Thanks to Brilliant for supporting this episode of SciShow.

Go to Brilliant.org/SciShow to learn how you can take your STEM skills to the next level! [♪ INTRO]. There’s a lot going on in this world that we can sense using the five senses most people agree we have: hearing, touch, smell, taste, and sight.

But there’s also so much that we’re completely unaware of simply because it’s outside our range of detection. Some animals get information about the world using magnetic navigation, electroreception, and other senses that we don’t have at all. But there’s also animals that use the same senses we do, just better than we can.

And these super senses can not only help them find food and communicate, but they can even be life-saving for them. While we can experience these senses to a degree, we have our limits. So, what are we missing that other animals aren’t?

To an extent, you can hear when a rat squeaks. It’s really high-pitched and pretty much exactly what you would expect it to sound like. But you’re not hearing the whole story.

Just like humans can choose to talk in lower or higher pitches, rats can do the same. And even though their squeaks sound shrill to us, we are really only hearing their lower pitched sounds. Rat vocalizations can go even higher into ultrasonic ranges around 30-80kHz, which is higher pitched than our auditory range.

Humans can hear sounds ranging from about 20Hz to 20kHz. This means that rats can communicate with each other while we’re in the same room and we wouldn’t even know about it without the help of special microphones that can pick up those sounds. And there’s a lot of rat chatter.

Rats are social creatures, just like us, and they communicate regularly. And adults produce ultrasonic vocalizations during courtship. But they don’t just produce these ultrasonic vocalizations when communicating with other rats.

Scientists have discovered that rats are ticklish and they have ultrasonic giggles. Yes, researchers really went to work every day to put on a lab coat and do the important work of tickling a bunch of rats. They found that rats love to be tickled on the belly just like us, but not on the tail.

They’re situationally ticklish. So like us, if they’re in a scary place they’re not going to be in a ticklish mood and won’t produce ultrasonic laughter. Maybe in the end, they’re simply laughing at us feeble humans who can’t even hear it.

Rats are not the only animals that can communicate in a way that we can’t detect. A group of insects called tree-hoppers, and many other arthropods, can feel super small vibrations on leaves. Tree-hoppers like the umbonia crassicornis, or thorn bug, use these bioseismic cues for things like navigation, communication, finding food, and avoiding being food.

They have sensitive legs that can send and pick up these messages. And the unique shape of their exoskeleton makes them highly receptive to small vibrations. Thorn bugs can communicate with each other using these vibrations by producing a series of pulses on a leaf or twig; sometimes those pulses are just 30-40ms long.

Other thorn bugs are able to receive that message by sensing the vibrations through their legs and thorax. And researchers have learned that they can tell the difference between vibrations coming from in front of them and behind them. They think that if vibrations come from in front of the thorn bug at just the right frequency, the front of their thorax is affected the most.

And if they come from behind the bug, the back of the thorax is affected the most. They probably incorporate information from rotating their bodies and moving side to side to triangulate where the vibrations are coming from. Imagine being able to sense a buzzing in your chest and know that your friend is walking up behind you.

We use our ears that way to figure out if sounds are coming from the left or right, but our sense of touch isn’t nearly as attuned as the thorn bug’s. Aside from communication, some of these super animals use their powers to find their next meal. Many animals use their sense of smell to track down food.

And some super-smelling animals can detect odors under incredible circumstances, like underwater! Moles spend some of their lives on land, but can also swim underwater, similar to us. Unlike us, they use their nose way more than their eyes to figure out what’s going on in their environments.

So while we open our eyes underwater, moles smell underwater odors. These mammals can’t breathe underwater. But they can swim underwater and blow bubbles with their noses.

If they sniff them back in fast enough, they can trap scents in those air bubbles and detect smells without getting water up their nose. This sniffing motion is similar to what you might see from another speedy sniffer like a rat or mouse back on land, but by doing it in record speed, the mole is able to capture chemical information without inhaling water. They sniff about 0.06 to 0.1 milliliters of air at 6 milliliters per second.

