Northumberland's Chillingham cattle were once domesticated, but now roam free.
诺森伯兰郡奇灵厄姆的牛曾经被人驯养，但是现在它们自由生活。
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Northumberland’s Chillingham cattle were once domesticated, but now roam free. And they offer a unique opportunity for study.
在诺森伯兰，切宁纳姆牛曾经是家养的，但是现在它们可以在户外漫游，并且它们提供了一个特殊的研究机会。
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Thanks to Darwin, records on Chillingham cattle go back 150 years, and show a breeding response to climate change resulting in more winter calf deaths.