Under the Sea

The ocean covers most of the planet. So do these questions.

801. Is the ocean salty because of fish tears?

No. Rivers carry salt from rocks into the sea. The fish are fine, emotionally. Rain slowly wears away rocks on land, picking up tiny bits of minerals, including salt, and rivers carry them to the ocean. When seawater evaporates, the salt stays behind, so over millions of years the ocean has become saltier and saltier. Undersea volcanoes and vents add more. If all the salt in the oceans were spread over the land, it would form a layer over 150 metres thick, about as tall as a 40-storey building. That's a lot of salt. It's also why your fries taste like the beach. Just kidding. Mostly.

802. Do whales get seasick?

No. They are the sea. It would be like you getting human-sick. Seasickness happens when your eyes and your inner ear disagree about how you're moving (see question 502). Whales live their whole lives in moving water, so their bodies are perfectly used to the rocking. They glide through storms, ride huge waves and sleep while floating, all without a single queasy moment. Whales are so comfortable at sea that some sleep vertically, hanging in the water like giant, peaceful sausages. Meanwhile, humans on a whale-watching boat are leaning over the railing, looking green. The whales are watching them. The whales find it hilarious.

803. Can an octopus give a hug?

Eight arms means four hugs at once. Very efficient. A little sticky. Each octopus arm has hundreds of suckers that can taste and feel what they touch, so an octopus hug is also an octopus taste test. Octopuses are extremely smart: they can open jars, solve puzzles and escape from aquariums, sometimes sneaking out at night to raid other tanks for snacks and then sneaking back before morning. One famous octopus in New Zealand escaped through a drain pipe into the ocean. If an octopus hugs you, it's also checking your pockets. Hold on to your wallet. And your sandwich.

804. Why is it called a starfish if it's not a fish?

Some scientists prefer "sea star" for exactly that reason. The starfish has not commented. Sea stars have no brain, no blood (they use seawater instead) and eat by pushing their stomach out of their body and onto their food, digesting it outside, then pulling their stomach back in. That's horrifying and amazing. They can also regrow lost arms, and some can grow a whole new body from a single arm. Jellyfish aren't fish either (see question 809), and neither are cuttlefish or crayfish. The ocean is full of things named "fish" that aren't fish. It's a naming disaster down there.

805. Do crabs walk sideways because they're shy?

It's how their legs bend. Also, see question 18. They have reasons to avoid us. A crab's legs are jointed so that sideways is the fastest and easiest direction, a bit like how you'd scuttle along a narrow ledge. Some crabs can walk forward, slowly, but they look uncomfortable doing it. The crab in this book walks sideways with great dignity, like a tiny butler leaving a room. It has been watching the events of this book from the edge of the page, quietly judging. It has also stolen several fries from the seagulls (see question 837). Nobody suspects the crab. That's its secret.

806. Is a seahorse a horse?

It's a fish. It cannot be ridden. People have tried. Seahorses are small, slow and very bad swimmers; they mostly anchor themselves to seaweed with their curly tails and wait for food to drift by. They're one of the only animals where the male gets pregnant: the female puts her eggs in the male's pouch, and he carries them until hundreds of tiny seahorses pop out. Seahorse couples also do a little dance every morning to greet each other. That's adorable. They have horse-shaped heads, monkey-like tails and kangaroo-like pouches. They're three animals wearing one fish costume.

807. Where does the ocean end?

At the beach, mostly. Then it comes back with the tide. Technically, all the world's oceans are connected into one big ocean, with different names in different places, like neighbourhoods in one city. The Pacific is the biggest neighbourhood, covering about a third of the planet's surface. The ocean doesn't really end; it just runs into land, bounces off and keeps going around the world. If you followed it, you could sail around the whole planet and come back where you started, which explorers did for the first time about 500 years ago. It took three years. Most of the crew didn't make it. Bring snacks.

