nsfw:racy: Very Likely | adult: Possible ocr: a The Machinery ofMovement Quit Skeleton Exoskeletons protect their owners - they function as armor - but seem to be inevitably rather heavy. Compare a very large spide er (such as a tarantula) with a very small mammal or bird (a shrew or a humming bird). They may have about the same body mass, but the bird or mammal's skeleton is only about 4%0 ofl body mass and the S pider'sa about 9%. A water snail, again of the same body mass, would ha ve a shell of about 25%0 of l body mass, six times as heavy as the mammal skeleton. (These comparisons are made between similar-sized animals because large ...
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