Moose are dying and scientists want to know why. According to this article from The New York Times, several different moose populations across North America are showing alarming declines and the reasons remain a mystery. Reseachers in one Minnesota study tracking the state’s moose decline have radio-collared 116 moose of which 85 have died over the past seven years. After accounting for death by wolves, hunting, car and train collisions and other causes, there are still 49 dead moose whose cause of death is unknown.

The Minnesota researchers as well as many scientists studying other declining moose populations hypothesize that climate change may be killing moose. Not only do winter temperatures above 23 degrees stress moose, but increased humidity in the summer and shorter winters can weaken a moose’s immune system.

In New Hampshire, shorter winters mean more winter ticks. Literally thousands of ticks can attach themselves to a single moose with fatally stressful results.