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(单词翻译)
Oxpeckers riding on rhinoceroses2 feast on ticks, and their calls warn the nearsighted herbivores about approaching humans.
Full Transcript3
Black rhinos4 have terrible eyesight. Even so, these giant African herbivores easily fend5 off hungry lions and hyenas6.
“Their basic body plan has proved to be good enough to survive on a savanna7 full of large predators8, being very large, thick-skinned—big, rapierlike horns.”
Victoria University of Melbourne behavioral ecologist Roan Plotz. But those protective traits are no match for humans with guns. Today the species is critically endangered largely due to poaching. But the rhinos may have an unlikely ally against poachers: the red-billed oxpecker. The chatty, sociable9 birds often hang out on the backs of rhinos, feasting on parasitic10 ticks.
“And actually, research has shown that the tick is the favorite diet of an oxpecker. And if they feed on ticks, that is a good thing.”
The birds also get nutrients11 by picking at sores on the rhinos’ bodies. Plotz suspected that the rhinos put up with this indignity12 because the oxpeckers make loud alarm calls whenever they see humans approach—giving the rhinos an early warning to flee.
“And it’s sort of a distinctive13 rattling14, a bit hissing15 sort of sound.”
[CLIP: Alarm call]
To test whether the oxpeckers do, in fact, act as noisy lookouts16, Plotz and his team implanted radio transmitters in the rhinos’ horns. This didn’t hurt the rhinos and allowed the researchers to track the animals ...
“And approach them undetected, when the oxpeckers were on the back and when the oxpeckers were not on their backs, to get an idea of if the birds do alert them and if the rhinos do listen.”
The researchers found that rhinos without oxpeckers detected an approaching human only 23 percent of the time, at an average distance of 27 meters. But when oxpeckers were present, the birds alerted the rhinos 100 percent of the time. And they detected the human 61 meters away on average. And the more oxpeckers on the scene, the greater the detection distance—which means the earlier the warning.
“Which makes sense because the more eyes you have on your back, looking out for you, the more chance that they can pick up anything coming. What we think is going on, fundamentally, is that the rhino1 is eavesdropping17 on the oxpecker alarm call, there can be no doubt of that. There's a really strong antihuman benefit to listening to oxpecker alarm calls.”
The study is in the journal Current Biology, with oxpecker recording18 by Tiffany Plantan of the University of Miami. [Roan D. Plotz and Wayne L. Linklater, Oxpeckers help rhinos evade19 humans]
Plotz thinks the oxpeckers may have evolved their sentinel behavior because it protects their convenient food source. And the more lookouts, the better in what seems like a win-win for both species: the birds thrive and the rhinos survive.
[The above text is a transcript of this podcast.]
1 rhino | |
n.犀牛,钱, 现金 | |
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2 rhinoceroses | |
n.钱,钞票( rhino的名词复数 );犀牛(=rhinoceros);犀牛( rhinoceros的名词复数 );脸皮和犀牛皮一样厚 | |
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3 transcript | |
n.抄本,誊本,副本,肄业证书 | |
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4 rhinos | |
n.犀牛(rhino的复数形式) | |
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5 fend | |
v.照料(自己),(自己)谋生,挡开,避开 | |
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6 hyenas | |
n.鬣狗( hyena的名词复数 ) | |
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7 savanna | |
n.大草原 | |
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8 predators | |
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面) | |
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9 sociable | |
adj.好交际的,友好的,合群的 | |
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10 parasitic | |
adj.寄生的 | |
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11 nutrients | |
n.(食品或化学品)营养物,营养品( nutrient的名词复数 ) | |
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12 indignity | |
n.侮辱,伤害尊严,轻蔑 | |
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13 distinctive | |
adj.特别的,有特色的,与众不同的 | |
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14 rattling | |
adj. 格格作响的, 活泼的, 很好的 adv. 极其, 很, 非常 动词rattle的现在分词 | |
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15 hissing | |
n. 发嘶嘶声, 蔑视 动词hiss的现在分词形式 | |
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16 lookouts | |
n.寻找( 某人/某物)( lookout的名词复数 );是某人(自己)的问题;警戒;瞭望台 | |
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17 eavesdropping | |
n. 偷听 | |
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18 recording | |
n.录音,记录 | |
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19 evade | |
vt.逃避,回避;避开,躲避 | |
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20 bard | |
n.吟游诗人 | |
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