COMPARISON OF MORPHOLOGICAL CHARACTERISTICS IN GECKO TOE PADS

Abstract

The property of adhesive ability has proved advantageous to many terrestrial animals, such as lizards. Geckos, lizards in the family Gekkonidae, have been recognized for their clinging ability on various surfaces at horizontal and vertical positions. Gecko toe pads play an important role in their ability to ascend or walk on different surfaces. Previous studies show that with the help of structures called setae, interactions with flat surfaces become frictional, allowing forces like van der Waals to create molecular bonds with setae. However, the chemical mechanisms of geckos’ clinging ability do not account for uneven surfaces. Previous studies in Duncan Irschick’s lab focused on toe pads’ morphological characteristics that may explain the phenomenon of geckos’ adhesive ability on uneven surfaces. More specifically, gecko toepads’ area was compared to the body size to measure allometry of geckos. While it was discovered that toe pad shape and size contribute to the adhesive ability of gecko feet, it is unknown whether an “ideal” shape of the gecko toe pad may increase their aptitude for clinging to surfaces of diverse dimensions. Therefore, the purpose of this study was to determine if there is variation in toe pad dimension among gecko species. Photograph samples of the toe pads of various gecko species were studied by measuring the length and width of the toe pads. After computing the length to width ratio for these gecko species, our studies reveal a frequent pattern in length to width ratios of 1:1 ratio and 3:2. This suggests that equal ratio or slightly higher length proportions of toe pads may contribute to geckos’ ability to cling onto more irregular surfaces. This study will help to gain better insight on geckos’ climbing performance during different surface conditions and clarify the functional relevance of the adhesive nature of toe pads.