Minnesota wildlife researchers say they are getting a better understanding of what's killing the state's moose and causing a major population decline...

In summer, he said, moose can go to ponds or streams to cool down when they get too warm. In winter, moose can only lie in the snow and shade, which offers less cooling, [Minnesota Department of Natural Resources Glenn] DelGiudice said. When air temperatures reach 23 degrees in winter, moose can begin to experience heat stress, increasing their metabolism, heart rates and respiration. "If the effects of climate change are negatively affecting the nutrition of moose in winter, it could clearly make them compromised and more vulnerable to disease and other things," he said