This composite image of brain scans shows two traits of a highly impulsive individual. The cool colors in the midbrain are indicative of a decrease in dopamine receptor levels while the warm colors show elevated levels of dopamine in a different part of the brain called the striatum.
Joshua W. Buckholtz and David H. Zald
Scientists studied the Manduca sexta caterpillar under X-ray and found that when caterpillars walk, their guts move forward first, followed by the rest of their bodies in a rippling movement.
Ted Kropiewnicki/Tree of Life Web Project