Mammals With Inspiring Snouts
Mammal species with remarkable noses
give scientists both education and inspiration.
As funny as they look, the following mammal noses are well designed – so much so, scientists are looking to them for engineering ideas.
Elephant’s trunk may be one of most sensitive body parts of any animal (New Scientist). 400,000. That’s the number of nerve cells in the trunk of an elephant. It seems like overkill, but it gives this iconic large mammal an incredible sense of touch, and great flexibility. A trunk is gentle enough to pick up a peanut from a child’s hand, yet strong enough to lift a log. Reporter Jason Arunn Murugesu says, “The bundle of nerves that controls the elephant’s trunk contains 400,000 neurons – a lot more than we expected – suggesting the trunk is incredibly sensitive.” Neurons related to touch in the trunk are triple what are in the optic nerve, which usually has the densest packing of nerve cells. German scientists found this out by dissecting eight heads of Asian and African elephants that were sick or had died in zoos. The head with trunk and all weighs 650 kg (143 lb), so it was not an easy task.
Oh elephant, what big nerves you have! (Nature). A photo of two elephants caressing their trunks begins this article. “The outsize nerve network running from an elephant’s trunk to its brain hints at a highly developed sense of touch.” The nerve bundle for an elephant’s trunk weighs “a whopping 1.5 kilograms” (3.3 pounds).
The researchers found that the elephants’ sensory-nerve fibres can be more than 2 metres long, and that the nerve that carries tactile signals from the trunk to the brain is more than three times as thick as the nerve responsible for relaying visual information. The elephant’s trigeminal ganglia, the bundle of nerve-cell bodies that sits just below the brain, is one of the largest structures used for carrying sensory information known in any animal.
Humans cannot imagine the tactile experiences of the elephant with such an “extraordinary sense of touch.”
Earlier reports on CEH discussed robot designers trying to imitate the flexibility and strength of the elephant trunk (e.g., 9 July 2007). Neither article attempted to explain how such a complex proboscis might have evolved.
The Pig and the Dog
Snorkeling Gear, Animal Noses Inspire Better Personal Protective Equipment (American Physical Society, 22 Nov 2020). Back when personal protective equipment (PPE) was hard to come by in fall of 2020, Cornell physicist Sunghwan Jung at Cornell University, got together with colleagues from other institutions to design masks that “take their shape from the nasal cavities of animals.” Pigs and dogs have such great senses of smell because of fluid dynamics inside their snouts.
Animals like dogs, opossums, and pigs are renowned for their super-sensitive sniffers, said Jung. “They have a very complicated nasal structure, and we tried to mimic that structure in our filters.”
The human nose is fairly straightforward and vacuous, said Jung. But dogs and pigs are different. They have twisty, tortuous nasal cavities, and that’s partly why they have such strong senses of smell. “Fluid mechanics tells us that if you have such a tortuous air pathway, you have more changes to capture more particles,” said Jung.
Camels’ noses inspire a new humidity sensor (American Chemical Society). In a press release January 19, ACS said, “A Camel Nose-Inspired Highly Durable Neuromorphic Humidity Sensor with Water Source Locating Capability.” Why did camels inspire such a thing? For one, camels can get by with very little water while traveling long distances. For another, camels are very good at sensing the presence of water. Chinese researchers, therefore, took a closer look at the interior of a camel’s nose and tried to imitate the structure inside.
Narrow, scroll-like passages within a camel’s nose create a large surface area, which is lined with water-absorbing mucus. To mimic the high-surface-area structure within the nose, the team created a porous polymer network. On it, they placed moisture-attracting molecules called zwitterions to simulate the property of mucus to change capacitance as humidity varies.
Their device performed well at sensing low levels of moisture in the air. It could even sense moisture emanating from a person’s body. Such devices could “become the basis for a touchless interface through which someone could communicate with a computer,” the inventors think. Some day you may thank a camel for operating a touchless screen with waves of your hand.
We reported over a year ago another inspiration from camels: their immune systems. Nanobodies from camelids like llamas provide hope for Covid-19 treatments (11 Aug 2020). What happened to that story? It’s still making appearances in the news. Teams from half a dozen universities are still working on the idea. Here are some links in 2021 for more information.
Nature, June 2021
Nanobodies from camelid mice and llamas neutralize SARS-CoV-2 variants
NIH: Llama antibody engineered to block coronavirus
BBC: Covid: Immune therapy from llamas shows promise
U Pittsburgh: Llama Nanobodies Could be a Powerful Weapon Against COVID-19