How kangaroo rats utilize their tail while re-orienting

January 3 – Febuary 28, 2021

Meeting Abstract

S5-6  Tue Jan 5 14:30 – 03:00  How kangaroo rats utilize their tail while re-orienting Schwaner, MJ*; Freymiller, GA; Clark, RW; McGowan, CP; University of Idaho, Moscow, ID; University of California San Diego, San Diego, CA; University of California San Diego, San Diego, CA; University of Idaho, Moscow, ID

To avoid predation by snakes, kangaroo rats (D. deserti) use ballistic vertical leaps – up to over ten times their hip height. While airborne, these animals change their orientation. Simultaneously, they move their tail through the air, bending and twisting it around and over the body. These observations suggest that kangaroo rats utilize their tail for not only balancing their body while airborne, but also to facilitate body re-orientation. To test this hypothesis, we collected three-dimensional video data on kangaroo rats exhibiting a predator escape response to a self-built, artificial predator attack simulator. From these video data we quantified angular momentum of the tail and the body in the yaw-plane (rotation around the vertical axis). Preliminary data suggest that tails do play an important role in balancing and orienting kangaroo rats while airborne, as body angles of escaping rats show a step-wise re-orientation. While all tail segments are closest to the body’s rotation axis (up or down in the air, low tail moment of inertia in z-plane), the body orientation change is minimal. This is typically followed by an increase in tail moment of inertia as the tail is sweeping away from the body, during which the body orientation changes again. Body rotation typically goes through 2 to 4 orientation steps while airborne. Time airborne, jump height, and jump distance do not correlate with number of orientation steps. This suggests that this step-wise re-orientation is created by tail movement, as legs are tucked under the body during this aerial period. Further investigation of 3D tail parameters will elucidate how the kangaroo rat utilizes its tail to facilitate aerial re-orientation of the body.

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