Why don't mammals have more than 4 limbs?

Mammals usually have 4 limbs because it’s the most efficient way for them to move around and live their lives.

Imagine you’re playing with your toy car, it has 4 wheels, right? Those wheels help it go straight, turn corners, and even speed up. Now think of your body like that toy car. If you had more than 4 limbs, like 6 or 8, it would be harder to move smoothly and keep balance. It’s like trying to drive a car with 6 wheels, it might wobble and feel strange.

When animals grow from babies to adults, their bodies change in special ways. If they had too many limbs, their bones and muscles would have to work together in very complicated ways. That’s like trying to dance with 6 legs instead of 2, it's harder to do the same steps.

Also, most mammals need to move quickly to find food or escape from danger. Having just 4 limbs gives them a perfect mix of speed and balance, like having the right number of wheels on your toy car to go fast and stay steady!