What size wingspan would a polar bear need...?

Question

..to fly?

Answer 1

Well, the critical wing load for most birds is around 5 lbs/sq ft (25 kg/sq m) - this is the minimum area needed for a bird to achieve lift.

An adult male polar bear can be around 1000 lbs.  Assuming the wing was about 5 feet wide, that would give a wingspan of 200 feet (each wing being about 100 feet long).  That's about 4 times longer than the largest flying critter ever known, the pterosaur Quetzlcoatlus.

Of course, that ignores the extra weight that two 100 foot wings would add to the bear.

It also presumes that the bear has flight muscles with sufficient power to flap those wings - which in truth it does not, nor does it have the skeletal anatomy to attach such flight muscles.

In total, it would probably be easier to teach the polar bear how to build a helicopter than it would be to genetically engineer one capable of flight.