What is different about the way echidna and platypus react when being threatned by a predator?

When threatened by a predator, echidnas typically curl into a tight ball, using their spines for protection, while platypuses often dive underwater to evade danger. Echidnas rely on their physical defenses and camouflage, whereas platypuses use their agility and swimming ability to escape. This difference highlights their unique adaptations to their respective environments.