Polar bears are experiencing deteriorating nutritional condition as sea ice declines reduce access to seal prey during critical spring feeding periods.
Extended fasting on land past the traditional seal-hunting season causes progressive nutritional stress, muscle wasting and immune suppression. Thin females entering maternity dens may produce insufficient milk for surviving cubs. Cubs born to nutritionally compromised females have lower survival rates. The welfare trajectory for polar bears under climate change is one of progressively worsening chronic stress for populations unable to adapt to alternative prey sources.