, 22 Jul 2019 23:58:01 +0000

Authors

John L. Koprowski

Adult eastern gray squirrels influence recruitment into local populations by directing aggression at juveniles and nonresidents. However, the role of juveniles in the social dynamics of squirrel populations is poorly understood. Field interactions among juvenile squirrels were studied between littermates and nonlittermates. Amicable interactions occurred only between littermates, while aggression was directed almost exclusively at nonlittermates. Juveniles within their own natal areas dominated nonresident juveniles. Interactions among juveniles appear to be influenced by kinship and may be important in determining recruitment patterns in squirrel populations.

Additional Information

The role of kinship in field interactions among juvenile gray squirrels (Sciurus carolinensis)

Date of publication:

1993

Topics

eastern gray squirrel

juvenile

littermates

nonlittermates

interactions

Koprowski, J. L. 1993. Alternative reproductive tactics in male eastern gray squirrels: "making the best of a bad job". Behavioral Ecology 4(2): 165-171.

thackerk1 — Mon, 22 Jul 2019 23:56:46 +0000

Authors

John L. Koprowski

Male eastern gray squirrels (Sciurus carolinensis) congregate around and pursue a female on her single day of estrus. The tactics of uniquely marked adult males were monitored during winter mating bouts from 1986 to 1990 to examine variation in male copulatory success. Two tactics were chosen by males: active pursuit or satellite. Active-pursuit males were dominant and defended proximity to females. Satellite males were subordinate and remained dispersed in the female's home range. Active pursuit was used only by males ≤2.75 years old. The switch point between the tactics is about 3 years. Copulations were not distributed evenly among males, with about 30&percnt; of all adult males failing to copulate during a breeding season. Active pursuit was the most successful strategy, with male success attributed to the ability to defend access to the female. However, satellite males successfully copulated due to the escape of females from dominant males. Females appear to avoid the overt aggression characteristic of the competition among active-pursuit males by running from the group of males. Male success after a female's breakaway was evenly distributed between the two tactics and accounted for all copulations by satellite males. The active pursuit and satellite tactics appear to be a conditional evolutionarily stable strategy where young, subordinate males are “making the best of a bad job”.

Additional Information

Alternative reproductive tactics in male eastern gray squirrels: “making the best of a bad job”

Date of publication:

1993

Topics

eastern gray squirrel

copulation

reproductive tactics

satellite males

Koprowski, J. L. 1994. Sciurus carolinensis. Mammalian Species 480: 1-9.

thackerk1 — Mon, 22 Jul 2019 23:50:42 +0000

Authors

John L. Koprowski

Information on the Sciurus carolinensis, or commonly known as the Eastern gray squirrel.

Additional Information

Sciurus carolinensis

Date of publication:

1994

Topics

eastern gray squirrel

distribution

fossil record

general characteristics

ecology

behavior

genetics

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.

Additional Information

Mammalian Species 48:66-72

Date of publication:

2016

Topics

Mearn’s squirrel

tree squirrel

endemic species

eastern gray squirrel

Sierra de San Pedro Mártir

Mexico

Research Categories

Natural History Threatened and Endangered Species