Riddle: I have four of these, With matching extremities. They can do many things, And hardly ever bring me pain. Unless I stick them with a pin, Or burn them sometimes when... What is it that I can wiggle at will? And use in other means still?
Riddle: NASA was considering sending canaries into space to study them under zero gravity. The project was scrapped when someone realized that in spite of having sufficient water supplies, they could die of dehydration within a few hours. Why?
Answer: Birds, unlike humans, need gravity to swallow. Humans can swallow even while hanging upside down.