Abstract
The study was conducted in a transitional zone between the Gulf Prairies and Marshes, and the South Texas Plains. In its present state, the area is a brush-grass complex. The rabbits are members of the Sylvilagus floridanus group, with characteristics of coat color and habitat most closely related to that of S. f. chapmani. Adult members of the population are smaller in stature than the cottontail rabbits of the more northern states. Data on growth and age determination are given for body weight, crow-rump length, hind foot length, eye-lens weight, four lower jaw measurements, and for the closure of the epiphyseal cartilage of the humerus. The lens weight is the best criterion of age. Skeletal growth is virtually completed by the fifth month of age. Reproduction in the population occurred in any month of the year, with peaks in late winter to early spring, and in the early fall. Evidence of a correlation between rainfall and reproduction, and between temperature and reproduction, existed. Ovulation rates, conception rates, litter sizes, and the size of the teste varied from month to month, from year to year, and from age class to age class. Evidence of polyovularity and of skips in post-partum pregnancy were found. Some juvenile females were also multiparous in many instances. The adult rabbits contributed more than 50 per cent of the annual crop of young. The sex ratio in the population varied from year to year, with different population densities, and with the method used to collect the data. Survival rates and population density also varied from year to year. Inclement weather and predator pressure probably had a direct bearing on these variations. Population density differed between different plant communities. Within the same plant community, the density of the population was influenced by the distance of the rabbits form the nearest road. The home range of male rabbits exceeded that of the females. The spleen gland seemed a good indicator of stress in the population. A physiological preparation for, and a high metabolic rate during, the winter was indicated by food consumption. Coprophagy was inversely related to the activity of the rabbits. Two periods of molt occurred; one in October, the other in April. A correlation existed between the molt and daylenth. Nor relationship between molt and reproduction was found.
Bothma, Jacobus du Plessis (1969). Population ecology of the cottontail rabbit, Sylvilagus floridanus, on the Welder Wildlife Refuge, South Texas. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -127503.