Who knew breathing could be so beautiful?
This outstanding animated GIF, created by designer Eleanor Lutz for her science illustration blog Tabletop Whale, shows three different ways that animals exchange gases with their environments, with fresh, oxygen-rich air shown as yellow, and deoxygenated air shown as red.
You might be pretty familiar with the type of breathing done by humans (and other mammals). By flexing and unflexing the diaphragm, we draw air into our lungs, where it inflates tiny air sacs called alveoli and allows oxygen to pass into the blood. At the same time, excess carbon dioxide passes in the opposite direction, and gets exhaled when we breathe out.
Birds are a bit different. The same sort of gas exchange takes place in the lungs, but they have several independent air sacs that can briefly hold air. This means they can force entirely fresh, oxygen-rich air into their lungs (unlike in mammals, where fresh and stale air mix slightly), so they can effectively breathe at higher altitudes.
Finally, grasshoppers — along with all other insects — have a dramatically different system. Instead of separate circulatory and respiratory systems, they simply have a single substance called hemolymph (instead of blood) that picks up oxygen from a series of different air sacs and carries it throughout the body.
