They’re big. They’re white. They’re definitely not cuddly. They definitely are incredible.
Polar bears live up in the Arctic where they are well adapted to the chilly (well… mostly chilly) temperatures of the air and sea. Able hunters, polar bears are mostly carnivorous. Their prey of choice—seals, which they hunt by lying in wait at seal breathing holes, waiting for hours for the chance to grab an unsuspecting seal. Sometimes polar bears will even sneak up on seals resting on the ice, slowly creeping until it is close enough to rush in.
No wonder polar bears have their own day… and that day is today!
There are many things we know about polar bears, and many things we have yet to discover. Let’s take a peek at some of the beary interesting discoveries made about our polar friends over the past year.
Polar bears and brown bears got intimate
Polar bears diverged from brown bears some 500,000 years ago, but one study by Dr Ming-Shan Wang and colleagues suggests that polar bears and brown bears were getting it on during the last interglacial (130,000-115,000 years BP). This isn’t the only time polar and brown bears met since their divergence. Other DNA analysis suggests the bears hybridized at least four times between 15,000 and 25,000 years ago. Apparently in each ‘event’ gene flow primarily went from the polar to the brown bears. In fact, as much as 10% of brown bear genome has polar bear ancestry.
Credit: Anne Spratt/Pixabay
Up until 2022, there were only 19 subpopulations of polar bear known to science
There are an estimated 22,000-31,000 polar bears across the Arctic region. Like many other species, the polar bear population actually consists of several genetically distinct subpopulations. Up until last year, scientists had identified 19 polar bear subpopulations, but a 2022 (paywalled) study by Dr Kristin Laidre and colleagues revealed the 20th population, living in souteast Greenland. This subpopulation, the scientists say, appear to be much less reliant on sea ice than other subpopulations. “Conservation of Southeast Greenland polar bears, which meet criteria for recognition as the world’s 20th polar bear subpopulation,” they write, “is necessary to preserve the genetic diversity and evolutionary potential of the species.”
Credit: Leandra Rieger/Pixabay
Climate change means fewer places to den
When it comes to having babies, polar bears’ opt for snow drifts, in which they can create a den and give birth. As this study by Drs Benjamin Mertek and Jon Aars shows, in the European Arctic the sea ice that lets the bears reach these drifts from their hunting grounds is arriving later and later.
So late, in fact, that many of the snow drifts have already melted by the time the bears arrive.
Tall papillae keeping polar bears upright on ice
Life on ice could be a very slippery affair, but not so for polar bears. The secret is in their paws.
Relative to brown and black bears, polar bear paws are smaller. Generally speaking, the smaller the surface area of a paw (or feet, in our case), the less traction you have and the more likely you are to slide. Polar bear paws, however, have a little secret in the shape of papillae.
Polar, black, and brown bear paws are covered in papillae (small bumps), but the papillae on polar bear paws are 1.5 times taller than those on brown and black bears. These taller papillae help increase the “true” surface area of the polar bear’s paws, giving them the traction they need.
Credit: Ted/Flickr (CC BY-SA 2.0)