Underwater surfaces can develop into dirty because dirt, algae and bacteria accumulate on them scientists call “pollution”.” But furry mammals like beavers and otters, which spend most of their lives wet, manage to avoid slimy fur. These antifouling properties are due partially to one among fur’s unique properties – the undeniable fact that each hair can flex and bend because the animal moves.
I’m a mechanical engineer which studies fluid dynamics or the behavior of fluids. My team currently published a study showing that fur moving back and forth in a stream of dirty water gathered lower than half the quantity of dirt compared to fur held rigidly at each ends.
While many animals have fur that appears to be self-cleaning, semi-aquatic mammals have essentially the most dirt-resistant or “antifouling” fur.
In our recent study, we compared the fur fibers of beavers, otters, springboks, coyotes and other species using a stream of water containing titanium dioxide, a standard cosmetic additive. Titanium dioxide easily attaches to surfaces equivalent to skin. Our team pumped dirty water through individual fibers in a closed loop for twenty-four hours, then cleaned the fibers to measure the quantity of titanium dioxide gathered in them.
My colleagues and I then used mathematical techniques to mix the entire fur’s properties right into a single number that predicted its antifouling behavior. We considered each strand of fur’s ability to bend, fluid flow through it, and other unique characteristics of every species.
We found that the power to bend was crucial to keeping the animal’s coat clean.
Why is that this essential?
Pollution can damage the affected surface. When fur becomes dirty, the pattern of individual strands on the animal’s skin is disrupted, and the animal can have difficulty staying warm or dry.
Industrial deterrent methods often used to protect the bottoms of ships and the insides of pipes use harmful chemicals and eat energy and materials, unlike naturally created solutions.
Discovering how fur naturally stays clean could lead on to more environmentally friendly solutions to stopping pollution in water supplies, the marine environment and even medicine. Solutions may include surfaces with parts that may bend and move, or people who have small hairs on the surface.
Fur research can be revealing more about how these mammals evolve to survive in numerous environments.
What continues to be unknown
Animal fur and the means of regrowth each are complexsubsequently, we still don’t fully understand how all of the intricate properties of fur, from texture and length to cross-sectional shape and environmental conditions, affect cleanliness.
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Hair strands in fur don’t all the time move individually. In animals, the hairs are tightly packed and probably groom each other by rubbing because the host moves. We cannot yet say whether rubbing and moving affects the cleanliness of the host animal.
What’s next
My colleagues and I actually have just delved into the key of cleanliness in furry mammals, and there may be way more we are able to test. Future work could expose fur to biological contaminants equivalent to bacteria and algae, or have a look at the role fur plays in cleanliness.
The only mammal known to actually develop into polluted is the sloth – algae grows on their fur.
