086 / / JANUARY 2017
trictly speaking, flying squirrels- scientifically known as
Pteromyini or Petauristini – cannot
really fly, and are gliders not flappers.
Glides of up to 90m have been measured, but not one
of this tribe of 43 species has wings or feathers.
To understand how flying squirrels evolved, some
18-20 million years ago, you just have to think of
normal squirrels leaping from tree to tree. Occasionally
a squirrel would be born with slightly more skin under
its arms, and this gave it a very small advantage when
travelling around the forest. It could leap a bit farther,
get to difficult-to-reach food, and make its escape
from predators. Gradually, as natural selection
favoured these better-adapted individuals and their
descendents, the flying squirrels of today evolved.
Most flying squirrels live in the jungles of Asia,
where being able to glide from tree to tree is helpful
for finding food and evading predators, which include
cats, raccoons and coyotes. The biggest threat they
face, however, is destruction of their habitat.
The largest of them is the woolly flying squirrel
(Eupetaurus cinereus) found in Pakistan, which
can grow up to 60cm in length (minus its tail). The
smallest, pygmy flying squirrels, are found in the
tropical rainforests of Borneo and Malaysia. They
measure less than 10cm long and look like large
butterflies flitting through the treetops.
Two species (Glaucomys sabrinus and Glaucomys
volans) live in North America, while the Siberian flying
squirrel (Pteromys volans) is native to parts of northern
Europe. In Helsinki, where the Siberian flying squirrel
is protected, there are now 25 nests in the city’s
wooded Central Park, compared to just six in 2014.
Turn the page for some more amazing facts about
this extraordinary animal.S
Easy glider
Daredevil
There are birds that
can’t fly and there are
mammals that can –
and the flying squirrel
has to be one of the
most incredible. Diana
McAdam explains
how these agile
rodents took to the air