Nicole Miller-Struttmann at SUNY College in Old Westbury, New York, and her co-workers studied bees at three alpine sites in the Rocky Mountains. Similar to other mountainous habitats around the world, the Rockies have seen a drop in the number of flowers because of warmer temperatures and drier soils. The researchers measured the tongues of 170 bees and found that they have got shorter by an average of about two millimetres since the 1970s in two dominant bee species in that area, Bombus balteatus and Bombus sylvicola.