Exoskeleton and Endoskeleton Size Limits
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
An exoskeleton must thicken sharply as body weight increases, since doubling size roughly increases weight eightfold, capping most exoskeleton-bearing animals at a small size; an endoskeleton scales more efficiently since muscles attach outside it.
Show
Insects and crustaceans stay small under their exoskeletons, while endoskeleton-bearing whales grow to enormous size.
Watch for
Molting lets an exoskeletal animal grow only in stages, not continuously.