Yes, evolution - survival of the not eaten one. Intersting, that deep in ocean waters, where there is eternal darkness, there is active life near hot water volcanic wents. There are bacteria, plankton, shrimps and even big worms (some 10 ft long) eating each other. Due to lack of light none has eyes. But almost all have thermal radiation detectors you may call "eyes" which are sensitive to weak infrared radiation around.

Also, if you bring those creatures who live comfortably in 150-170+ F water to the " very cold" 100 F water, they die almost instantly.