Are elephants the only four legged animal in world?

No, elephants are not the only four-legged animals in the world. There are many, many four-legged animals, including:

* Mammals: Dogs, cats, horses, cows, lions, tigers, bears, giraffes, zebras, deer, sheep, goats, pigs, etc.

* Reptiles: Lizards, snakes, turtles, crocodiles, alligators, etc.

* Amphibians: Frogs, toads, salamanders, newts, etc.

* Birds: While birds don't walk on four legs, many have two legs they use for walking.

* Insects: Many insects have six legs, but some, like the woodlouse, have seven pairs of legs.

The world is full of amazing and diverse creatures!