YouTube: https://youtube.com/watch?v=elIOKDaIVBc
Previous: The Common Houseplant That Hasn’t Flowered in Almost 60 Years
Next: Dire Wolves Were Real! But Not Wolves

Categories

Statistics

View count:177,433
Likes:6,992
Dislikes:1
Comments:300
Duration:10:47
Uploaded:2021-04-11
Last sync:2022-11-28 23:30
From the ability to see “invisible” types of light to the power to taste all over their body, meet five incredible animals whose super senses far surpass our own!

Hosted by: Michael Aranda

SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at http://www.scishowtangents.org
----------
Support SciShow by becoming a patron on Patreon: https://www.patreon.com/scishow
----------
Huge thanks go to the following Patreon supporters for helping us keep SciShow free for everyone forever:

Silas Emrys, Drew Hart, Jeffrey Mckishen, James Knight, Christoph Schwanke, Jacob, Matt Curls, Christopher R Boucher, Eric Jensen, Adam Brainard, Nazara Growing Violet, Ash, Laura Sanborn, Sam Lutfi, Piya Shedden, Katie Marie Magnone, Scott Satovsky Jr, charles george, Alex Hackman, Chris Peters, Kevin Bealer

----------
Looking for SciShow elsewhere on the internet?
Facebook: http://www.facebook.com/scishow
Twitter: http://www.twitter.com/scishow
Tumblr: http://scishow.tumblr.com
Instagram: http://instagram.com/thescishow
----------
Sources:
Correspondence with Dr. John T. Caprio
https://pubmed.ncbi.nlm.nih.gov/24395960/
https://pubmed.ncbi.nlm.nih.gov/24458639/
https://www.sciencealert.com/now-we-know-how-the-mantis-shrimp-s-tiny-brain-processes-such-amazing-vision
https://onlinelibrary.wiley.com/doi/abs/10.1002/cne.24788
https://www.sciencedaily.com/releases/2008/03/080320120732.htm
https://pubmed.ncbi.nlm.nih.gov/18356053/

https://www.nature.com/articles/nature03250
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4731273/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3172592/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3386870/
https://www.guinnessworldrecords.com/world-records/fastest-eater-(mammals)

https://pubmed.ncbi.nlm.nih.gov/23180048/
https://pubmed.ncbi.nlm.nih.gov/33119653/
https://pubmed.ncbi.nlm.nih.gov/32077991/

https://pubmed.ncbi.nlm.nih.gov/7685945/
https://pubmed.ncbi.nlm.nih.gov/28502972/
https://www.livescience.com/32970-what-animal-has-the-best-sense-of-taste.html
https://science.sciencemag.org/content/344/6188/1154.long

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5389353/
https://pubmed.ncbi.nlm.nih.gov/28432322/
https://www.nps.gov/yose/blogs/bear-series-part-one-a-bears-sense-of-smell.htm
https://mashable.com/article/bear-sense-of-smell/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3512284/pdf/joa0221-0609.pdf

Image sources:
https://bit.ly/32bJLGF
https://bit.ly/32c9S0a
https://bit.ly/3g5HJjp
https://bit.ly/3sbmj6R
https://bit.ly/3a91IKn
https://bit.ly/3a9gGA2
https://bit.ly/3gcQwjF
https://bit.ly/3mIg1KQ
https://bit.ly/2Q4lEHn
https://bit.ly/32egrPH
https://bit.ly/3a9297t
https://bit.ly/3mLE63m
https://bit.ly/329lJMB
https://bit.ly/3uMfydn
https://bit.ly/3tj4pk1
https://bit.ly/3ddmPgA
https://bit.ly/3dbJU3c
https://bit.ly/3x1JLYb
https://bit.ly/3x3u0jo
https://bit.ly/3mVnQ09
https://bit.ly/3gfGIoW
https://bit.ly/2QgLSWZ
https://bit.ly/3wTpuE4
https://bit.ly/3tkqO0n
https://bit.ly/2PS5DED
https://bit.ly/3mIgBIw
https://bit.ly/3x1K2dF
https://bit.ly/3ddjKgk
https://bit.ly/2PTPrTk
https://bit.ly/3dZ14A7
https://bit.ly/3soKcIx
https://bit.ly/2QqaJHK
https://bit.ly/3a4WX4s
https://bit.ly/3g8HVyv
https://bit.ly/3dfm8Dp
https://bit.ly/3mLERcI
https://bit.ly/3ti96uz
https://bit.ly/2ORrvzq
https://bit.ly/3a7CUm7
https://bit.ly/3e3UPLq
https://bit.ly/3g8SFwU
[♪ INTRO].

We owe a lot to our senses. Whether it’s hearing, sight, smell, taste,  or touch — whatever combination we have allows us to experience the  world in pretty exquisite detail.