808. Can I drink seawater if I add sugar?

No. You'd just make sweet, salty water and still be thirsty. Seawater has so much salt that drinking it makes your body lose more water than it gains, as your kidneys try to get rid of the extra salt. Adding sugar makes it taste like a terrible sports drink, and it's still dangerous. Sailors lost at sea have faced this cruel problem for centuries: water everywhere, and not a drop to drink. Today, ships and some countries use desalination plants to remove salt from seawater, making it drinkable. It's expensive and complicated, but it works. Sugar is not part of the process.

809. Do jellyfish have brains?

No brain at all. They've survived about 500 million years anyway, which is inspiring. Jellyfish also have no heart, no bones and no blood. They're mostly water, about 95%, with a simple network of nerves that lets them sense light, touch and movement. They drift with the currents and sting their prey with tiny harpoon-like cells. One species, nicknamed the "immortal jellyfish," can turn itself back into a baby when it's stressed or injured, starting its life over. That's a superpower. If you're ever feeling like you're not smart enough, remember: jellyfish have been thriving for half a billion years with zero brain cells.

810. How deep is the ocean?

In the deepest known spot, the Mariana Trench, almost 11 kilometres. You'd need a very long snorkel. If you dropped Mount Everest into the trench, its peak would still be more than two kilometres underwater. The pressure at the bottom is over 1,000 times greater than at the surface, enough to crush a car like a soda can. Only a few people have ever visited the bottom, in specially built submarines. Some saw strange shrimp-like creatures and even a plastic bag, which proves humans can litter anywhere. More people have walked on the moon than have visited the deepest point of the ocean. The ocean keeps its secrets.

811. Do fish have friends?

Many swim in schools. School is where everyone makes friends. Fish schools swim together for protection, moving as one big, shimmering shape that confuses predators. Some schools are huge, with millions of fish turning together like a single giant animal. Scientists have found that some fish recognize individual fish they've met before and prefer swimming with familiar faces. Cleaner fish have "customers" who come back to them regularly, like a favourite hairdresser (see question 677). Some fish even cooperate with other species to hunt. So yes, fish have friends. They just don't have birthday parties. That we know of.

812. Is a mermaid half fish or half lady?

Both halves are equally confusing for the dentist. And the doctor, and the tailor, and whoever has to decide whether she goes to the vet or the clinic. Mermaid legends exist all over the world, from ancient Syria to Scotland to the Caribbean. Some historians think sailors who'd been at sea far too long mistook manatees and dugongs for mermaids. That says more about the sailors than the manatees. Christopher Columbus reported seeing three mermaids and said they were "not as pretty as they are depicted." They were manatees. Manatees have never forgiven him.

813. Why do dolphins smile all the time?

Their faces are shaped that way. They might be having a bad day and nobody can tell. A dolphin could be furious about a parking ticket, and everyone would still say "aww, it's so happy!" Dolphins are very smart, social animals that live in groups, play games, surf waves and even give each other names in the form of signature whistles. They also sleep with one half of their brain at a time, keeping one eye open, so they can keep breathing and watch for danger. That means they're always half-awake, and still smiling. That's the face of someone who's had too much coffee (see question 772).

814. Can a shark smell one drop of blood in the whole ocean?

No, but sharks can sense very small amounts nearby. Don't test it. The "one drop in the whole ocean" story is an exaggeration; a shark can detect blood in about the amount of water in a swimming pool, which is still very impressive. Sharks also sense electrical signals from other animals' heartbeats using special pores on their snouts. They have senses humans don't have. And yet, most sharks are not interested in people at all; we're bony, confusing and not as tasty as seals. You're far more likely to be injured by a vending machine (see question 368) than a shark. That's a real statistic. Vending machines are the real predators.

