Lydia Crane | 2025 I.S. Symposium

Name: Lydia Crane
Title: Behavioral Differences and Survival Estimations in Melanistic and Gray Morph Squirrels
Major: Biology
Minor: Spanish
Advisors: Richard Lehtinen

Color polymorphisms are important in studying and understanding behavior and evolutionary processes. Melanism in eastern gray squirrels (Sciurus carolinensis) provides a good example of this, with two common color morphs, the gray morph and melanistic morph. In this study, I measured behavioral differences between these two color morphs by performing walking surveys where I recorded the behaviors of squirrels along specific routes. I also began a mark and recapture study where I trapped and ear tagged squirrels in order to track survival. I found that there were significant differences in behavior between the color morphs, specifically frequency of bird feeder use, tail-up posture, chases, copulations, and wrestle-play behavior. There was also a difference in the frequency of bald patches observed on gray morph and melanistic squirrels. Additionally, the two color morphs had different activity patterns, specifically at different times of day, times of year, and temperatures. There are several hypotheses for why gray morph and melanistic squirrels behave differently, one of them being that melanistic squirrels have a thermal benefit during cold weather. However, my results aren’t entirely consistent with this hypothesis. Another interesting implication of these behavioral differences is that they could be a precursor to speciation down the road. Overall, this study indicates differences in behavior among the different color morphs, but the processes driving these differences are still unknown and should be studied in the future.

Posted in Symposium 2025 on May 1, 2025.