Ontogeny of running performance in the wild guinea pig (Cavia aperea)

Young of precocial species depend on their locomotory abilities to follow their mother to foraging areas, and to avoid predators. We measured for the wild guinea pig (Covia aperea), a relatively small species (adult mass 400-600 g) with particularly precocial young, how running ability develops with age and how it compares to adult performance. We also asked to what extent females are impaired in their Locomotor performance when pregnant, and tested how high adults can jump. Animals used trot and gallop for most Locomotion except when calmly foraging. They jumped to a maxima[ height of 60 cm from a standing start. Maxima[ escape speeds of adults averaged 4.12 m/sec, peak velocity measured was 6.0 m/sec. Newborn young, weighing only 77 g, were able to run at speeds up to 2.55 m/sec, and reached adult levels (about 4.0 m/sec) when only 20 days old. This is partly explained by a positive allometry of leg Length in comparison to mass. Locomotion of wild guinea pigs develops in a highly precocial manner and appears adapted to allow short bouts of high burst speed. Running speeds of adults are similar to those of similarly sized sciurids.