:I am assuming that snake's pupils will dialate?? The top speck seems to have more of a round pupil than the one below it. Do they get really thin at night and more round during the day??
Yes, they do dialate and constrict. The brighter the light source, usually the more constricted the pupil will be in order to reduce the chance of damage to the retina. At night (ie. low light) the pupils are usually more dialated (full pupil) and during the day more constricted (thin slits). It's pretty much the same premise as in humans. The flash of the camera "usually" causes the thin pupils like the bottom animal. For some reason the animal on top has genetically large pupils that are not as responsive to light.