Q. Do lizards dream like people do?

A. Some species of lizards do have two sleep phases, one resembling the dreaming phase of human beings, other mammals and birds.

In 2016, a study of the central bearded dragon, Pogona vitticeps, found slow-wave and rapid-eye-movement states that cycled back and forth in 80-second increments over sleep periods of six to 10 hours.

In other animals, slow-wave sleep is usually described as deep, dreamless sleep, while rapid eye movements are linked to shallower sleep and dreaming.

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Recently scientists in France collected data on brain activity, heart rates and behavioral patterns, including eye movement, in the sleeping Argentine black-and-white tegu (Salvator merianae). The scientists also documented two sleep states, suggesting that the animals do experience something like R.E.M. sleep.