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  • Are you familiar with the word symbiosis?

  • It's a fancy term for a partnership between two different species,

  • such as bees and flowers.

  • In a symbiosis, both species depend on each other.

  • I want to tell you about a remarkable symbiosis

  • between a little bird, the Clark's Nutcracker,

  • and a big tree, the Whitebark Pine.

  • Whitebark grow in the mountains of Wyoming, Montana and other western states.

  • They have huge canopies and lots of needles,

  • which provide cover and shelter for other plants and animals,

  • and Whitebark feed the forest.

  • Their cones are packed with protein.

  • Squirrels gnaw the cones from the upper branches

  • so they fall to the ground,

  • and then race down to bury them in piles, or middens.

  • But they don't get to keep all of them;

  • grizzlies and black bears love finding middens.

  • But there's more to a symbiosis than one species feeding another.

  • In the case of the Clark's Nutcracker, this bird gives back.

  • While gathering its seeds, it also replants the trees.

  • Here's how it works: using her powerful beak,

  • the Nutcracker picks apart a cone in a treetop,

  • pulling out the seeds. She can store up to 80 of them in a pouch in her throat.

  • Then she flies through the forest, looking for a place to cache the seeds

  • an inch under the soil in piles of up to eight seeds.

  • Nutcrackers can gather up to 90,000 seeds in the autumn,

  • which they return for in the winter and spring.

  • And these birds are smart. They remember where all those seeds are.

  • They even use landmarks on the landscape --

  • trees, stumps, rocks --

  • to triangulate to caches buried deep under the snow.

  • What they don't go back and get, those seeds become Whitebark.

  • This symbiosis is so important to both species

  • that they've changed, or evolved, to suit each other.

  • Nutcrackers have developed long, tough beaks

  • for extracting seeds from cones,

  • and Whitebarks' branches all sweep upwards

  • with the cones at the very ends, so they can offer them to the Nutcrackers as they fly by.

  • Now, that's a symbiosis:

  • Two species cooperating to help each other for the benefit of all.



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TED-ED】共生。種の協力の意外な物語 - デイビッド・ゴンザレス (【TED-Ed】Symbiosis: A surprising tale of species cooperation - David Gonzales)

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    VoiceTube に公開 2021 年 01 月 14 日