An adaptation for defense in animals is spines in porcupine fish.
Porcupine fish have spines on their bodies that can be raised when they feel threatened. The spines act as a defense mechanism to deter predators from attacking the fish. When the spines are raised, they make the fish look larger and more intimidating, and the spines can also cause injury to the predator if it tries to bite the fish.
Croaking of a male toad is a type of communication that is used to attract mates or defend territory, but it is not an adaptation for defense.
Basking in lizards is a behavior that helps the lizards regulate their body temperature, but it is not an adaptation for defense.
Huddling together of penguins is a behavior that helps the penguins stay warm in cold environments, but it is not an adaptation for defense.