Brontosaurus, more accurately called Apatosaurus, was a sauropod. Like all huge sauropods, they walked on four legs.
The animal that walks on all fours, then on two legs, and then back on all fours again is a human. As babies, humans crawl on all fours, then learn to walk upright on two legs, and might sometimes crawl again for various reasons.
Raccoons, like dogs, can walk short distances on two legs but almost always walk on all fours.
There bodies just aren't built for walking like that. It is like humans walking on all fours. We can get on all fours but it is harder to walk and hurts over time. Meerkats legs are not very big and they are not strong enough to continuously walk on two legs.
The Tasmanian devil walks on all fours, not two legs like some marsupials do (such as the kangaroo).
Well for one thing they walk on two legs, but have also been seen walking on all fours.
A male gorilla is up to 6 ft tall from feet to head when standing on two legs. When it is on all fours, it is only 5'6 ft tall.
A lion standing on its hind legs can reach a height of about 6 feet (1.8 meters). However, lions typically walk on all fours and do not frequently stand upright.
Not all animals walk on all fours. Humans are animals too! Those animals that do walk an all fours do so because it is an efficient and stable means of movement. The earliest land creatures were fish or frog like and "crawled" along the ground. Later on animals evolved that larger and more powerful legs. Animals like cheetahs can run very fast on four legs. The ancestors of human beings walked mainly on all fours - like modern gorillas and chimpanzees do. We're not sure exactly why human beings evolved to walk on two legs, but it has caused back problems for human beings because we have inherited a spine that was originally designed for four-legged creatures.
Brontosaurus is an invalid name for Apatosaurus excelsus. Apatosaurus was a sauropod, and like all sauropods, it walked on four legs. However, very young Apatosaurus could run on two legs like a basilisk lizard to escape danger.
The Sphinx famously asks travelers the riddle: "What walks on four legs in the morning, two legs at noon, and three legs in the evening?" The answer is "a human," as they crawl on all fours as a baby, walk on two legs in adulthood, and use a cane in old age. Those who cannot answer the riddle are said to be devoured by the Sphinx.
The riddle given by the Sphinx is: "What walks on four legs in the morning, two legs at noon, and three legs in the evening?" The answer is "a human." In the morning of life (infancy), a person crawls on all fours; during adulthood (noon), they walk on two legs; and in old age (evening), they often use a cane, thus walking on three legs.
No we do not have two legs we have none we walk with are arms.