Higher altitudes, where temperatures begin to decrease, have a direct effect on the size of "T. carnifex". Ficetola et al. (2010) discovered that living in colder temperatures resulted a body size increase in both male and female. Females in higher altitudes were found to be larger because they were carrying more oocytes and larger ovaries, which gave them a reproductive advantage over the smaller females. "T. carnifex" is poikilothermic and larger body sizes help to reduce heat fluctuations. Ficetola also found that fluctuations in body temperature of T. carnifex decreased when body size increased. An increase in body size also occurs where there is increased precipitation or nearby primary producers, due to the effect of increased resources on animals.