Unless you’re like Haley Joel Osment’s character in The Sixth Sense, most humans are born with just the five basic senses: vision, hearing, touch, taste, and smell. The same goes for other animals, though you may be surprised to learn about all the “sixth” senses that exist in the animal kingdom. 

Some creatures can sense electrostatic fields, others can visualize heat, and various animals use sound waves to navigate their surroundings. Here are several examples of animals with senses that we humans lack.

Sea Turtles: Magnetoreception

Imagine having the ability to navigate long distances without having to consult Google Maps even once. Sea turtles have just that, specifically in the form of magnetoreception, which essentially acts as a built-in compass that gleans information from the planet’s natural magnetic field. Turtles can also sense waves emanating from human-made structures such as offshore wind farms and power lines.

Whatever the source may be, studies show the turtles essentially create maps in their brains using the information provided by Earth’s magnetic fields. They can use those “maps” to travel to specific destinations, even ones located thousands of miles away. This comes in handy especially during migratory periods, allowing them to return to the precise spot they originally migrated from. 

Magnetoreception is also present in a number of migratory animals besides turtles, such as salmon, birds, and insects. Perhaps one day scientists will devise a way for human snowbirds to use magnetoreception when traveling to Florida for the winter, but that day has not yet arrived.

Jewel Beetles: Infrared Detection

Much like expectant parents searching for the right hospital, the jewel beetle is rather particular when it comes to where it gives birth. But unlike human parents, this beetle prefers to do so inside the charred husks of trees that have been damaged by forest fires.

You may wonder how jewel beetles can track down forest fires without access to news or social media. The answer lies in the creature’s genetic ability to detect infrared radiation from up to 50 miles away: Jewel beetles possess a pair of infrared-detecting organs that are used to sense heat. 

Those organs are located under their wings and absorb radiation at the precise dominant wavelength (3 micrometers) emitted by wildfires. After absorbing the heat radiation, the organs expand, providing the beetle with a sense of which direction it must go to find the charred arboreal remains.

Octopuses: Polarized Vision

If you’ve ever worn a pair of polarized sunglasses, you know they’re ideal for eliminating intense glare. But under the sea, octopuses, along with other cephalopods including cuttlefish, also rely on polarized vision. Obviously those creatures don’t have access to Sunglass Hut or Warby Parker, but thankfully that helpful trait is built into their genetic makeup.

Octopuses are colorblind, and rely on polarized vision for protection and to navigate their surroundings. In many other creatures, the ability to process polarized light is impacted by spatial distortion — e.g., how the density of water causes light to refract and bend in a way that causes objects to appear blurry, closer/farther, or shaped differently than their actual form. 

But an octopus’s photoreceptor cells are able to process the polarized light directly without distortion. This allows octopuses to clearly see the polarized light that reflects off predators and prey, and to camouflage their bodies to match the polarization of their environment. 

There’s also a theory that octopuses may rely on this ability for hidden communication. In other words, they could potentially reflect polarized light off their own bodies to communicate with other octopuses, knowing that the reflections are imperceptible to other sea creatures.

Bats: Echolocation

It’s a common misconception that bats are blind; if anything, they probably have better vision than most humans taking eye tests at the DMV. But despite the ability to see, bats largely rely on what’s known as echolocation to navigate and communicate.

Echolocation works by bats producing high-pitched sound waves that are imperceptible to the human ear. Those waves bounce off the surrounding environment and return to the source — the bat itself — to provide it with essential information. 

For instance, besides communication and navigation, bats also use echolocation for hunting, producing sound waves that bounce off an insect to reveal its location. This tells the bat where it needs to swoop for a nice five-star dinner.

Elephants: Seismic Communication

Elephants seem to enjoy music, and if we had to guess their favorite tune, it may be “Good Vibrations” by the Beach Boys. While human beings are able to feel vibrations in their immediate vicinity, elephants are notably skilled at detecting seismic activity. 

Elephants are able to detect those low-frequency rumbles in one of two ways: One theory is that it happens through bone conduction, specifically the huge bones located in their equally massive ears. Other researchers believe elephants have highly attuned mechanoreceptors located in their toes, feet, and trunks, which are sensitive to even the slightest vibrations.

There’s evidence of elephants sensing vibrations from thunderstorms as far as 100 miles away. Elephants in Angola were spotted heading north toward storms in search of water. Elephants themselves can also generate vibrations for communication that can travel as far as 20 miles, alerting other elephants within that range to their presence.

