Reindeer Change Their Eyes for Summer and Winter, Study Finds James Owen for National Geographic News March 13, 2007 Reindeer have a different set of eyes for summer and winter, a new study suggests. Scientists say the animals change their eye color and structure with the seasons in Arctic regions where permanent summer sunlight is replaced by 24-hour darkness in winter. The visual alterations appear to be an adaptation to deal with polar light extremes, according to the researchers from Norway and the U.K., who add that the phenomenon has never before been recorded in mammals. The researchers studied reindeer...