Sunday, December 19, 2021

Some Mammals have infrared antenna-like structures to detect predators

Amazing stuff!

"... The new research, published last week (December 8) ... builds on a body of unpublished evidence collected not by a biologist, but by a physicist, Ian Baker, who develops infrared sensors for a British defense company.
Baker has long brought his work home with him ... using infrared cameras containing his sensors to scan the fields and woods near his house in Southampton, England, for animals. A series of anecdotal observations—such as the fact that cats seem to “stack” their bodies behind their cold nose when hunting, along with a similar twisting behavior in swooping owls—led Baker to hypothesize that perhaps these predators “have to conceal their infrared to be able to catch a mouse,” in effect “hiding their heat.” ..."

From the abstract:
"Many small animals, including shrews, most rodents and some marsupials, have fur composed of at least four types of hair, all with distinctive and complex anatomy. A ubiquitous and unexplained feature is periodic, internal banding with spacing in the 6–12 µm range that hints at an underlying infrared function. One bristle-like form, called guard hair, has the correct shape and internal periodic patterns to function as an infrared antenna. Optical analysis of guard hair from a wide range of species shows precise tuning to the optimum wavelength for thermal imaging. For heavily predated, nocturnal animals the ability to sense local infrared sources has a clear survival advantage. The tuned antennae, spectral filters and waveguides present in guard hair, all operating at a scale similar to the infrared wavelength, could be a rich source of bio-inspiration in the field of photonics. The tools developed in this work may enable us to understand the other hair types and their evolution. ..."

Some Mammals May Use Specialized Hairs to Detect Predators' Heat | The Scientist Magazine® When observed under a microscope, guard hairs from mice resemble optical sensors used in thermal cameras to detect heat, according to a new study.

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