815. Do lobsters live forever?

They can live a long time and keep growing, but not forever. They still have deadlines. Lobsters keep moulting their shells as they grow, which takes a lot of energy, and eventually they get too old and tired to moult, which leads to trouble. Some lobsters have been estimated to be over 100 years old. The biggest lobster ever caught weighed about 20 kilograms, about the size of a medium dog. A lobster that big would be a terrifying pet, but excellent at opening jars. Lobsters also taste with their feet and have blue blood. They're basically tiny aliens. With claws. Respect the lobster.

816. Is the ocean deep because it's sad?

The ocean is deep because it has a lot on its mind. It doesn't want to talk about it. It's been around for about four billion years, it covers 71% of the planet and everyone keeps throwing things in it (see question 817). It's been sailed on, fished in, polluted and written about in a thousand sad songs. If anyone has a right to be deep, it's the ocean. Scientifically, the ocean is deep because of how Earth's crust formed, with heavy rock sinking lower to make huge basins that filled with water. But the emotional explanation is more relatable. The ocean just needs a hug. Ask an octopus (see question 803).

817. What's at the bottom of the ocean?

Mud, strange fish, shipwrecks, and about 4 billion sunglasses people dropped off boats. There are also anglerfish with glowing lures on their heads, giant squid with eyes the size of dinner plates, tube worms living around boiling-hot volcanic vents and blobfish, which look like grumpy old men made of jelly. The ocean floor also contains sunken treasure, lost cargo containers full of rubber ducks and sneakers and an estimated three million shipwrecks. Scientists say we've mapped the surface of Mars in more detail than the bottom of our own ocean. There could be anything down there. Including your car keys (see question 485).

818. Can I keep a whale in my bathtub?

Only a whale of a very small rubber variety. A blue whale, the largest animal that has ever lived, can be about 30 metres long and weigh as much as 30 elephants. Its heart alone is the size of a small car, and a person could crawl through some of its blood vessels. Your bathtub is roughly 1.5 metres long. The whale would not fit. Its tongue alone would not fit. A baby blue whale drinks hundreds of litres of milk a day and gains about 90 kilograms every 24 hours. Your bathtub is for rubber ducks. Rubber ducks are a much more manageable pet. They don't eat much.

819. Why do clams clam up?

They have no other move. It's their whole personality. A clam's shell has powerful muscles that snap it shut when danger is near, and it stays that way, silent and stubborn, until it feels safe. That's where the phrase "to clam up" comes from: going quiet when someone asks you a question you don't want to answer, like "who ate the last cookie?" Some giant clams can be over a metre wide and live for more than 100 years. They don't do much. They sit, they filter water, they clam up. It's a simple life. A very peaceful one. They don't have email (see question 748).

820. Do sea turtles get lost?

They can travel thousands of kilometres and still find the beach where they hatched. Most of us can't find our car. Scientists think sea turtles use Earth's magnetic field like a built-in GPS, remembering the magnetic signature of their home beach. Decades later, the females return to that same beach to lay their eggs. Baby turtles hatch at night and scramble toward the brightest horizon, which is usually the moon reflecting off the sea. Sadly, city lights can confuse them, which is why some beach towns turn off their lights during hatching season. Turtles are excellent navigators. They don't even need a GPS voice (see question 408).

821. Are pirates still out there?

Sadly yes, though they're much less fun than the movies and have no parrots. Modern piracy is a real and serious problem in some parts of the world's oceans, involving speedboats rather than sailing ships. Navies from many countries patrol dangerous waters to protect cargo ships. The fun pirates, with eye patches, wooden legs, treasure maps and parrots saying "pieces of eight," exist mainly in movies, books and on September 19 (see question 567). The parrots, at least, are still around. They live in pet stores and jungles now. They still say "pieces of eight" sometimes. Nobody knows who taught them.

