These days, lots of people get their exercise at gyms and health clubs, oftentimes by walking or running on treadmills–that is to say, running without going anywhere. If you’ve ever been on a treadmill for some time and then suddenly stepped off it, you’ve probably experienced the weird sensation that you are suddenly moving much faster than you think you should be.
Varicose veins in the legs occur when the valves in a vein near the surface of the skin malfunction. Valves usually keep blood from flowing backwards in the vein once it’s been pumped towards the heart.
Most birds you see standing on only one leg are doing an impressive balancing act while tucking the second leg into their feathers. This is much easier to recognize in large birds, such as flamingos, but the behavior itself is common to most birds.