African sandgrouse inspires a new design for more efficient water bottle

Sandgrouses nest about 20 miles from watering holes and gather water in their feathers to bring to their thirsty chicks. They can hold about 15 percent of his body weight in water, and keep most of it safe during a roughly 40 mph flight home that takes about a half hour.

Their specially adapted belly feathers are the key.

Both dry and wet

Mueller and MIT engineer Lorna J. Gibson zeroed in on the microstructure of the belly feathers using scanning electron microscopy, microcomputed tomography, light microscopy and 3D videography, observing them both dry and wet. 

Mueller described the individual feather structure as "magnificent,” noting that individual feathers held the water through a forest of barbules near the shaft, working together with the curled barbules near the tip, acting almost like caps.

"That's what excited us, to see that level of detail," Mueller said. "This is what we need to understand in order to use those principles to create new materials."

Mueller and Gibson hope to now use their findings to underpin future engineering designs.

They imagine a water bottle or sports backpack that safely holds a lot of liquid but includes an inner feather-like system that keeps the water from swinging around while someone moves with it. 

They have also conceived of next-level medical swabs that are easier to use, "where you can efficiently soak up liquid, but it's much easier to release it," they said in their statement.

The study has been published in the Journal of the Royal Society Interface.

Study abstract:

Desert sandgrouse, such as the Namaqua sandgrouse, nest up to 30 km away from watering holes. Adult male desert sandgrouse have specially adapted feathers on their bellies that hold water, even during flight, allowing the birds to transport water back to the chicks at the nest. The structure of the belly feathers and aspects of the mechanism by which they hold water was first described by Cade and Maclean. Here, we use scanning electron microscopy and micro-computed tomography as well as videography to characterize the geometry of different components of the belly feathers and to show how differences in their bending stiffnesses contribute to the water-holding mechanism. The results of this study will be used in a companion paper to model computationally water uptake by the feather.