多虧了達爾文的呼吁，奇靈厄姆牛的記錄持續了150年，如今的分析發現這種牛對氣候變化做出了生育反應，只不過在冬季出生的牛犢死亡率也提高了。CG報道。

Climate change affects seasonal events—spring flowers open earlier, songbirds breed sooner. But what about mammals? A new study documents the effect on a special breed of cows in the U.K.

Northumberland’s Chillingham cattle were once domesticated, but now roam free. And they offer a unique opportunity for study. Because owners started keeping detailed records on them in 1860, due in part to the urging of none other than Charles Darwin. The cattle are thus an excellent source of long-term info on how earlier springs affect what’s called phenology—seasonal lifecycle events.

The Chillinghams can give birth all year, not just spring and summer like most U.K. mammals. And the data show that over the past few decades, there’s been an increase in winter births. Which the researchers correlated to warmer springs the previous year: plants grow earlier, the cattle have more access to nutrition and they conceive earlier.

But winter babies are more likely to die before they turn one. The research was published in the Journal of Animal Ecology. [Sarah Burthe et al., "Demographic Consequences of Increased Winter Births in a Large Aseasonally Breeding Mammal (Bos taurus) in Response to Climate Change]The researchers say that even mammals that breed year round—which should offer protection against seasonal shifts—may still feel the impact of climate change.

—Cynthia Graber