Science Figures Interpreted and Analyzed by RealClearScience
When being chased and nipped at by a scary predator, lizards will often lose their tails in a process called autotomy. Like a chicken with its head cut off, the tail will then flop around by itself for about 30 minutes, distracting the disappointed predator. Assuming the predator doesn't eat the tail as a consolation prize, some lizards will return to eat it themselves, as the tail contains large fat deposits.
Similar to the precut "dotted lines" on coupons, the lizard's tail has built-in structural features at specific locations that allow for quick tail detachment. But the mechanism of how the tail is released is unknown. So, researchers in Denmark decided to investigate.
They analyzed detached tails from the gecko species Gekko gecko. (See photograph above.) The scientists noted that the gross and microscopic anatomy appear to be organized in such a way as to maximize surface area. The authors propose that friction and adhesion, similar to the mechanism by which the tiny "hairs" on gecko toes help them climb, are the primary forces holding the "precut" tail segments together. When a predator chomps down on the lizard's tail, the authors believe the lizard contracts muscles to disrupt the adhesive forces, dropping the tail.
Source: Sanggaard KW, Danielsen CC, Wogensen L, Vinding MS, Rydtoft LM, et al. (2012) Unique Structural Features Facilitate Lizard Tail Autotomy. PLoS ONE 7(12): e51803. doi:10.1371/journal.pone.0051803