Photo by Rick Geary

It’s torpor, not really sleep.

Dear Matthew: Do insects sleep? Are there any regular animals that don’t? I guess I mean mammals, birds, and reptiles. — Carolyn Kurtz, Valley Center

Well, personally, I haven’t gotten a solid eight hours since Rush Limbaugh hit the air. But then neither has a bug. They space out, they go sort of limp and listless, but insects don’t really catch Zs the way we do. Nobody’s yet recorded any REM sleep in a beetle. Bugs are pretty basic machines; air temperature and light control is a lot of what they do. When the lights go down and the temp drops, the metabolism of bugs with day jobs slows way down, and they crawl into a crevice or hide under a leaf until it warms up again. It’s torpor, not really sleep. Some bugs can torpor their way through a whole winter, if necessary. That said, you’d never guess fruit flies are leading the march toward a better night’s rest for all of us. Scientists have identified the gene that resets a fruit fly’s biological clock and zaps it into action when you flash bright lights in its face. That, apparently, is great progress and could somehow end the heartbreak of jet lag and insomnia. Science staggers on.

Birds, reptiles, and most fish lapse into a semicomatose doze when it gets dark but don’t really sleep the way humans do. Whales “surface sleep,” moving their flukes slowly, bobbing up and down to breathe periodically. When a dolphin closes its eyes for a snooze, half its brain takes a break while the other half keeps it from drowning. Seals and sea lions can sleep while they float and also (for 15 minutes or so) on the sea floor. Elephants are so huge they must eat pretty much constantly and only catch a few hours of sleep a day. Cows and sheep also only catnap. On the other hand, cats spend half their lives in dreamland.