Maneuvers of bats exposed

2007/06/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Zoologia

Birds and bats do not fly the same way. For example, the upward movement they make when waving wings is different; birds use feathers to have no air resistance, and bats, having no feather, have to place wings in vertical position in the upward movement. It is not a very aerodynamic solution, but it has the advantage of manoeuvring easily at low speed. Some physicists at Lund University in Sweden have discovered why.

The secret lies in the swirls that cause the wings. The whirlwind that generates each bat wing when moving upwards hardly affects the other. Somehow, the wings work alone, which makes the ability to manoeuvre very high. The birds, however, fly coordinated by both wings, which from the aerodynamic point of view create a very effective pattern of swirls, but they cannot maneuver so easily.

To detect turbulence, Lund University physicists have used a wind tunnel and fog. In the wind tunnel a small fountain has been installed that pours honey and bats have been measured while eating honey. Experts say that the way of flying from bats is similar to that of bees, but, of course, it is not for the issue of honey; all bats fly that way.