It’s said that laughter is the best medicine, but it’s also one of the most multifaceted reactions. Humans use laughter to bond with other humans, and to express joy. Laughter has even been shown to soothe the nerves and have a psychological effect on stressful or awkward situations. But while laughing is commonly considered a purely human response, several members of the animal kingdom can be heard cackling through the day and night for a number of reasons.

Apes

It comes as no surprise that our closest wild animal relatives engage in laughter, just like we do. Primate laughter sounds quite different from human laughter, however, resembling more of a breathy pant as apes can laugh on both the inhale and exhale. Adult humans can only laugh on exhales, but interestingly enough, human babies can laugh during both, just like apes.

Apes generally use laughter to show they mean no harm during playtime, which can get quite rough, and signal their harmless intent by dropping their lower jaw to reveal an open mouth. Teeth baring can be a sign of aggression for apes, which is why the relaxed jaw posture is so important. 

Dogs

Heads thrown back, upturned mouths, squinted eyes, and a harmless flash of teeth. This is what it looks like when dogs laugh, but is it truly a sign of joy or just an anthropomorphic trait we’ve assigned them? It could certainly be a little of both, but one study showed that dogs do vocalize in a specific way that evokes play and relaxation in other canines around them.

The trick here is to look beyond the wide smile and listen to the sound. To our ears, the noise associated with laughter in dogs just sounds like regular old panting, but for dogs, this breathy expression is filled with a range of frequencies that suggest playtime is on the table.

To test this, researchers gathered 30 puppies into two equal groups for what might be the best day of work ever. Fifteen of the puppies were played a recording of dog “laughter,” and 15 were not. The group that heard the pants immediately started playing, while the other group did not.

What’s even more interesting is that the playful group didn’t respond to other canine sounds that were recorded to capture the panting play sounds, like barking and whining, suggesting that this pant/laugh alone was enough to get the games going. 

Rodents

It’s too high-pitched for a human to pick up, but rats do laugh, and for many of the same reasons we do. In one study, rats were fitted with electrodes that measured their response each time the rodents were tickled. The rats and researchers played games of hide and seek, and when the rats found the humans, they were rewarded with a flick of the fingers on their backs and bellies.

How do the scientists know that the rats were laughing? Not only did the electrodes catch the high-pitched squeals of joy during these tiny tickle fights, but they also measured the PAG, or periacqueductal grey. This is a midbrain structure that regulates pain by releasing endorphins and enkephalins that are also released when you chuckle. It also organizes fight or flight responses, aids in vocalization, and works to organize involuntary laughter.

Researchers noticed that neurons in the PAG were lit up when the rats were screeching with joy, but when they injected the area with chemicals to essentially turn it off, the rats stopped laughing when they were touched. 

Birds

Not all birds laugh, but a few avian species are known for their humorous calls. Parrots, both wild and domesticated, have been known to laugh as a way of inciting play and expressing joy. Kea parrots in New Zealand are famous for their cackles and sustained calls. They make this sound when they’re alone and when they’re with others, and research has shown that when they laugh in the company of other Keas, playtime ensues.

Pet parrots such as African greys and cockatoos also laugh, but only because they are experts at mimicry. If you’re laughing around the house and they hear you, they’ll join in on the fun, but not necessarily because they find you funny.

Perhaps best known for their distinct laugh are Kookaburras but they, too, aren’t doing it because they’re amused. These sounds are used to defend territories, or call out to and locate other kookaburras included in their riot, or group. 

Spotted Hyenas

One of the most famous laughing animals in the wild, hyenas are known for their cackling noises, but what you hear isn’t as funny as it sounds. That high-pitched, repetitive chuckle that spotted hyenas are associated with isn’t actually a sign that these scavengers are having a good time. In fact, it most often means the opposite.

Highly social animals that they are, and living within a very specific pecking order, hyenas use this sound to communicate with other members of their clan. They can use “laughter” to introduce themselves, and their status, to other members, with younger hyenas calling out in higher pitches, and older, more established ones speaking in lower tones. The wild, unsettling giggle that you hear is usually a sign of stress, either warning other hyenas to back off, or to alert other clan members that food, or danger, is nearby. 

Dolphins

Dolphins laugh for reasons that are very close to human displays of joy. Expressed as a high-pitched staccato, sometimes followed by a whistle, dolphins mostly use the sound of their laughter to assure other dolphins that they mean no harm. This is done as a way to keep the peace during play fighting, which could easily get rough and mistaken for actual fighting.