822. Do fish pee?

Yes. The ocean is a giant shared swimming pool. Don't think about it. Fish release waste through their gills and bodies, and whales produce enormous amounts of poop, which, surprisingly, is very important for the ocean. Whale poop is full of nutrients that feed tiny plankton, which then feed fish, which then feed whales. It's the circle of life, but gross. Scientists call it the "whale pump." Some researchers spend their careers studying whale poop, scooping it from the surface in nets. When people ask what they do, they say "marine biology." They do not elaborate.

823. Can I water-ski behind a whale?

Whales have declined all requests. Brent asked twice. The first time, he flew alongside a humpback off the coast of Newfoundland, honking his proposal. The whale dove. The second time, he tried to attach a rope with his beak. The whale slapped the water with its tail, soaking Brent and a boat full of tourists. Brent considered this a "maybe." Humans are also not allowed to water-ski behind whales, by law; there are strict rules about how close boats can get to whales, to protect them. Whales already have enough to deal with. Also, Brent can't water-ski. He has webbed feet. He'd be fine without skis.

824. Why does the ocean make waves?

Wind pushes the water. The ocean waves back to be polite. Wind blowing across the sea's surface creates ripples, which grow into waves as the wind keeps pushing. The longer and stronger the wind blows, and the more open water it has, the bigger the waves become. Waves can travel thousands of kilometres from a storm before crashing on a beach on a sunny day. The water itself mostly moves up and down in circles while the wave's energy moves forward. The biggest wave ever surfed was over 26 metres, in Portugal, about as tall as an eight-storey building. The surfer survived. The wave was very proud.

825. Is a pufferfish puffed up because it's angry?

It's scared. When puffed up, it looks angry, which is very relatable. A pufferfish gulps huge amounts of water to inflate into a spiky ball several times its normal size, making it hard for predators to swallow. Many pufferfish are also full of a powerful poison that can be deadly. In Japan, a pufferfish dish called fugu is prepared by specially licensed chefs who train for years to remove the poisonous parts. Eating it is the most dangerous dinner reservation in the world. Pufferfish are basically the grumpy, spiky friend who gets puffy when nervous. We all have one. Sometimes, we are one.

826. Can a sea cucumber be used in a salad?

Some cuisines do eat them. They're not cucumbers, so check before tossing. Sea cucumbers are animals, related to starfish (see question 804), and they look like sausages that gave up. When threatened, some can shoot their internal organs out of their bodies to distract predators, then grow them back later. That's the most extreme defence in nature. Others turn into goo and then turn back to solid. Sea cucumbers are a delicacy in parts of Asia, where they're dried and cooked in soups. They don't taste like cucumbers. They taste like the ocean decided to become a mushroom. Don't put one in a Greek salad.

827. Do anchors go all the way to the bottom?

Yes. Otherwise they're just very heavy decorations. An anchor sinks to the seabed and digs in, holding the ship in place with its weight and grip. In very deep water, ships often can't anchor, because the chain wouldn't reach the bottom. Big ships' anchors can weigh tens of tonnes each, with chain links as big as a person. When they drop, the noise is deafening, like a giant dropping every pot and pan in a kitchen at once. Anchors are also the most popular tattoo among sailors, along with swallows and the word "MOM." Sailors love their moms. And their anchors.

828. Why don't fish drown?

They breathe oxygen through their gills. Drowning is our problem, not theirs. Fish gulp water through their mouths and push it over their gills, which pull out the tiny bubbles of oxygen dissolved in the water. Fish can actually suffocate if the water has too little oxygen, which can happen in warm, still ponds. Some fish, like lungfish, can breathe air too. One kind of fish, the mudskipper, walks around on land using its fins and breathes through its skin. It's a fish that's basically given up on being a fish. It's halfway to becoming a frog. It hasn't decided yet.

829. Do whales sing on purpose?

Yes, and the songs can travel very far. Imagine your shower singing heard in the next province (see question 627). Male humpback whales sing long, complex songs that can last up to 20 minutes and be repeated for hours. All the males in a region sing the same song, and it slowly changes over time, like a hit single that gets remixed every season. Sometimes a new song spreads from one ocean to another like a viral video. In 1977, whale songs were included on a golden record sent into space aboard the Voyager spacecraft, so aliens could hear them. Whales are now the most famous singers in the galaxy. No Grammys, though.

