Winter tick infestations are causing catastrophic welfare harm and population decline in moose across North America as climate change extends tick survival and reduces mortality.
Winter tick infestation causes prolonged and severe suffering in moose. The blood loss from tens of thousands of feeding ticks causes progressive anemia, weakness, and hypothermia as hair loss from constant rubbing destroys insulation. Calves carrying heavy tick burdens may be too weakened to find food and die from starvation before spring. The suffering lasts for months — from autumn when ticks attach through spring when they drop. The climate change driver of this welfare crisis makes it one of the clearest examples of how global warming translates into individual animal suffering at enormous scale across affected populations.