Madrid, 12 (Europe Press)
These feathers absorb and retain water so efficiently that male Namaqua sandgrouse birds can fly over 20 km from a distant watering hole to the nest and still retain enough water in their feathers for the chicks to drink and survive. In the scorching deserts of Namibia, Botswana and South Africa.
How do these pens work? While the scientists extrapolated a rough picture, they took state-of-the-art microscopy tools and patient work with a set of feathers of bugs to unlock the unique structural details that allow the feathers to retain water.
The findings appeared in the journal Interface of the Royal Society, in a paper written by Lorna Gibson, professor of materials science and engineering and mechanical engineering at MIT, and Professor Jochen Müller of Johns Hopkins University.
Gibson and Mueller conducted their studies using electron microscopy, microcomputed tomography, and video imaging. They borrowed the belly feathers of the Namaqua sandgrouse from Harvard University’s Museum of Comparative Zoology, which contains a collection of specimens from about 80 percent of the world’s birds, MIT reports.
Bird feathers generally have a central shaft, from which smaller quills extend, and then smaller barbells. However, sandpipers have a different structure. On the inside of the feathers, the barbells have a spirally coiled structure near their base and then a straight extension. In the outer region of the feathers, the barbells lack a spiral spiral and are simply straight. Both segments lack the grooves and hooks that hold the feathers of the circumferential feathers together in most other birds.
When wet, the coiled portions of the barbules separate and coil to lie perpendicular to the feather, producing a dense thicket of fibers that can retain water through capillary action. At the same time, the barbells on the outer region curl inward, which helps to retain water.
The microscopy techniques used in the new study made it possible to measure the dimensions of the different parts of the feathers. In the inner region the shafts of the quills are large and rigid enough to provide a rigid base on which to deform the other parts of the feathers, and the barbells are small and flexible enough that the surface tension is sufficient to support them. The straight extensions are in the shape of a teardrop. Structures that retain water. In the outer region, the axons of the spines and barbs are smaller, which allows them to wrap around the inner region, and to retain water more.
While previous work suggested that surface tension produced water-holding properties, “what we did was take measurements of the dimensions and do some calculations to show that this is really what’s going on,” says Gibson. His group’s work has shown that the different stiffness of different parts of the feather plays a major role in their ability to hold water.