This allows them to use their noses when foraging for underwater food by following scent trails left behind by prey. Humans, on the other hand, are totally oblivious to underwater smells. Most of us have pretty good sniffers...that is, if we sniff the air.

In fact, we can smell over one trillion odors. But because of the way we smell chemicals floating through the air, we are limited to experiencing the smells on land. And most mammals are that way.

Even mammals like dolphins that live underwater have a seriously decreased sense of smell compared to their fishy neighbors. So even when moles are in the dolphins’ turf, moles get more points for superior sniffing. When it comes to getting your next meal, your sense of taste is pretty important.

And some animals use this sense to find food for their babies and continue the species, and it’s not just limited to their tongue. Flies like the Hawaiian Drosophila can use pretty much their entire body to taste flavors around them. They have taste sensors on their head, body, legs, wings, and ovipositor, where they lay their eggs.

These flies first taste their food with the flavor sensors on their legs. And if it's sweet enough, they slurp it up through their proboscis, or mouth equivalent. They won’t even stick out their proboscis if their leg tasters haven’t pre-approved the meal.

But the flavor-detecting body part that might be most important for the continuation of their species is the ovipositor. When they’re preparing to find a place to lay eggs, the flies add another tasting to the menu. First, they taste the food with their legs, then their proboscis, and then their ovipositor to be extra sure.

The sensors on the ovipositor are specially tuned to taste sugar, so they’ll know if the location they lay their eggs is suitable to provide their babies with nutrients once they’re born. Flies can taste the same five flavors that we can: sweet, sour, savory, salty, and bitter. But we’re pretty limited to our mouths when it comes to flavor detection.

And I’ve never seen a human lick their nursery to make sure they’re ready to give birth. But it would make newborn child care easier for us if our babies could just feed themselves from their surroundings. Maybe flies are onto something.

Instead of licking the nursery, we’d be more likely to look around and make sure the baby has everything they need. But we’re still not super seers like this final animal. Reindeer live in the arctic surrounded by reflective snow, so they have evolved to utilize the sun’s ultraviolet light.

We humans can’t even see the UV rays that cause damage to our eyes and skin. But reindeer can because their eyes have adapted to not block out that part of the color spectrum. The reindeer eye has a cornea and lens like ours.

But theirs allow the UV spectrum at 322 and 385 nanometers of light to pass into their eyes. Their eyes are sensitive to the UV range of light because they have a pigment, known as the SWS1 pigment, that regulates how those wavelengths are seen. It’s been analyzed down to a gene called SWS1, which stands for “short-wavelength sensitive type 1.” The pigment can respond to wavelengths that are closer together, like ultraviolet rays, as opposed to wavelengths that are farther apart, like infrared rays.

But there’s still a lot we don’t know about how this gene and pigment allow them to see UV light. We do know, though, why it would be really useful for them. Seeing in UV allows them to see lichen, which they like’n to eat, and wolves, which like to eat reindeer.

Because while snow reflects UV light, lichen and wolves both absorb it! Wolves’ fur absorbs UV light, and the lichen have a rounded shape that scatters UV light. So these organisms stand out against the snowy backdrop.

So even when it comes to sight, we’re missing out on a ton of what’s going on around us. Humans can see wavelengths from about 400-700 nanometers. That’s enough to see red, orange, yellow, green, indigo, blue, violet, and intermediate colors between them.

But we can’t see UV light, and we’re definitely only seeing part of the picture. Maybe one day we will advance to the point of experiencing some of these things ourselves! I, for one, can’t wait to taste a pizza with my feet.

If you’d like to learn more about how we sense the world around us, you might want to check out today’s sponsor, Brilliant, which has courses about science, engineering, computer science and math. Like their course Waves and Light, which teaches about the nature of sound and light waves. And Brilliant has recently made their courses even more interactive, so you can really learn in a hands on way!

They also have Daily Challenges, which you can access for free, but if you sign up to become a Premium member, you’ll get access to the entire archive. You can sign up at Brilliant.org/SciShow and get 20% off the annual Premium subscription. Thank you for watching, and thank you again to Brilliant for sponsoring this episode of SciShow! [♪ OUTRO].