But some animal senses are  so much more acute than ours that they’re basically superpowers. And we’re not just talking dog  whistles and eagle-eyed vision. From animals that can taste with their  whole bodies to those with incredible super-smell, the animal kingdom  gets a whole lot more extreme — and more fascinating.

Like in these five examples. For context, biologically speaking, a sensory system is a group of specialized  cells tuned to a certain type of signal. When they get the signal,  they fire off a nerve impulse, and that causes some kind of response.

For vision, those specialized  cells are called photoreceptors. Humans have four types of them, including  three that contribute to color vision, and each is tuned to a  different range of light waves. Our brains can decode the signals from these cells to discern millions of wavelengths,  which we then perceive as colors.

But our eyes are far from the best.  Other animals can see more colors, in lower light, or with more detail. And when it comes to cool eye tricks, the  mantis shrimp leaves everyone in the dust. This aquatic creature has the  most complex eyes of any animal.

Depending on the species, they can have between 16 and  21 types of photoreceptors! Most are tuned to narrow bands of wavelengths, from deep red to far ultraviolet—including  wavelengths that are invisible to us. But that doesn’t mean they can discern  more distinct colors than we can.

Researchers hypothesize that they  can probably recognize far fewer — possibly just one color per type of photoreceptor. But they can also process  color information really fast. See, for us, color vision hinges on  decoding that happens in the brain, and this takes a little time.

But in mantis shrimp, color  perception happens right in the eye. So, they can react to the situation more quickly. This speed is important for the mantis  shrimp’s dynamic, super-competitive lifestyle, which involves lots of flamboyant signaling,  fighting, and fast-action hunting.

But speedy color vision isn’t their only  trick. They can also see polarized light. Polarized light happens when light  waves all vibrate in the same plane — like, when they’re all oriented up and down.

This is in contrast to regular light, which is made of waves  vibrating in all orientations. To us, polarized light doesn’t really  look any different from regular light. But some animals, like mantis shrimp, can see it, and they use it to glean important information.

Not only that, but mantis  shrimp are the only animal known to be able to perceive circular polarized light. That’s polarized light that also spirals in  a clockwise or counterclockwise direction. They even have areas on parts of their bodies  that reflect this strange light pattern!

That may help them communicate  with each other or identify mates. And newer evidence suggests  that their complex visual system may also help them learn and remember  information about their surroundings. Next, in stark contrast to mantis shrimp,  the star-nosed mole is practically blind.

But vision isn’t very important for it anyhow, since it spends most of its time  in dark underground tunnels. Plus, it has a super-sense that more  than makes up for its poor eyesight. Maybe unsurprisingly, it has to do with its nose.

Which is so distinct, it gives  the star-nosed mole its name. But their star-shaped snout  isn’t so much for smelling. In fact, its pink, fleshy appendages  don’t have smell receptors at all.

Instead, they’re covered in mechanoreceptors. Mechanoreceptors respond to physical changes. So, when something stretches or pushes  on them, they fire off a nerve signal.

When there’s a bunch of them spread  across an area, like your fingertips, they can gather information about  features like shape, texture, and size. And overall, something like your  fingertip is pretty sensitive. But this mole’s centimeter-wide star  packs about five times more sensing power than you have in your entire hand.

In fact, it may be the most  sensitive touch organ in any mammal. And it gives the star-nosed mole unmatched  precision and speed. Like, officially.

The Guinness Book of World Records has  named it the world’s fastest eater, in the mammal category. These little animals are voracious predators, and they use their star to forage for  invertebrates on their damp tunnel walls. Their nose’s super sensitivity  lets it find the tiniest prey— ones that are too small for  other predators to bother with.

But on the flip side, because  their food is so small, they have to find a lot of it.  And here, too, the star delivers. As a mole forages, it touches its  star to up to 13 places per second. And it’s so good at collecting information  about things like size and texture, that it can decide within about 25 thousandths of  a second whether something is edible.   It’s also helpful that the  mole’s food-finding apparatus is optimally located right by its mouth,  and this likely adds to the speed.

In a simulated tunnel experiment, one mole found and consumed 8  pieces of food in just 1.8 seconds! Another animal that uses super-sensitive  touch to hunt is the harbor seal— but in a very different way. Seals are pinnipeds—a group that also includes walruses and eared seals, like sea lions.

And these animals are known for having  extraordinarily sensitive whiskers. The base of each whisker is  packed with mechanoreceptors. And compared to other mammals like your cat, pinnipeds have about ten times  more nerve endings per whisker.

That makes them sensitive  to the tiniest movements. And sort of how like people use their  fingertips, pinnipeds can pass their whiskers over an object to quickly and accurately  sense its size, shape, and texture. Walruses, for example, use their whisker  touch to find edible items on the seafloor.

