Bite force and jaw biomechanics in the subterranean rodent Talas tuco-tuco (Ctenomys talarum) (Caviomorpha: Octodontoidea)

BECERRA, FEDERICO; ECHEVERRÍA AI; VASSALLO, AI; CASINOS, ADRIÀ

CANADIAN JOURNAL OF ZOOLOGY

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Lugar: Otawa; Año: 2011 vol. 89 p. 334 - 342

0008-4301

Abstract: The Talas tuco-tuco (Ctenomys talarum Thomas, 1898) is a South American subterranean rodent that digs usingboth forelimbs and incisors, the latter being used when animals face hard soils and fibrous roots. In this rodent, the incisorsare also used during intermale competition for mates. Bite forces were measured on wild females (n = 21) and males (n =21) (both adult and young individuals) using a force transducer. Bite force was significantly higher in adult males than in females(32 vs. 27 N, respectively). Bite forces calculated on the physiological cross-section of jaw adductor muscles in dissectedspecimens were slightly higher than in vivo measurements. Regressions against body mass showed that bite forcescaled with positive allometry, with slopes of 0.89 (females) and 0.99 (males). No significant differences were observed, neitherin the slope nor in the y intercept of both sexes’ equations; therefore intersexual differences in bite forces observed inadults should mainly be due to size dimorphism. Considering that soil hardness of C. talarum’s typical habitat averages100 N/cm2, and taking into account incisor’s cross-section, it was assessed that the pressure exerted by jaw adductormuscles at the incisors level is three times higher than that required for soil penetration.