Do lizards dream of scaling walls and catching flies?

Well, possibly. Scientists have discovered that reptiles’ sleeping habits are much more similar to our own than we previously thought.

No, it’s nothing to do with David Icke’s theory of the Reptilian Elite (we think) but a study of five Australian bearded dragons.

Scientists watched them while they slept and concluded that they may have REM sleep like us – which could prompt a fundamental reassessment of how sleep evolved.

It turns out humans may not be so special after all, as previously the theory was that only mammals and birds had this type of sleep.

For the first time, scientists said they had proof that reptiles had the stages of sleep known as rapid eye movement (REM) and slow-wave sleep.

REM sleep is the phase when humans have dreams.

Neuroscientist Gilles Laurent, director of the Max Planck Institute for Brain Research in Germany, said he wasn’t sure what lizards would ‘dream’ about.

‘I’d speculate that those dreams are about recent notable events: insects, maybe a place where there are good insects, an aggressive male in the next terrarium, et cetera,’ he said.

‘If I were an Australian dragon living in Frankfurt, I’d be dreaming of a warm day in the sun.’

The discovery suggests the sleep stages evolved a lot earlier than previously thought, from a common lizard-like ancestor of mammals, birds and reptiles between 300 million and 320 million years ago.

To measure the lizards’ dreams, scientists placed probes inside their brains to measure activity.

While people experience four or five cycles between slow wave and REM a night, lizards cycled much more quickly, averaging 350 cycles each lasting around 80 seconds.

Some of the telltale signs of these sleep stages, seen in the brain’s hippocampus in mammals, were found in a more primitive brain region, the dorsal ventricular ridge, in the lizards.

Some scientists had hypothesized REM and slow-wave sleep might be linked to warm-bloodedness and evolved independently in birds and mammals.

The research was published in the journal Science.

Source:
courtesy of METRO

by Jen Mills

If you have any stories or news that you would like to share with the global online community, please feel free to share it with us by contacting us directly at [email protected]