Tail Length Evolution in Deer Mice: Linking Morphology, Behavior, and Function

Area of Science:

• Evolutionary biology
• Biomechanics
• Animal morphology

Background:

• Understanding how morphological variation influences animal performance and fitness is crucial for evolutionary adaptation.
• Long tails have repeatedly evolved in arboreal rodents, including deer mice (Peromyscus maniculatus) in forested habitats.

Purpose of the Study:

• To investigate the functional significance of tail-length variation in deer mice.
• To test hypotheses regarding tail morphology's role in arboreal locomotion and substrate navigation.

Main Methods:

• Computational modeling using museum records of natural tail-length variation.
• Laboratory studies assessing tail function in behavioral contexts.
• Analysis of caudal vertebrae shape and number in relation to tail curvature.

Main Results:

• Deer mouse tails primarily influence body roll during arboreal locomotion, with minimal impact on static center of mass or pitch/yaw correction.
• Tail effectiveness in locomotion shows a non-linear relationship with common tail-length metrics.
• Caudal vertebrae shape correlates with intervertebral bending angle, but observed differences in tail length and vertebra number between forest and prairie mice do not appear linked to a tail curvature trade-off.

Conclusions:

• Intraspecific variation in tail length can significantly affect organismal performance during locomotion.
• Functional trade-offs related to tail curvature do not fully explain observed differences in tail morphology between habitat-specialized deer mouse populations.
• Simple models are valuable for generating and testing hypotheses about trait variation and its functional consequences.