Natures wonders: blind shrimp sense light (Introduction)

by David Turell , Tuesday, March 29, 2016, 20:14 (2942 days ago) @ David Turell

They live in caves, are frozen in winter but survive and sense light and move to darkness:-https://www.newscientist.com/article/2082258-eyeless-cave-shrimp-senses-light-and-can-live-frozen-in-ice/-"Although there are examples of animals that can survive being frozen solid, few, if any, have been found in caves. “Cave dwellers are typically not adapted to freezing,” says Espinasa.-***-"The ice caves, however, are different. They are tectonic, having been formed by faults and cracks in the rock. Snow and cold air enter the caves through openings at the top and are then unable to escape, creating a refrigerated environment in which some of the walls and floors become covered in solid ice.-"Experiments in both the field and lab showed that the shrimp were able to survive and return to swimming normally after being frozen in solid blocks of ice for several hours (see video below).-"Animals generally survive a deep freeze by filling their body with substances - such as glycerol, a variety of sugars or amino acids - that lower the freezing point of the water inside them, and prevent ice crystals from forming and destroying their cells.-***-"His team also found in tests that the eyeless shrimp could distinguish between light and dark, with the creatures being drawn to the dark - a feature known as scotophilia.-"Espinasa doesn't know what they use instead of eyes, but early results suggest that the light-detecting structures may be on their heads."-Comment: Life's creatures can adapt to anything. The antifreeze we use is propylene glycol, a glycerol relative. Fish use it in the Arctic, something noted here before.