Southern right whales (Eubalaena australis), drawn to the Valdés Peninsula because of the shelter provided by its two gulfs, the Golfo San José and the Goldo Nuevo, often navigate with their tails upright in the water. When a tail stands immobile for tens of minutes, it is probable that the whale is completely vertical in the water in a kind of resting position; it has also been claimed that the whales use their tails as a sail, allowing the wind to do the work. After close observation, it is possible to predict when a whale will jump: a sudden and swift movement of the tail provides the burst of energy that enables the whale to project its massive body out of the water. Valdés Peninsula. Argentina. September and October 2004.