Meeting Abstract
To quantify oscillatory digging forces, Forces measured by the tunnel-tube were analyzed using Fourier analysis as a function of frequency. The tunnel-tube was used here to quantify scratch-digging forces in three closely-related rodents: pocket gophers, kangaroo rats, and pocket mice. Animals from each species dug in soil from their trapping site packed into the tunnel-tube. Digging frequency was lowest in pocket gophers at 15 Hz and highest in kangaroo rats at 22 Hz. This was unexpected as pocket mice have a lower body mass, but dug at a frequency of 19 Hz, a slower speed than kangaroo rats 1.5x their size. Scaling of digging frequency to body mass results in a scaling exponent of -0.15, hinting at elastic similarity. Results of the Fourier analysis of force showed that vertical force scaled with body mass, and fore-aft force (into the digging substrate) scaled with positive allometry. It remains unclear whether this trend reflects true positive allometry or digging specialization in pocket gophers vs the two smaller species.
