Polar bears could face extinction sooner than predicted according to a new study published by the journal Science. Researchers spent three years studying nine bears with collars on and recording their activity. The results found that the bears were struggling to find food as a result of melting ice and climate change.
Polar Bears’ prey is typically seals, however seals are dependent on sea ice, which is melting as a result of climate change. This means that polar bears are travelling further to find food. The World Wildlife Fund (WWF) found that polar bears are spending 50 per cent of their time looking for food, and are successful less than 2 per cent of that time.
In an extract from the study, the research says: “To remain in energy balance with these elevated metabolic demands, polar bears have evolved hunting tactics to prey on high energy-content prey, such as ringed seals (Pusa hispida), and preferentially feed on their energy-dense blubber.
“Using our measures of daily FMR, we estimated that a solitary female bear on the spring sea ice would on average need to eat either one adult ringed seal, three subadult ringed seals, or 19 newborn ringed seal pups every 10 to 12 days to remain in energetic balance.”
Results showed that bears who killed and ate seals maintained body mass, however those that scavenged or showed no evidence of eating lost body mass. In the 8-11 day period that the bears were monitored, four bears lost 10 per cent of their body mass, with an average loss of 1 per cent per day.
The study concludes by saying: “More than half of the bears in this study lost body mass, meaning that over the period of observation, their energy demand exceeded that gained by consuming prey […] Hence, increases in movement and activity rates mediated by the loss of sea ice habitat are likely to have negative cascading effects on polar bear reproductive success and, ultimately, their populations.”