 In their southern range, especially near Hudson Bay and James Bay, Canadian polar bears endure all summer without sea ice to hunt from. Here, their food ecology shows their dietary flexibility. They still manage to consume some seals, but they are food-deprived in summer as only marine mammal carcasses are an important alternative without sea ice, especially carcasses of the beluga whale. These alternatives may reduce the rate of weight loss of bears when on land. One scientist found that 71 % of the Hudson Bay bears had fed on seaweed (marine algae) and that about half were feeding on birds like sea ducks, especially the oldsquaw (53 %), common eider, long-tailed duck or dovekie by swimming underwater to catch them. They were also diving to feed on blue mussels and other underwater food sources like the green sea urchin. 24 % had eaten moss recently, 19 % had consumed grass, 34 % had eaten black crowberry and about half had consumed willows. This study illustrates the polar bear's dietary flexibility but it does not represent its life history elsewhere. Most polar bears elsewhere will never have access to these alternatives, except for the marine mammal carcasses that are important wherever they occur.