830. Is the Dead Sea actually dead?

It's so salty that very little can live in it. You'll float like a cork, so that's nice. The Dead Sea, between Israel and Jordan, is almost 10 times saltier than the ocean, so salty that you can float on your back and read a newspaper without sinking, which tourists love to photograph. It's also the lowest place on land on Earth, about 430 metres below sea level. Don't get the water in your eyes; it stings like a thousand angry lemons. Some microbes do live there, so it's not completely dead. Just very quiet. Mostly napping. It's a sea that's retired (see question 749).

831. Do submarines get lonely?

They have a crew, but the Wi-Fi is terrible. As question 443 explained, submarines love the dark, but the people inside can go months without seeing the sun, the sky or a new face. Many submarines can't send messages while hiding deep underwater, so crews get only short, rare messages from home called "familygrams." Some crews celebrate special days on board, like "halfway night," with games, skits and special food. There's no window to look out of, so they put up posters of beaches. A submarine is the ultimate introvert vacation. No calls, no visitors, no sunlight. Just fish and sonar pings.

832. Can I train a goldfish to do tricks?

Yes, people have trained them to swim through hoops. Your goldfish is just choosing not to. There are kits for training goldfish to play soccer, push a ball into a tiny goal and swim through slalom courses. It takes patience, a tiny stick with food on the end and a lot of time. One goldfish trainer taught his fish to do the limbo. If your goldfish isn't doing tricks, it's not because it can't. It's because it's thinking about bigger things, like the meaning of the castle in its tank, or why there's a plastic diver who never moves (see question 746). Respect its choices.

833. Why is the sea green some days and blue other days?

Tiny algae, sunlight and mood. Water absorbs red light and scatters blue light, which makes deep, clear ocean water look blue. When the water contains lots of tiny plant-like algae called phytoplankton, it looks greener. Sand, mud and sediment can make it look brown, and coral reefs over white sand make it turquoise, like a postcard. The sky's colour reflects off the surface too, so on a grey day, the sea looks grey and gloomy. Some lakes in the Rockies are bright, glowing turquoise because of fine rock dust. The ocean changes outfits every day. It has a lot of clothes.

834. Do fish ever get water in their eyes?

All the time. They've made peace with it. Fish eyes are built for water. They're rounder than ours, so they can focus underwater, and they're constantly bathed in water, which keeps them moist. Our eyes sting in water because of salt or chlorine, and because our eyes are made for air. That's why swimmers wear goggles and fish don't. A fish wearing goggles would look very silly. A fish in air, on the other hand, gets dry eyes, which is a whole different problem. So fish don't get water in their eyes. They just have eyes in their water. It's a subtle difference. Think about it.

835. Is it rude to swim next to a shark?

Not rude. Just very optimistic. In some places, people swim with whale sharks, the biggest fish in the world, which are gentle filter feeders that eat plankton and are basically giant, polka-dotted vacuum cleaners. That's safe and amazing. Swimming next to a great white shark is a different story. Shark cage diving lets people look at great whites from inside a metal cage, which is like visiting a lion at the zoo, except you're the one in the cage. Most sharks avoid people (see question 814). If one approaches, swim calmly away. Don't splash. Don't hum the famous shark movie music. That doesn't help.

836. Can I surf on a tsunami?

No. A tsunami is not a wave for fun. Stay on land and stay far away. A tsunami isn't a normal surfing wave. It's a massive surge of water caused by an underwater earthquake, landslide or volcanic eruption, and it can travel across oceans as fast as a jet plane. In deep water, it may only be a small bump, but near shore it rises into a wall of water that floods far inland. If you're near the coast and the ground shakes or the sea suddenly pulls far back from the beach, head for high ground immediately. This is the one serious answer in this chapter. Please remember it.

