Labor of Love: Are these circles in the sand the work of some underwater aliens? The mystery of these elaborately crafted circles discovered by diver Yoji Ookata off the coast of Japan, has been solved. Spanning ~6.5 feet in diameter, they turned out to be the painstaking work of a tiny species of puffer fish. The male spends days ruffling the sand, decorating it with crushed shells, using only his fin as tool. The groovier the circle, the more females it attracted, to mate with and lay eggs in the center.
• As if puffer fish were not cool enough already! Considered the most poisonous vertebrate, second only to the golden poison frog, puffer fish (Fugu) are considered a culinary (if risky) delicacy.
• Tetrodotoxin is deadly, up to 1,200 times more poisonous than cyanide. There is enough toxin in one puffer fish to kill 30 adult humans, and there is no known antidote. The toxin works by targeting voltage gated sodium channels that are needed to fire neurons and trigger muscle contraction. Death usually occurs because the victim’s diaphragm is paralyzed so breathing stops.
• Highly elastic stomachs allow the puffer fish to quickly swallow huge amounts of water (or air) and transform into a virtually inedible ball several times their normal size.
Puffer Fish photo by Chris Laughlin from Nat. Geo.