Placeholder Image

字幕列表 影片播放

  • This episode of Deep Look is brought to you by CuriosityStream.

  • For over 300 million years, these lethal hunters have ruled the skies.

  • They're the order Odonata.

  • That's dragonflies and damselflies to most of us.

  • Before the dinosaurs even existed, they had a two-foot wingspan, like a small hawk.

  • Today they're more modest in scale, but no less deadly.

  • Take their eyes.

  • Each tiny hexagonal cell picks up light from a different direction, which gives dragonflies

  • an almost-360-degree range of vision.

  • Four wings help them hover, or turn on a dime.

  • That means this hunter rarely misses.

  • The weird thing is Odonata spend most of their lives in a place where these killer piloting

  • skills don't help.

  • This is where their mothers lay their eggs.

  • When they hatch, the babiescalled larvae or nymphsspend months or years underwater.

  • Their wings are still growing, so they aren't any help in scoring a meal

  • like this tasty mosquito larva.

  • It's a larva-eat-larva world down here.

  • Did you see that?

  • Let's slow it down.

  • The nymph has a killer lip, called a labium.

  • Remind you of this creepy thing?

  • For this skimmer nymph it's shaped like a spork.

  • Only dragonfly and damselfly nymphs have this special lip.

  • This kind of dragonfly nymph, a darner, has an extra surprise.

  • There's a pair of pincers right at the end.

  • It all happens in a fraction of a second.

  • Think of the lip as a knife, fork and plate all rolled into one.

  • When the meal is over, it folds up neatly, ready for the next occasion.

  • These baby skeeters don't stand a chance.

  • And that's good for us.

  • Let's hope it stays this way for a few million more years.

  • This episode is brought to you by CuriosityStream, a subscription streaming service that offers

  • documentaries and non-fiction titles from some of the world's best filmmakers, including

  • exclusive originals.

  • Want to learn more about dragonflies and other insects?

  • CuriosityStream's video seriesInsect Dissectioninvestigates how insects evolved

  • to dominate our world.

  • To get unlimited access and your first two months free, sign up at curiositystream.com/deeplook

  • and use the promo code deeplook during the sign-up process.

  • Hi there.

  • It's Lauren again.

  • If you're curious about the history of dragonflies, check out Eons, the newest science channel

  • to join the PBS Digital Studios network.

  • This week, Eons travels back in time to the age of giant insects.

  • And make sure to visit PBS Infinite Series, a show about the mathematics that underpins

  • everything in this puzzling, yet fascinating, universe.

  • Thanks for watching.

This episode of Deep Look is brought to you by CuriosityStream.

字幕與單字

單字即點即查 點擊單字可以查詢單字解釋

B2 中高級 美國腔

蜻蜓寶寶的嘴會讓你做惡夢|深度觀察 (A Baby Dragonfly's Mouth Will Give You Nightmares | Deep Look)

  • 19 0
    LEO 發佈於 2021 年 01 月 14 日
影片單字