Here are the two ways that forelimbs are different than hind limbs: 1. hind limbs tend to be sturdier, stronger, longer - these limbs are used to propel the frog while jumping, which is why they have to be stronger than the forelimbs; 2. hind limbs are more firmly attached to the spine - because they are stronger and require more strength for the frog's activities, they also have to be connected to the spine more than the forelimbs