Because they no longer have their source of fuel: warm moist air above the sea.
Answer:
Examples of vestigial structures include the human appendix, the pelvic bone of a snake, and the wings of flightless birds. Vestigial structures can become detrimental, but in most cases these structures are harmless; however, these structures, like any other structure, require extra energy and are at risk for disease.
Explanation:
sincerely, micah
It allows it to hide under but still be able to see above it to catch flies