But most true seals, like harbor  seals, take it up a notch. They can use their whiskers to sense  and follow trails of water disturbances that other animals or objects leave behind. Scientists think this helps them  hunt for their main food source: fish that swim in the water column.

And their unusual whisker shape makes  them uniquely well-suited to this task. Other animals, even other pinnipeds,  have smooth, cylindrical whiskers. But true seals have flattened,  wavy-looking or wiggly-looking whiskers.

A 2020 study showed that this  shape reduces drag in the water and reduces whisker vibrations as the seal swims. Since there’s little interference  from the seal’s own movements, it’s more sensitive to the  trails of other objects. And seals can extract impressive  details from these fleeting trails, including the size and shape of the object  that left it and the direction it was moving.

Even after the thing that made  it has moved tens of meters away. In other words, never play  Marco Polo with a harbor seal. Next up are catfish.

Catfish are bottom-dwellers that typically  live in dark, murky places. And although their eyesight is decent, their super-tasting  ability is what helps them find food. Compared to what we can do,  it’s also a little disturbing.

So, taste relies on chemoreceptors— sensors that are activated when they  bind to certain molecules, or chemicals. And while our taste receptors  live mostly in our mouths, some animals have them in weird places. Like, flies and butterflies  can taste with their feet, and octopuses taste with their tentacles.

But catfish can taste with their entire bodies. Basically, they can taste  anything that touches their skin, including water that’s recently passed  over something that they might want to eat. But instead of responding to  sweet, sour, or salty tastes, they’re highly sensitive to certain amino acids.

Amino acids are the building blocks of  proteins, so they’re found in all living things. But the key here is that these molecules  are released in high concentrations by catfish’s favorite food: aquatic invertebrates. Now, we can taste amino acids  too, but catfish can sense them at concentrations 100,000  to one million times lower.

And because their sense of taste is spread around, they can even tell what direction a  taste is coming from and hone in on it. The taste receptors are more concentrated  in certain places, though— like the fronts of their fins, which helps the catfish  pick up on taste trails as they swim. And they’re especially dense on the fleshy, whisker-like things around  their mouths, called barbels.

So, as catfish forage for  food, they brush their barbels along muddy stream beds—or, for  marine species, the ocean floor. And when the signal is strong  enough, the taste of amino acids can make them start snapping their  jaws at the surrounding water. But that’s not the only unusual sensing  ability that sets catfish apart.

In a 2014 study, researchers  found that at least one species can sense tiny decreases in water pH, or acidity. It’s not yet clear if this is  a function of their taste buds, but it fires up the same nerves. Either way, pH-sensing appears to  help them find tasty, little worms— since when the worms exhale carbon dioxide, it combines with the water  nearby to make carbonic acid.

Our final animal is bears,  known for their super-smell. Smell uses chemoreceptors, kind of like taste. But these receptors bond to molecules  that move through the air, specifically.

Now, considering that dogs can sniff out  things like drugs, money, and even cancer, it’s not surprising that  humans aren’t going to win any awards in the smell department. But bears are especially impressive. Like other animals with keen noses, they just have more real estate  dedicated to sensing smell.

In fact, compared to us, some bear  species have five times more brain space dedicated to smell, and about 100  times more area inside their noses. Their sense of smell is not only keen  but also remarkable for its range— a distance that’s measured in kilometers. In fact, the range is so great  that it’s really hard to measure exactly how far it extends.

Long-distance smell is useful because  most bear species roam over large areas, and it keeps them up-to-date  about what’s going on around them. Like, it can help them track their kids,  sense potential mates, and sniff out food. And lots of bear species seem to have this gift— as a fair number of backpackers will tell you.

Like, in Yosemite National Park, black  bears can sniff out food hidden in a car— even crumbs and food residues. And  then rip the car apart to get it. And polar bears?

They can  pick up scents on the wind and track them to seal breathing  holes up to three kilometers away. Bears’ keen noses may also help  them communicate with each other through scents left behind in their footprints. Like, male brown bears have a certain way  of grinding their feet into the soil when they really want to leave their scent behind  and let females know they’re available.

And pandas can smell 120-day-old  scents left behind by other bears. Which is just, well, humbling. So, we humans like to think we’re the best because of our big brains and  ingenuity—and those are pretty great!

But it’s also worth sitting back  and just admiring how other animals get to experience the world, too. Because there’s a lot to smell, taste,  hear, and see out there, and sometimes, the only way we can learn about it is by  watching the rest of the animal kingdom. This episode of SciShow goes  out to our patrons on Patreon!

You might not have a star-shaped  snout or be able to taste things with your entire bodies, but we  still think you’re pretty incredible. Thanks for supporting free  science education on the internet— we couldn’t do this without you. If you’re not a patron, thank you for  supporting us by watching the show!

If you want to learn more about our Patreon, you can also go to Patreon.com/SciShow. [♪ OUTRO].