Scientists have uncovered the neurological basis for the midnight feast fetish!
Most animals can be trained, when food is lacking, to over-ride their natural sleep wake cycle to time their awakening for when food is available.
But Patrick Fuller and Clifford Saper, writing in this week's Science, have now found that mice lacking a key genetic cog in their brains' bodyclocks cannot do this. And when the researchers replaced the gene in the part of the brain known to contain the body clock, although the animals could go to sleep and wake up at normal times, they still couldn't learn to wake up for food. Until, that is, the researchers added a copy of the gene to a different region of the brain called the dorsomedial nucleus, which is in the hypothalamus.
Once they did this the animals were once-again able to arrange their sleep around mealtimes.
This second food-linked clock is critical for small animals, say the researchers, because they burn energy so rapidly that finding food quickly can be a matter of life and death. But, at the same time, perhaps it could also explain holiday jetlag, especially if they don't feed you on the aeroplane.