A 16-year survey on the arctic Norwegian island of Svalbard found the reindeer there have declined in weight by an alarming 12 percent. 

一项对挪威北极区域斯瓦尔巴特群岛长达16年的调查发现，这里的驯鹿体重下降了12%，这一数字让人震惊。

The reduction in average body-mass is being blamed on global warming. 

In research presented lately at a meeting of the British Ecological Society in Liverpool, scientists will explain how rising temperatures are depriving female reindeer of nutrients during important phases of gestation. 

Snow in Svalbard typically covers the ground for eight months of the year, which, combined with low temperatures, limits grass growth to June and July. 

But as summer temperatures have increased by around 1.5℃, pastures have become more productive, allowing female reindeer to gain more weight by the autumn and therefore to conceive more calves.

However, warmer winters have brought with them greater rainfall which freezes when it settles on the snow, thereby locking out the reindeer from the life-sustaining food below.

As a result, female reindeer are becoming starved, causing them to abort their calves or giving birth to much lighter young. 

The average mass of an adult reindeer in 1994, when the survey began, was 55kg, but by 2010 it had dropped to 48kg.