How does a crab moves, and why​

Most crabs usually stroll on the beach by walking sideways. But crabs can also walk forward, backward and diagonally. Because crabs have stiff, jointed legs, they move faster and easier walking sideways. ... A crab walking sideways pulls itself along with one set of legs and pushes with the other.

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.