These crustaceans have an extremely stiff exoskeleton that provides protection and helps them resist desiccation (drying out).
While most cephalopods are known for their soft, flexible bodies, the cuttlefish has a rigid internal structure called the cuttlebone.
Known for their hard, exoskeletal shell, horseshoe crabs have a rigid, almost immovable structure that is highly protective.
The hard, bony shell protects their vital organs and is incredibly stiff, offering both defense and structural support.
Arthropods possess exoskeletons made of chitin, which gives them stiffness and helps protect them from predators and environmental hazards.
These animals have stiff, calcified shells that serve as their primary defense mechanism.
Although not exactly "stiff" in a traditional sense, giraffes have a very rigid neck structure