Friday Fun Fact!
You are already experts on counter-current exchange and the way in which it allows efficient exchange of heat from veins to arteries. It also allows animals which operate in a low-oxygen environment to maximize the amount of oxygen in the blood using the same principle of running oxygen rich blood in parallel and opposite to oxygen poor blood in order to exchange the gas across vessel walls.
While these geese are certainly the trophy-winners at altitude, they are not the only high flyers out there. An airliner once struck a mallard at 21,000 feet above Nevada. Evidence of pintail ducks and black-tailed godwits have been found at 16,400 feet on a Himalayan glacier. Even the tiny, delicate Monarch butterfly has been sighted at 11,000 feet up in the air.
Next time you see migrating critters passing overhead, take a moment to appreciate what it takes to get them there and the astounding achievements of which they are capable without even flinching.
5 hours ago