Forget meteorite strikes and global cooling - the dinosaurs were killed off by a lack of proper kip, according to Niels Rattenborg of the Max Planck Institute for Ornithology.
And it wasn't because they were too knackered to run away from extinction-causing threats, either - they apparently didn't survive "because their reptilian sleeping patterns meant their brains did not learn new skills properly", as the Scotsman puts it.
Specifically, reptiles can't get a proper night's zeds and therefore don't experience "slow wave sleep, the type of sleep believed to be responsible for boosting memories, especially those connected to performing new tasks".
Mammals and birds suffer no such deprivation, thereby benefiting from the "enhancements in both learning and physical performance" which slow wave sleep promotes by closing down those parts of the brain which have "acquired new skills, thereby allowing this learning to become consolidated without interruption".
The upshot of all of this is that as the Earth's climate changed, the poor old dinosaurs weren't able to learn enough "new tricks" to muddle on, the theory claims.
Hmmmm. Regarding birds and mammals, the research does point to one interesting thing: if both experience slow wave sleep, they must have evolved this ability independently, coming as they do from different evolutionary lines, with our flying friends being more closely related to modern, shattered reptiles.
Niels Rattenborg's paper is published in the Brain Research Bulletin. ®