Page 57 - BBC Wildlife Volume 36 #04

AGENDA SHINING A
ANALYSIS
SPOTLIGHT ONTO
THE BALKANS’
KILLING FIELDS

O THE HEROES TACKLING BIRD
ii UNDERSTAND THE ISSUES | BE PART OF THE SOLUTION HUNTING IN CROATIA AND SERBIA P64

Called ice bears in
some cultures, polar
bears are dependent
on hunting seals on
the sea ice to survive.

ICE BEAR FACING ENERGY TRAP

POLAR BEARS ALREADY FIND IT HARD TO CATCH ENOUGH PREY – AND HOW WILL CLIMATE CHANGE AFFECT THAT?

olar bears use up far more Lead researcher Anthony Pagano and his colleagues doesn’t suddenly provide new
energy while hunting than Pagano, of the US Geological calculated that a female bear hunting opportunities.
Pexpected, new research Survey (USGS), says the biggest in early spring would need to “By November, seals are not
has revealed, leading to fresh factor was the bears walking catch one adult ringed seal, three as reliant on sea ice. They’re just
concerns about the species’ vast distances looking for seals’ subadults or 19 new-born pups making holes to breathe through,
long-term viability. breathing holes, which is how every 10-12 days in order to meet and they are more diligent and
Scientists attached GPS and most of them catch their prey. their energy requirements. less naive,” Pagano says.
video-equipped collars and “Some of the bears But, in fact, they “As sea ice becomes
loggers with accelerometers to were moving 250km DID YOU must really catch increasingly short-lived annually
nine female bears for up to 11 over the course of 10 more than this during [because of the impacts of
days over two consecutive years days,” Pagano says. KNOW? the key hunting climate change], polar bears are
to find out how much effort “It’s not unusual for period of late March likely to experience increasingly
Polar bears sit
they expended during the key polar bears to cover and wait by seals’ to early July, before stressful conditions and higher
hunting season of early April. big distances, but now breathing holes the sea ice starts to mortality rates,” the study
90 per cent of the
The results showed the bears’ we can quantify it – break up and deny concludes. James Fair
time while hunting
metabolic rates were 60 per cent and it was the biggest – only for 10 per them access to + FIND OUT MORE
factor [in their energy
seals on which they
higher than previously assumed,
Darrell Gulin/Getty and four of the nine bears lost expenditure].” effort do they depend. Even the Read the paper in Science:
cent of hunting
actively stalk
about 10 per cent of their body
In the paper
refreezing of the sea
their prey.
http://bit.ly/2nuQyak
mass during the study.
published in Science,
ice in the autumn
April 2018 BBC Wildlife 57