Animating Reptiles and Snakes
Reptiles and snakes are creatures that have unique forms of locomotion. Unlike mammals, which primarily use their legs, snakes and reptiles tend to use their bodies and spines as a major part of locomotion.
Quadrupedal reptiles, such as lizards and crocodiles, tend to keep their stomachs very close to the ground, with the legs splayed out to the side, as shown in Figure 1. With few exceptions, most four-legged reptiles have the same awkward position. This keeps the reptile's center of gravity quite low and makes it more difficult to raise the body off the ground. As a contrast, quadrupedal mammals have their limbs directly underneath the body, which allows the legs to carry all the animal's weight, which is more efficient.
Figure 1 Crocodiles, as well as lizards and other reptiles, have legs that are splayed out to the side.