A nigh heron with a fish that looks too big to swallow! Fish are always swallowed head first, and its a skill learnt by chicks at an early age. I've seen darters and pied kingfishers tossing fish deftly, before swallowing them head-first. (Photo by Mr Ramanan)
Photo by Mr Ramanan. The heron has swallowed the fish. Do you see its eye? Now look at the next picture.
No, its not a case of removing "red eye", its the heron's nictitating membrane having covered the eye! Photo by Mr RamananClick on the picture and zoom in, and take a close look. This thin protective membrane is an extra protection that birds, fish and reptiles have, (we dont). This translucent third eyelid closes and opens horizontally across the eyeball, clearing dust, moistening the eye, protecting it in some cases from extreme conditions.
So, for example, owls while out hunting would keep this membrane closed and eyelids opened, so as to keep their eyes moist for better vision, but (quite literally) keeping their eyes open for that scurrying mouse or hopping frog.
It seems that the little pink bit of membrane we have in the corner of our eyes is a vestigial nictitating membrane.
The nictitating membrane definitely an interesting concept!
ReplyDeleteGlad we have got rid of the nictitating membrane, Flowergirl. I don't want to look scarier than I do right now with red eyes. Hope you are enjoying the Tests.
ReplyDeleteI remember first reading about the nictitating membrane in Arundhati Roy's God of Small Things, of all things!
ReplyDelete"Nictitating membrane, she remembered she and Estha once spent a whole day
saying. She and Estha and Sophie Mol.
Nictitating
ictitating
ctitating
itating
tating
ating
ting
ing"
Interesting indeed, Trails of a Traveler.
ReplyDeleteHa ha, Amila, true! We would all look very scary. The timings dont allow for live viewing of the tests sadly. But the Indian batting line up is making heavy weather of things I must say.
Kamini, I had forgotten this from A Roy's book!