View allAll Photos Tagged 3rd
Now this I thought was pretty cool. I took a ton of shots of this pelican hoping to catch his 3rd eyelid as I heard they had one.
Here is a brief description of it from Wikipedia:
The nictitating membrane (from Latin nictare, to blink) is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten the eye while also maintaining visibility. Various reptiles, birds, and sharks have a full nictitating membrane, whereas in many mammals, there is a small vestigial remnant of the membrane present in the corner of the eye. Some mammals, such as camels, polar bears, seals, and aardvarks, also have a full nictitating membrane. It is often called a third eyelid or haw and may be referred to as the plica semilunaris or palpebra tertia in scientific terminology.
Nictitating membranes are found in birds, reptiles, amphibians, and fish, but are less common in mammals, mainly being present in monotremes and marsupials.[1] In humans, the plica semilunaris (also known as the semilunar fold) and its associated muscles are thought to be probably homologous to the nictitating membrane seen in some other mammals and other vertebrates.[2] Only one species of primate—the Calabar Angwantibo—is known to have a functioning nictitating membrane.[3]
U.S. Coast Guard Petty Officer 3rd Class Jack Harkness, an Boatswain's Mate assigned to Small Boat Station Cleveland, assists a student, on U.S. Coast Guard Cutter Neah Bay, October 5, 2022. Harkness assisted many students with the Davis Aerospace & Maritime Argonaut Program as they put on immersion suits for the first time. (U.S. Coast Guard photo by Petty Officer 3rd Class Crystal Burgess)
3rd place winner of the photography contest weekly theme: Graffiti.
Photographer: Renny Koerner-Brown