Total recoil: perch compliance alters jumping performance and kinematics in green anole lizards (Anolis carolinensis)

Abstract

SUMMARY Jumping is a common form of locomotion for many arboreal animals. Many species of the arboreal lizard genus Anolis occupy habitats in which they must jump to and from unsteady perches, e.g. narrow branches, vines, grass and leaves. Anoles therefore often use compliant perches that could alter jump performance. In this study we conducted a small survey of the compliance of perches used by the arboreal green anole Anolis carolinensis in the wild (N=54 perches) and then, using perches within the range of compliances used by this species, investigated how perch compliance (flexibility) affects the key jumping variables jump distance, takeoff duration, takeoff angle, takeoff speed and landing angle in A. carolinensis in the laboratory (N=11). We observed that lizards lost contact with compliant horizontal perches prior to perch recoil, and increased perch compliance resulted in decreased jump distance and takeoff speed, likely because of the loss of kinetic energy to the flexion of the perch. However, the most striking effect of perch compliance was an unexpected one; perch recoil following takeoff resulted in the lizards being struck on the tail by the perch, even on the narrowest perches. This interaction between the perch and the tail significantly altered body positioning during flight and landing. These results suggest that although the use of compliant perches in the wild is common for this species, jumping from these perches is potentially costly and may affect survival and behavior, particularly in the largest individuals.

Factors Affecting the Compliance and Sway Properties of Tree Branches Used by the Sumatran Orangutan (Pongo abelii)

“…Compliance ( C ) was calculated using equation 1 [10], where dy is the change in displacement and dF is the given force. …”

“…In contrast, it has generally been found that branches have too much compliance to return energy to locomoting animals. The high compliance leads to low oscillatory frequencies, so when animals jump off branches they lose contact before the branch has time to recover [5], [9], [10]. The result is a reduced jumping performance and energy loss.…”

“…The result is a reduced jumping performance and energy loss. Therefore, in general, it is assumed that higher compliance induces a locomotive cost to animals in the form of reduced performance and a higher energetic output [6], [10], [11]. In response, smaller primates face the problems of substrate variability and gap crossing in the canopy by adopting specialisations such as compliant gaits [12] and alternative leaping strategies [5], [13].…”

Foils of flexion: the effects of perch compliance on lizard locomotion and perch choice in the wild

“…We also found that, as in our laboratory study, green anoles jumped from compliant perches prior to recoil and did not use the energy stored in the perch for their jump (Gilman et al . ). Lastly, we found a significant negative relationship between perch diameter and compliance in most natural structures in the habitat; however, variability in compliance for a given diameter generally precludes the use of diameter as a proxy for compliance in this system.…”

“…Recently, we performed laboratory trials on the effects of perch compliance on jumping kinematics and performance in A. carolinensis , and we found that increased compliance resulted in significantly shorter jump distances and lower take‐off velocities (Gilman et al . ). Because these lizards occupy habitats in which they must jump to and from compliant perches, our results suggest that perch compliance may be an important structural variable that influences how this species negotiates its habitat.…”