Ecology of the Eastern Massasauga (Sistrurus Catenatus Catenatus) From Carlyle Lake, Clinton County, Illinois
Detailed studies of the life history and ecology of an organism are important in assessing range-wide variation within species. Additionally because of global declines in biodiversity, knowledge of an organism's life history and ecology become central to developing conservation and management regimes. I studied populations of Eastern Massasaugas (Sistrurus catenatus catenatus) at its southern range limit from 1999--2003. I found no sexual size dimorphism (SSD) present in either snout-vent length (SVL) or mass but SSD was present for tail length (TL). I observed variation in growth rates of cohorts and models predicted the 1998 and 1999 cohorts simultaneously matured in 2000. Contrary to previous research, gravid females did not have warmer body temperatures (Tb) than non-gravid females and males. Body temperature gradually stabilized between a photoperiod of 10 hrs to 14 hrs and snakes achieved the warmest Tbs during midday with >12.5 hrs of light. Sex and reproductive states (gravid females, non-gravid females, and males; SRSs) frequently changed locations but did not differ in the distances moved. Gravid female movements peaked in spring and summer, non-gravid females in spring and fall, and males in summer and fall. There were no significant differences in activity area between SRSs or size classes. Snakes occupied activity area segments longer as photoperiod increased. Massasaugas preferred grassland habitats, but in the fall habitat use patterns were random. Early in the active season, gravid females preferred more open habitats compared with males and non-gravid females.
University of Illinois - Urbana-Champaign
Networked Digital Library of Theses and Dissertations
University of Illinois at Urbana-Champaign