Meeting Abstract
Seismic communication is the generation and transmission of vibrations through natural substrates to convey information. Seismic communication is widespread in terrestrial animals; in kangaroo rats, it is characterized as a foot drum (high frequency drumming of the hind feet) or a foot roll (drumming with two feet simultaneously or alternating onto the substrate). These behaviors are described in the context of territoriality, predator deterrence, and to alert offspring, highlighting the importance of these signals to the survival and reproduction of kangaroo rats. Previous studies with oscillograms revealed that some species of kangaroo rats foot drum at ~90 Hz, which exceeds the capacity of typical skeletal muscle (25-30 Hz), but the mechanics of this behavior remains undescribed. Here we use 3D high-speed video recording of foot drumming desert kangaroo rats (Dipodomys deserti) in the wild to describe kinematics and test whether kangaroo rats might need a specialized anatomical feature to foot drum. We found that kangaroo rats foot drum at ~6 Hz and foot roll at ~16 Hz. At the start of a foot drum, the ankle flexes and reaches a height that is ~20% of the animals height. Then the ankle extends and hits the ground to produce the drum sound, then flexes slightly to reposition. The frequency of foot drumming by the kangaroo rats does not exceed muscle capacity, and these animals mainly generate the ‘drum’ from their ankle joint. Our preliminary data suggest that desert kangaroo rats do not require a specialized feature to foot drum. Future work will investigate how kinematic modulation allows this species to communicate a range of diverse signals.
