WEDNESDAY, Dec. 14, 2016 (HealthDay News) -- Santa may need more than nine reindeer to pull that sleigh around the world this year because reindeer are getting smaller, a new study shows.
Researchers suggested that reindeer are shrinking because climate change is disrupting their food supply.
Scientists reported that reindeer on Svalbard, a Norwegian archipelago, have become smaller and lighter over the past 16 years. During that same time, the Arctic has been affected by warming in the summer and winter.
The study authors came to their conclusions after reviewing statistics regarding the reindeer they measure and weigh each year, starting with 10-month-old calves. From 1994 to 2010, the average adult reindeer weight fell by 12 percent, from 121 pounds to 106 pounds, the researchers found.
"In Svalbard, snow covers the ground for eight months of the year, and low temperatures typically limit grass growth to June and July. But as summer temperatures have increased by 1.5 degrees Celsius [or 2.7 degrees Fahrenheit], pastures have become more productive, allowing female reindeer to gain more weight by the autumn and therefore conceive more calves," explained study leader Steve Albon in a news release from the British Ecological Society.
Albon is an ecological sciences researcher at the James Hutton Institute in Aberdeen, Scotland.
But in the winter, it's been raining more because it's warmer. This produces frozen snow, which covers up food from reindeer, who starve in some cases or abort their calves, Albon said.
There's another factor, he noted: Reindeer numbers have doubled over the past 20 years, and there could be more competition for food.
"The implications are that there may well be more smaller reindeer in the Arctic in the coming decades but possibly at risk of catastrophic die-offs because of increased ice on the ground," Albon said.
The findings were presented Monday at the British Ecological Society annual meeting in Liverpool, England. Findings presented at meetings are generally viewed as preliminary until published in a peer-reviewed journal.
For more about reindeer, visit the San Diego Zoo.