This sound has not been recorded during aggressive activities, like biting, leading scientists to safely assume that this form of laughter is, indeed, used to express happiness. Like many of the animals on this list, dolphins are social animals who live in pods where communication is key, and these sea dwellers use a series of clicks, whistles, and chatters to express themselves to those around them.

Humans can grow wise, grow long in the tooth, and even have their hearts grow fonder. But the one thing that humans can’t grow is a brand new appendage, and the sheer idea of limb regeneration sounds like something straight out of a sci-fi novel. But for certain animals, the ability to restore missing body parts is built into their genetic fabric. It may seem like an act of magic, but in reality, it’s biology working as intended. Let’s look at five animals that can regenerate with ease.

Salamanders

Salamanders are slimy, slender, and the only vertebrates able to regenerate entire limbs. In the event an appendage is severed — possibly due to a hungry avian predator taking a quick bite — the wounded area will first be sealed off with a protective skin barrier called the epithelium. Next comes the formation of a blastema, a mass of proliferative cells that are genetically coded to stimulate regrowth of the lost body part. Over several weeks, the lost limb will grow back to its precise size and orientation, though exactly how continues to be studied. Furthermore, any scarring or other evidence of the injury completely disappears.

Of the hundreds of different salamander species distributed worldwide, not all have the same regenerative capabilities. But two that are particularly adept and have been widely studied are the Eastern Newt and Mexican Axolotl. You might be familiar with the axolotl because of its cute appearance and natural smile — you’d probably smile too if you had such a unique ability. Not only can axolotls regrow their limbs, but also damaged organs such as the lungs, ovaries, brain, and spine.

Starfish

We’re taught as children to believe that starfish have five arms. But much like Santa, it’s best not to believe everything you hear as a kid. While there are tons of sea stars with five arms, some have more than 50. Furthermore, they’re able to regrow those appendages as needed, so long as the central part of the body remains intact.

When a starfish’s arm is severed, partially damaged, or intentionally detached to escape prey, the arm will regenerate in time. The process can be slow, as it takes up to a year to grow back lost limbs. But over that time, stem cells will be directed from the center of its body toward the injured area, stimulating growth of the lost body part(s).

Deer

Deer can’t regrow lost fleshy tissue. However, they can regenerate one extremely complex mammalian structure that contains dermis, blood vessels, nerves, cartilage, and bones: deer antlers.

Deer antlers are the only known mammalian organ (yes, antlers are an organ) that can fully grow back after being lost. The regrowth is possible thanks to stem cells emanating from the neural crest in a deer’s pedicle periosteum — a membrane located around its skull. After a deer sheds its antlers (which tends to happen yearly) they’ll slowly grow back over the next few weeks. Antlers regenerate at one of the fastest rates of any animalian body part, as they grow by roughly ¼-inch each day until fully formed — or the same rate as a teenager going through a growth spurt.

Zebrafish

Zebrafish are a tropical, freshwater minnow that’s found naturally throughout India, as well as in many pet shops around the world. Despite their minute stature, they have one of the most complex regenerative systems in the animal kingdom. Zebrafish can regrow amputated fins, and have the ability to repair lesions around the brain, retina, pancreas, spine, heart, and other living tissue. They’re as versatile as a Swiss Army Knife — though perhaps it’s more apt to call them a “South Asian Army Knife.”

When you look at a zebrafish’s heart tissue, for instance, roughly 12% to 15% of the cells are stem cells that originate from neural crest cells. Humans actually have similar cells, but they lose their regenerative function during development. Zebrafish retain their ability to repair heart muscle into adulthood, which is why scientists have studied these fish to see if they can apply those genetic lessons to repairing human heart tissue. While there’s still research to be done, this means we may be a step closer to mending that broken heart from a recent breakup.

Sharks

Sharks can’t regrow fins, tails, or other fleshy body parts, which is ideal considering how powerful and terrifying Jaws already was. But sharks can regenerate one particular body part, and it happens to be one they’re arguably best known for: their teeth. While precise numbers vary, sharks have 50 to 300 teeth arranged in up to 10 rows. But those teeth do get lost, and estimates say certain species shed as many 30,000 teeth in a lifetime.

Now it’s a good thing shark dentists don’t exist, as they’d likely go out of business with how little work they’d need to do. That’s because sharks don’t need implants or crowns to replace those tens of thousands of teeth — they simply regrow them.

Whether it’s a single tooth or an entire row, there’s always another tooth or plate of teeth ready to shift around and replace it; picture a conveyer belt, where a new set of teeth moves into place. This is made possible due to stem cells that work to constantly replenish teeth, making it possible for sharks to have unlimited teeth depending on their needs and lifespan.