Research Themes

Paleomiddens

Heat, Death & Sex

Not only have woodrats left a rich fossil history of the late Quaternary, but because they are extant we can study them in the field and/or laboratory.  We use a combination of approaches to examine many of the same broad questions addressed by our paleomidden studies.  By examining museum and field data for various Neotoma populations, for example,  we have been able to firmly establish relationships between ambient high/low temperature and body size.  We have found some intriguing and unexpected patterns that are now leading to investigation of the importance of body size/life history tradeoffs.  Woodrats in Death Valley, for example, are twice as large as expected on the basis of ambient high temperature (Smith and Charnov 2003).  We now believe that these animals may have “solved” the problem of life in such an extreme environment (mean maximum July temperature > 46C!) by becoming annuals (i.e.,  evolving a semelparous reproductive strategy).  We are currently investigating this prediction and have begun a long-term study of animals at Furnace Creek, Death Valley (-84m elevation).  We are conducting monthly trapping and characterizing fitness by measuring in vivo reproductive effort and survivorship for adults and juveniles.