Undersea Creatures

Earth is a water planet--almost two-thirds of it is covered by ocean--and while sliver of life exists on land, the majority of the  planet's population thrives in the seas. Splashing in the shallows, clinging to reefs, and lurking in the depths are multitudes of fantastic creatures, each one specially equipped for life underwater. Internal lights help dwellers of the deep seas pierce through the darkness. Regenerating teeth keep hunters armed and sharp. Color-changing abilities and swiveling eyes help vulnerable animals spot danger before it spots them. What other fascinating tools and tricks does it take to survive in this extremely crowded, high-pressure, and watery world?