viani,nick_4google-2American Dipper (displaying the nictitating membrane, an additional translucent eyelid that allows the creature to see while affording its eyes additional protection. This is especially handy for birds that search for food underwater and for birds of prey flying at high speed, as it prevents their eyes from drying out.
American Dipper (displaying the nictitating membrane, an additional translucent eyelid that allows the creature to see while affording its eyes additional protection. This is especially handy for birds that search for food underwater and for birds of prey flying at high speed, as it prevents their eyes from drying out.