Basking sharks found to choose mates by swimming in giant circles
Even though the plankton-eating basking shark is the world's second-largest fish, much of its life has eluded observation. Now, however, researchers have determined that the usually solitary animals find mates by meeting up and circling around one another, forming underwater shark-rings.Over the past 40 years, such circling behaviour has occasionally been observed off the North Atlantic coast of Canada and the US. The three-dimensional donut-like shape formed by the sharks' swimming pattern is known as a torus.Previously,…