BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38, PT. 11(6)


moderada a extensa sobreposici6n de Ambitos de hogar. Las hembras tendieron a ser mis exclusivistas en el uso
de espacio y a presentar una mayor estabilidad en los ambitos de hogar comparado con los machos. Los machos
frecuentemente cambiaron de ambito de hogar al tarmino de la temporada de months. Se presentaron tres
diferentes medidas de tamaino de ambito de hogar. Los valores promedio para machos y hembras fueron 141.6 ha
y 64.4 ha, respectivamente (poligono convexo minimo corregido). El tamailo de los ambitos de hogar
individuals de los machos estuvo influenciado por el habitat, siendo mis grandes en habitats supuestamente mis
pobres, siendo ademas influenciados por el tamaino corporal. Las distancias promedio recorridas por hora fueron
234 m en machos y 178 m en hembras. Los movimientos nocturnos de machos y hembras promediaron 1835 m
y 1465 m, respectivamente (miximos: 4665 m y 3973 m). Las distancias recorridas fueron asociadas con la
temperature, tamafio de ambito de hogar o tamailo corporal. Datos muy limitados de otras regions sugieren que
esta poblaci6n de comadrejas utiliza un mayor espacio.


 INTRODUCTION


 The spatial distribution of an animal population is ultimately shaped by
environmental factors, such as the quality and distribution of resources in space and
time, intraspecific competition, and predation pressure (Clutton-Brock and Harvey
1978; Davies and Houston 1984; Wrangham and Rubenstein 1986). The spatial
distribution, on the other hand, influences the social organization including the mating
system, which in turn affects morphological, behavioral and other traits such as sexual
size dimorphism (Clutton-Brock and Harvey 1978; Rubenstein and Wrangham, 1986;
Ryser 1992).
 The spatial organization of the Virginia opossum has been subject to uncertainty.
In his review, Gardner (1982) termed opossums solitary wanderers that rarely remain
in any area and do not maintain separate home ranges. More recent studies (Gillette
1980; Allen et al. 1985; Seidensticker et al. 1987), however, suggested that opossums
live in well defined and at least seasonally stable home ranges.
 Here I present results on space use and home range size of opossums in north-
central Florida. The opossum is a nocturnal, solitary, omnivorous marsupial about the
size of a house cat, ranging over most of the eastern United States and south to Costa
Rica, and showing a wide range of ecological tolerance (Gardner 1982). In Florida,
opossums have two breeding seasons of about four weeks each in January/February
and May, respectively (Ryser 1992; Sunquist and Eisenberg 1993). The young are born
after a 13-day gestation, weaned at the age of about 100 days (Reynolds 1952; Wright
1989), and are sexually mature by the end of the year. The data were collected during
a two-year radio-tracking study as an essential basis for understanding the opossum
mating system and male mating strategies (Ryser 1990, 1992). Additionally, I
collected quantitative data on activity and movements to investigate geographical and
sex differences in these parameters as well as individual and environmental factors
influencing activity and movement. Despite the opossum's abundance in many parts of
its range, reliable, quantitative data on activity, movement, and home range size are
rare. Gillette (1980) and Allen et al. (1985) presented data on home range size and
Allen et al. (1985) and Seidensticker et al. (1987) on nightly movements. Activity has
been studied in captivity by McManus (1971) and in the field by Seidensticker et al.