fourlegged

Fourlegged is a non-technical adjective used to describe animals that move predominantly on four limbs. The technical term is quadruped, while four-legged is the common-language form used in everyday speech. The phrase can also describe objects with four feet, such as furniture or stands, though in biology the term is usually applied to living organisms.

In animals, limbs are typically arranged beneath the body to support weight and enable efficient propulsion. Foot posture varies among quadrupeds: plantigrade (the whole foot contacts the ground, as in humans and bears); digitigrade (only the toes touch the ground, as in dogs and cats); and unguligrade (on hooves, as in horses and deer). Gait progression ranges from walking to trotting, cantering, and galloping, with limb coordination adapting to speed and terrain. The speed and efficiency of movement are influenced by body size, limb length, and musculoskeletal structure.

Evolutionarily, quadrupedal locomotion arose with early tetrapods when vertebrates colonized land. Today, four-legged locomotion is widespread across many groups, including mammals (dogs, horses, cattle, elephants), reptiles (turtles, crocodilians, certain lizards), and some amphibians. While many species are strictly quadrupedal, others can vary their locomotion, using fore- or hindlimbs for other functions or occasionally standing on two legs.

See also quadruped.