6/23/2016 4:01:55 PM
Bear Tracker Update
It's late June, which means that the Hudson Bay polar bears on our online Bear Tracker must soon return to land as the sea ice melts away for the summer. When they return to land will vary by bear and sea ice patterns. Where they ultimately choose to rest on land for the summer is impossible to predict, though we can make some informed guesses.
Many bears return to the same general region each year, a pattern we call site fidelity. These may be the same areas their mothers brought them to as cubs, though this is hard to know. Also, females tend to stay more inland (especially if they have cubs) and males tend to stay closer to the coast, but this is not a hard and fast rule.
During the ice-free season, Hudson Bay polar bears will spend about three to four months on land waiting for the sea ice to return. To keep going, they rely on energy from the (hopefully) ample supply of body fat that they accumulated over the winter from eating seals.
While on land, polar bears snack on kelp, berries, eggs, and maybe even some caribou (or dead, washed-up marine animals for very lucky bears!), but terrestrial foods don't pack the same caloric punch as marine mammal prey. Each bear loses approximately one to two pounds a day while onshore. That's why it's important that the summer's break-up period is not early and that the fall's freeze-up season is not late.
Climate change is impacting the Hudson Bay system in different ways and one consequence is less predictable sea ice patterns. Hudson Bay sea ice started to break-up in early June in the northwest and western regions; scientists are seeing the collared Western Hudson Bay females respond by starting to head closer to home over the last couple weeks. We hope the remaining break-up goes slowly and gives the polar bears extra time to hunt seals before they undergo their summer fast.
We won't know how Hudson Bay bears fared hunting this past winter until later this summer and fall, but we will be watching them on the Bear Tracker to see where and when they return to land in the next month or two. Please join us in hoping for a late sea ice break-up season and in taking action to save our sea ice by celebrating Arctic Sea Ice Day with us on July 15th.