system
Given the following post, respond as if you're commenting on Reddit:
human
Why do some animals hop instead of walking?

Some birds, rodents, marsupials etc hop rather than stride, but not all. What is it that makes it a better way to move for only certain members of the species. Why is it always one or the other and not some mix? Are there any examples of it being individual case by case rather than across the board for that animal?
gpt
Hopping is usually taken up because it’s a low energy way to move while keeping some sort of high speed mechanism for escapes intact. Rabbits can sprint incredibly fast, but their morphology for this makes it so hopping is the easier method of movement when they aren’t running for their lives. Similarly for frogs, their legs are adapted for swimming and strong leaps to catch prey and avoid predators. So the easiest form of relaxed locomotion is a hop.