Trade-offs between sprinting and clinging ability in Kenyan chameleons

Measured the force required to pull chameleons from perches and the sprint speed of chameleons on flat surfaces and on perches of varying diameters. Chamaeleo jacksonii is almost completely arboreal, whereas C. dilepis is semi-arboreal and is often observed on the ground. The authors tested the following hypotheses: 1) each species has relatively greater sprinting and clinging abilities on surfaces corresponding to those it uses most frequently; or 2) a trade-off exists between maximizing clinging and sprinting abilities. Results support the second hypothesis: C. dilepis runs faster than C. jacksonii on almost all diameters, but has poorer clinging ability on all diameters. The extreme adaptations of chameleons may have allowed them to enter and diversify in a novel adaptive zone, but also may constrain the direction of subsequent adaptive change. -from Authors