- Crustaceans shed exoskeletons as they grow.
- Behavioral modifications ensure that loss of water is minimal, that the animals are exposed to favorable rather than extreme environmental conditions, and that the fine line between evaporation cooling and excessive dehydration is maintained.
- In most crustaceans the excretion of nitrogenous wastes requires that copious supplies of water be available for washing away the soluble end-products.
- Modifications in behavior must have occurred quite early in the transition of crustaceans from sea to land. Then, as now, appropriate behavioral responses to light, temperature, humidity and tidal cycles were crucial if a terrestrial animal was to survive.