Mud Day 2011, Westland, Michigan, United States

Mud is similar to muck, but lacking significant quantities of humus, and often containing higher proportions of sand.
As habitat
Mud can provide a home for numerous types of animals, including varieties of worms, frogs, snails, clams, and crayfish. Other animals, such as pigs and elephants, bathe in mud in order to cool off and protect themselves from the sun. Humans have also used mud as a building material, or a sealant material.