A
quadruped is an animal that normally walks or runs on four legs.
The word comes from the Latin words
quad (four) and
ped (foot).
A quadruped is a land mammal that walks on four feet.
The term "quadruped" has its root in Latin language - "quad" meaning "four," and "ped" meaning "feet" - so the term literally means "four feet."
Most animals that walk are considered quadrupeds, although it's important to note that not all four-limbed vertebrates - also known as tetrapods - fall into the quadruped category.
Humans, for instance, have four limbs, but only two of those limbs are used for walking, therefore humans fall into the category of a biped - an animal that uses two legs to travel. Notably, birds are also considered bipedal.