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  • [♪ INTRO]

  • On the remote, rocky islands of the North Pacific,

  • you might find a happy-looking little bird.

  • Called the crested auklet, it looks

  • kind of like a cross between

  • a penguin and a quail.

  • They live in big, dense, noisy colonies

  • and go out to the ocean to feed.

  • They also, apparently, smell like tangerines.

  • The smell, which has been described as

  • distinctiveandpungent”, emerges

  • at the beginning of the breeding season.

  • As for what's actually causing it,

  • the smell seems to come from a mix of

  • compounds secreted by a patch of special,

  • hair-like, possibly hollow feathers called

  • wick feathers found on a particular area

  • of skin on their back.

  • They just got a little tangerine patch back there.

  • The mix of compounds is dominated by aldehydes,

  • a kind of chemical that contains a

  • carbon bonded to a hydrogen and

  • double-bonded to an oxygen.

  • As for why, there are two hypotheses.

  • One is that the smelly aldehydes might be

  • a way for the birds to repel parasites like lice

  • kind of like a built-in can of bug spray.

  • Experiments have shown that some of

  • the compounds in the smell can repel

  • or paralyze ticks or lice.

  • The other idea is that it might be

  • some kind of sexual display or some

  • other sort of social signal.

  • During courtship, crested auklets approach

  • potential mates and bury their bill in

  • that patch in what's known as a “ruff-sniff”.

  • And they can definitely smell it.

  • Studies have shown the birds can tell

  • the scent apart from other smells and even

  • appeared to be attracted to it when

  • presented with a smelly fake bird.

  • Which is kind of neat, because for a

  • long time many experts thought birds

  • couldn't really smell things.

  • That idea was debunked by scientists

  • in the 1960's, and that research doesn't

  • have much of anything to do with crested auklets,

  • but as a myth it's had surprising staying power.

  • It might seem kind of funny,

  • but choosing the smelliest mate

  • might have some benefits.

  • If the scent is a parasite repellent,

  • for example, a smelly mate is less likely

  • to pass infestations to their mate or offspring.

  • The smell might also be an indicator

  • of how healthy the animal is in general.

  • Its body has to produce those smelly chemicals,

  • which requires energy.

  • And because all smells eventually fade over time,

  • an animal that depends on cologne to win a mate

  • has to keep making new compounds all the time.

  • Which means it has the energy to burn

  • to make smelly molecules, even though

  • those resources could be used for other,

  • more survival-oriented things.

  • This means for crested auklets, a strong scent

  • might be a way to show that you're not only healthy,

  • but you have the resources to burn.

  • Citrus-scented birds are pretty neat,

  • but they're far from the only

  • fascinating animals out there.

  • If you want to learn about more of them,

  • you might enjoy the documentaries on CuriosityStream.

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  • non­fiction titles from some of the world's

  • best filmmakers, including exclusive originals.

  • Like Animal Builders, which is all about

  • the incredible engineers of the animal kingdom.

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  • [♪ OUTRO]

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B2 中上級

これらの鳥はミカンのような臭いがします (These Birds Smell Like Tangerines)

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    林宜悉 に公開 2021 年 01 月 14 日
動画の中の単語