Weights of Suburban Raccoons in Southwestern Ohio

Racoons (Procyon lotor) were collected during a 2 year study in the suburban village of Glendale, Ohio. Weight records (250) were kept on 150 individuals. Nonjuvenile males averaged 4.7 kg and females 4.1 kg. Ten juveniles averaged 3.4 kg in November. Mean summer-fall weight increase was 121% for 12 juveniles and 36% for 19-non-juveniles. Mean winter weight loss for 15 racoons was 16%. Malefemale differences noted in the pattern of seasonal weight fluctuation were attributed to the events of the annual reproductive cycle. Records for 18 males and 5 females showed that heavier individuals reached sexual maturity at an earlier age. A comparison of data from this study with similar data from other areas of the eastern U.S. suggests a positive correlation of average weight with latitude and a negative correlation with population density. OHIO J. SCI. 79 (3): 139, 1979 In preparation for an extensive winter lethargy period, raccoons in the northeastern U.S. are known to accumulate a large surplus of subcutaneous fat during summer and autumn months. When regular feeding is resumed in spring, little remains of this fat layer and raccoons are at their yearly weight minimum. This seasonal pattern of weight fluctuation has been documented by Stuewer (1943) in southwestern Michigan and by Mech et al (1968) in eastcentral Minnesota. Except for the work of Johnson (1970) in Alabama, there is little detailed information on the weights of raccoon populations farther south. The present study concerns weight data gathered during a 2 year (1973-75) field study of a highdensity raccoon population in the suburban village of Glendale in southwestern Ohio. METHODS AND MATERIALS Raccoons were captured with the #3 Havahart Live Trap and brought to the laboratory for examination and weighing. They were released the following day at the original site of capture. Ear-tags and toe-clipping methods were used to mark individuals. Traps were placed at semipermanent locations coinciding with probable Manuscript received 29 March 1978 and in revised form 29 August 1978 (#78-17). Present address: Department of Zoology, Ohio State University, Columbus, OH 43210. raccoon den sites, travel routes, and feeding areas. During the period 18 March through 30 November 1974, traps were set an average of 19.4 nights/month accumulating 4,857 trap nights. Population density (raccoons/ha) was calculated by averaging estimates derived from 3 different methods as described by Hoffmann and Gottschang (1977). With 15 April as the median birth date (Sagar 1956), raccoons were classified into juvenile ( 2 years) age categories. In general, males less than 3.9 kg or females less than 3.4 kg were classified as juveniles, males from 3.9-4.8 kg or females from 3.4-4.1 kg as yearlings, and males above 4.8 kg or females above 4.1 kg as adults. When body weight itself was not sufficient to classify these groups (a problem that was especially evident in the fall and winter) the following criteria were used: tooth measurements and wear (Grau et al 1970), extrusibility of the os penis (Sanderson 1961), externally measured length of the baculum (Sanderson 1950), size of testis (Sanderson and Nalbandov 1973) in males, and teat appearance in females (Sanderson and Nalbandov 1973). Non-juvenile defines animals of either yearling or adult status. Only one measurement per individual was used in calculations of mean monthly or seasonal weights. Student's /-test was used to determine the significance of difference between means. Summer-fall weight gain was calculated using the lighest spring-early summer weight and the heaviest late summer-fall weight for an individual. Winter weight loss was calculated using the heaviest fall and lightest late winter-spring weight. The 234 ha study area in Glendale, Ohio has been described by Hoffmann and Gottschang (1977). The average yearly length of