Holding a baby can change its DNA.  Studies show children who have low physical contact as infants end up with DNA cells that are less mature than usual, which can result in delayed growth and development. This means the effects of denying physical affection to babies aren’t just behavioral- they’re genetic.  (, , )

Plants know when they’re being eaten.  There are certain plants that emit toxins as a defense mechanism in response to the sounds of caterpillars chewing – even when the sound is played as a recording. Researchers hope this discovery can someday help reduce the use of man-made pesticides.  (, , )