From another wildlife program I caught last week:

If you look very, very carefully at the individual scales on a crocodile hide, you will see what appears to be a black dot, rather large, within each scale. Those black dots are called 'mechanoreceptors' and they allow the croc to sense the movement of prey a hundred or more feet away. Amazing. The narrator pronounced the receptor term this way:

MEH-cuh-no-rih-SEP-tors

He also mentioned chemoreceptors in the croc's mouth that enabled to croc to sense the precise position of the prey it was after once it came in close for the kill. Flavor-based reception, I suppose.