Snippets From Science

• As a wild turkey walks, the movements of its head appear comical – it thrusts the head forward, freezes briefly, retracts the head, then thrusts it forward again, over and over in synchrony with its leg movements. The turkey is one of Nature’s bobble-heads. Scientists are beginning to understand the significance of  “bobbling.” Turkeys don’t have good depth perception, since their eyes are set on the sides of their heads. As the head thrusts forward, the eyelids close, then instantaneously open at the end of the thrust. This allows the bird to change the focal point of its “gaze,” and its visual field is briefly stabilized despite the motion of its body. Other birds, such as chickens and pigeons, also use thrusting head movements to enhance depth perception and remove motion blur.

• The Bombardier Beetle has evolved a novel defense mechanism. Early naturalists gave the beetle its name when they discovered that a loud popping sound accompanies the release of a cloud of noxious spray from an opening near the tip of its abdomen. The tip has a nozzle that the beetle uses to aim the spray at an intruder, including humans. The spray can travel up to 8 inches. The foul spray is generated in the beetle when two highly reactive chemicals are mixed, then triggered by any enzyme that causes the boiling hot mixture to explode from the beetle’s posterior. So not only is the spray foul-smelling, it can also burn the target animal. (Gullan and Cranston, The Insects) Crush an Asian Beetle or a “Stinkbug” in a Kleenex to smell other foul-smelling chemicals insects produce to ward off predators.

• When the Intergovernmental Panel on Climate Change convened in 2007, attending scientists predicted that sea levels would rise between a half foot to 1.9 ft. by the year 2100. But there was much uncertainty, mainly because of a lack of information about the status of the polar icecaps. Since then, many more studies have been carried out on polar sea ice. Environmental experts at a conference in Copenhagen this March reported that both the Greenland and the Antarctic caps are melting at “an accelerating rate.” Based on present rates of melting, it is now predicted that sea levels will rise from 1.6 to 3.2 ft. by 2100. (The Economist, 3-14-09)

• Most of us can distinguish a spontaneous (genuine) smile, from a social (fake) one.

In fact, the two kinds of smiles are created by different brain circuits, and use different facial muscles. A social smile is a deliberate, conscious smile, usually of short duration. A spontaneous smile, however, is an automatic one that emerges from the subconscious “emotional” brain. The smile lingers, evokes a pleasant feeling, and involves many more facial muscles, especially the tiny ones around the eye socket that contract and convey the impression of “smiling eyes.” Both social smiles and spontaneous ones have their place in interpersonal communication. (Rita Carter, Mapping the Brain)