837. Why do seagulls steal fries?

Seagulls believe all fries belong to the beach, and the beach belongs to them. They're smart, bold and patient, and they have learned that humans with paper bags mean food. Some gulls have been seen watching people eat and choosing the moment to swoop, like tiny feathered pickpockets. Studies have found that gulls pay attention to what food humans touch, and are more likely to go after it. In some seaside towns, gulls have stolen ice cream cones, sandwiches and even a whole pizza. They are the geese of the sea. Brent respects them professionally, though he says they lack "honk."

838. Are icebergs mostly underwater?

About 90% of an iceberg is underwater. It's very private. That's where the phrase "tip of the iceberg" comes from: what you see is only a small part of something much bigger. Icebergs break off glaciers and drift through the ocean, sometimes for years, slowly melting. Off the coast of Newfoundland, there's a stretch of water called "Iceberg Alley" where people watch huge icebergs float by every spring. Some locals harvest pieces of icebergs to make iceberg water and even iceberg ice cubes for fancy drinks. That ice is about 10,000 years old. Your drink is older than history (see question 551).

839. Do octopuses have nine brains?

One central brain and a cluster of nerves in each arm. Each arm has opinions. About two-thirds of an octopus's neurons are in its arms, not its head, so each arm can taste, touch and react on its own, almost like eight helpers who sometimes disagree. Octopuses also have three hearts and blue blood, and they can change colour and texture in an instant to blend into rocks, coral or sand. They're so clever and so strange that some people jokingly call them "aliens of the sea." They're also excellent escape artists (see question 803). Keep your aquarium lid closed. Lock it, ideally. They can open locks.

840. Can I pet a stingray?

In some aquariums, yes, gently. They like it about as much as cats do. Some aquariums have touch pools where stingrays swim past and you can stroke their backs with two fingers. They feel like wet velvet or slippery mushrooms. The rays at these pools have usually had their barbs trimmed for safety. In the wild, stingrays are shy and usually only sting if stepped on. That's why people at some beaches do the "stingray shuffle," sliding their feet along the sand so rays can swim away. It looks silly. It's very effective. It's the most important dance you'll ever learn at a beach.

841. Is the ocean the Earth's bathtub?

Yes, and it's never been cleaned. Well, it cleans itself, sort of, with currents, tides and billions of tiny creatures filtering the water. But people keep adding things, like plastic bottles, fishing nets and the sunglasses from question 817. Somewhere in the Pacific, there's a huge area where floating plastic collects, nicknamed the Great Pacific Garbage Patch. People and organizations are working on cleaning it up, with boats, nets and inventions. So the ocean is Earth's bathtub, and humanity is the sibling who leaves a ring around it. Pick up your trash at the beach. The ocean will thank you. Quietly. With waves.

842. Why do I find sand in my shoes a week after the beach?

Sand is clingy. It wants to come home with you. It hides in shoes, socks, pockets, car seats, bags, towels, hair, ears and places you didn't know you had. You'll find sand in your shoes a week later, a month later and, in some cases, years later, when you pull out a beach bag in the winter. Some people believe sand multiplies like coins in a jar (see question 390). Every grain of sand is a tiny piece of rock, shell or coral that has been tumbled by waves for thousands of years. It's very old. It has seen a lot. It just wants to visit your living room.

843. Can a narwhal pop a balloon?

It has a long tusk, so yes. Don't invite one to a party. A narwhal's tusk is actually a long tooth that grows through its upper lip in a spiral, and it can be up to three metres long. It's packed with millions of nerve endings, so it may sense temperature, pressure and saltiness in the water. In medieval times, narwhal tusks were sold as "unicorn horns" for huge sums of money, and kings drank from them, believing they protected against poison. Narwhals live in the Arctic, including the waters of northern Canada. They're the unicorns of the sea. They'd be great at a party, except for the balloons.

