Sticking ability in Spix's disk-winged bat, Thyroptera tricolor (Microchiroptera: Thyropteridae)
Roosting Spix's disk-winged bats, Thyroptera tricolor, use disks on their wrists and ankles to cling to smooth leaves. In 584 trials we tested the ability of 31 T. tricolor and 121 other bats lacking disks (461 trials with 18 species from three families) to adhere to (i) medium-grade sandpaper, (ii) Lexan polycarbonate, (iii) solid sheet aluminum, and (iv) porous sheet aluminum. While T. tricolor readily adhered to smooth surfaces, the other species did not. Thyroptera tricolor did not show the same ability to adhere to rough surfaces as the other species that were tested. As was demonstrated by their performance on porous aluminum and sandpaper, the disks of T. tricolor worked by suction and sometimes by wet adhesion. In the course of adapting to adhere to smooth surfaces, T. tricolor appear to have lost some ability to roost on rough ones, although one adult T. tricolor climbed on a screen covering the inside walls of the polycarbonate cage by interlocking its thumb claws with the surface.