On returning to England, Darwin and an ornithologist associate identified 13 species of finches that he had collected on the GalÃ¡pagos Islands. This was puzzling since he knew of only one species of this bird on the mainland of South America, nearly 600 miles to the east, where they had all presumably originated.
To get the most out of a nap, follow these tips: 1  Keep naps short. 2  Aim to nap for only 10 to 30 minutes. 3  The longer you nap, the more likely you are to feel groggy afterward. 4  Take naps in the afternoon.
Caffeine requires 20 or 30 minutes to take effect, so it will kick in just as you're waking. Naps of up to 45 minutes may also include rapid eye movement (REM) sleep, which enhances creative thinking and boosts sensory processing. Limit your nap to 45 minutes or less, if you need to spring into action after dozing. Otherwise, you may drift into slow-wave sleep. Waking from this stage results in sleep inertia, that grogginess and disorientation that can last for half an hour or more. But you might want to take a long nap, at least 90 minutes.