844. Do clownfish tell jokes?

They live in anemones, which sting. Their life isn't funny, so no. A clownfish has a special slimy coating that protects it from the anemone's stinging tentacles, so it can hide there safely while predators get stung. In return, the clownfish cleans the anemone and chases away fish that might eat it. It's a roommate arrangement. Clownfish are also all born male, and the biggest one in a group can turn female when needed. That's a strange family structure, but it works for them. Despite the name, clownfish are not clowns. They don't do balloon animals (see question 635). They don't even have tiny cars.

845. What do sharks eat for dessert?

Nothing. Sharks skip dessert. That's why they're so cranky. Sharks have been around for over 400 million years, longer than trees, dinosaurs and Mondays (see question 722), and in all that time not one has tried cheesecake. Some sharks eat seals, some eat fish and the biggest sharks eat tiny plankton, which is basically ocean salad. Tiger sharks are famous for eating strange things, and scientists have found licence plates, tires and boots in their stomachs. Maybe they're looking for dessert. They haven't found it yet. Somebody throw them a cupcake. From a boat. From very far away.

846. Is a tide pool a pool for the tide?

Yes. It's where the tide leaves things when it's done playing. When the tide goes out, pools of water are left behind in the rocks, full of sea stars, crabs, sea anemones, snails, tiny fish and the occasional confused shrimp. Tide pools are like little aquariums with no glass. The creatures inside have to survive heat, cold, crashing waves and curious children. If you visit one, look but don't take, and put any rocks you flip back the way you found them. That rock is someone's house. The crab in this book grew up in a tide pool. It considers it a humble start. It's very proud of how far it has come.

847. Do lighthouses get lonely?

They talk to ships all night with flashing lights. It's a long-distance friendship. Each lighthouse has its own unique pattern of flashes, called a light characteristic, so sailors can tell which lighthouse they're looking at, like recognizing a friend by their laugh. Lighthouse keepers used to live in them, often with their families, on lonely rocks and islands, keeping the light burning through storms. Most lighthouses are automatic now, and the keepers are gone. Some lighthouses have been turned into hotels, museums and vacation rentals. You can sleep in one. It'll be very romantic. And very windy.

848. Can fish see in the dark?

Many deep-sea fish make their own light. They brought a flashlight. This is called bioluminescence, and it's used to find food, attract mates, confuse predators and light up the darkest parts of the ocean like a disco (see question 464). The anglerfish dangles a glowing lure in front of its face to attract prey, then gulps them up. Some fish have huge eyes to catch every bit of light. Others have given up on eyes entirely. In some places, tiny glowing plankton make waves sparkle blue at night, and swimmers glow with every stroke. It's one of the most magical things on Earth. Go see it once.

849. Why does my ear feel full after swimming?

Water is camping in it. Tilt your head and give it a reason to leave. Water gets trapped in your ear canal, making everything sound like you're underwater, and your own voice sounds weird in your head. People try many techniques to remove it: hopping on one foot with their head tilted, pulling their earlobe, lying on their side and making strange faces. These look ridiculous, especially in public at a pool. Eventually, warm water will trickle out suddenly, feeling amazing. If it stays for days, see a doctor, because it can cause "swimmer's ear." Never stick anything inside your ear. Not even a tiny fish.

850. Is there a fish who has read this book?

One. It claims it forgot everything in 3 seconds, which, as question 786 proves, is a myth. It remembers. It's just embarrassed. The fish is a goldfish named Captain Bubbles who lives in a dentist's waiting room in Halifax. Someone left the book open next to the tank, and Captain Bubbles read the whole thing through the glass over several months. Its favourite answer is the one about mermaids (see question 812). It has opinions about the shark chapter. It disagrees with question 845; it says it skips dessert by choice. It would like to be in the movie (see question 650).