By Stacey Venzel
Of the five senses, sight is the strongest in turtles. Most turtles navigate and forage using visual cues.
Based on their habitat and survival traits, the type and strength of vision differs among species. Turtles can differentiate colors, travel in the dark and see underwater because they evolved to suit their needs.
Though the range and preference of colors differs among species, the majority of turtles see orange best, including shades of the color such as red and yellow. Gopher tortoises can see strawberries and flowers from yards away, making them good foragers. Sea turtles have adapted to green colors that penetrate the depths of the ocean.
Color changes during mating season in species like the painted terrapin also suggest that turtles can see a rainbow of colors, relying on the spectrum to distinguish between males and females.
Turtles have light receptors, too, that use brightness to determine night from day. The most noteworthy example of night vision is in sea turtle hatchlings who make their way to the sea at night following the light of the moon and stars.
Species that live on land and water have vision adapted for both habitats. However, sea turtles spend nearly their entire lives underwater, so they see clearly in the ocean but have fuzzy vision on land. If you have ever opened your eyes underwater and seen how blurry it looks, that this is approximately how the beach appears for a nesting sea turtle or hatchling.
Karen Eckert, David Gulko, Sea Turtles: An Ecological Guide (Honolulu, Mutual Publishing, 2004), 24, 74.
Carl J Franklin, Turtles: An Extraordinary Natural History 245 Million Years in the Making (St. Paul, Voyageur Press, 2007), 22.
Whit Gibbons, Judy Greene, Turtle: The Animal Answer Guide (Baltimore, The John Hopkins University Press, 2009), 18-19, 29.