We characterized differences in escape behavior among syntopic parthenogenetic and gonochoristic whiptail lizards (Teiidae: Aspidoscelis) in western Texas by performing 2 experiments. The first experiment revealed that Aspidoscelis exsanguis (parthenogenetic) allowed a human simulated predator to approach significantly closer than Aspidoscelis neomexicana (parthenogenetic), and both species allowed a significantly closer approach than Aspidoscelis tigris (gonochoristic). Furthermore, A. neomexicana and A. exsanguis did not flee as far as A. tigris, but this difference in flight distance was not statistically significant. Temperature was not correlated with approach distance or flight distance for any of the above species. The second experiment determined that, when captured, Aspidoscelis tesselata (parthenogenetic) was more likely to release cloacal contents on a human captor than A. tigris (gonochoristic).