All animals are bilateral, meaning they have an even number of limbs - two arms, two legs. But some have evolved clever workarounds to this biological code: Kangaroos, for example, use their tails as a fifth limb to help launch them forward.
Now, scientists are intrigued by another species that has evolved to think outside the bilateral box: Lovebirds. These small, brightly coloured parrots use their beaks as a third limb to help them climb trees, according to new research.
Scientists watched Lovebirds using their beaks while climbing, but weren’t certain that the beak was actually moving them forward, or if it served more as a stabilizing hook to help them stay balanced.
To more fully understand the birds’ unique gait, researchers brought six rosy-faced lovebirds into the lab, then used high-speed cameras and sensors to track their movements at various incline angles. After analyzing the data, they found that lovebirds began using their beaks as a third limb periodically once the pitch grew steeper than 45 degrees. On completely vertical surfaces at a 90-degree angle, they used their beaks in this way 100 percent of the time while climbing.
They also found that the birds’ beaks provided nearly as much power as their legs in their cyclical tripedal gait. When adjusted for weight, the beaks’ power was equal to or greater than the power of a rock climber’s arms or other climbing primates’ forelimbs.
“For them to take their faces and integrate it into their stride cycle is pretty incredible,” says Melody Young, an anatomist at the New York Institute of Technology and the study’s co-author.
It’s not clear exactly why parrots evolved this way, but researchers suspect it’s because they alternate their legs when they walk and, thus, cannot hop up and down tree trunks.
Today's OGN Sunday Magazine articles