NOSE Emmanuelle Figueras
Claire De Gastold
KNOWS Wild Ways Animals Smell the World
Superheroes of smell
1. Noses of all shapes and sizes
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hich animal has the best sense of smell? For a long time, scientists classified many animals into two groups, based on how well they smell. Macrosmatic species have large, folded olfactory membranes, containing smell receptor cells. This allows them to detect lots of different smells. Microsmatic animals have smaller, less effective membranes. But the full story isn’t quite that simple.
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ll mammals have noses, but not all noses have the same shape or even the same name! Elephants smell with their trunks. Pigs, bears, and tapirs have snouts. Dolphins and sperm whales use a rostrum. Dogs have muzzles, and cows and bison have muffles. ir
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Research has proved that, even if its sense of smell isn’t great, every animal uses its abilities differently, according to its basic needs. For example, sharks use their sense of smell to find food, seabirds use theirs to find their way, and bees use theirs to recognize each other.
If world championships were held for the best sense of smell, elephants would probably take the top spot. These mammals have been studied closely by scientists. They have found that their olfactory system is five times better than ours and twice as powerful as a dog’s. Following them closely in second and third place are pigs and mice.
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A nose for dinner
Picking up the scent
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f you could unfold it, a dog’s olfactory membrane would be the size of a handkerchief (about 30 in2 or 200 cm2). In comparison, a human’s would only cover the area of a couple of stamps. Thanks to their outstanding sense of smell, dogs can detect events we’re not even aware of.
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reat white sharks are the world’s largest predatory fish. Nothing gets past them! These “swimming noses” can detect prey more than half a mile away.
wes live in flocks and mate with rams in the autumn. This means that dozens of lambs are born at the same time in the spring. The mothers have a foolproof method of working out which lamb is theirs. Immediately after a lamb is born, the ewe spends a long time licking her baby. She washes it and encourages it to stand up, so that it can join the rest of the flock. She also uses this first moment of contact to memorize its newborn smell. This has to happen very quickly because after six hours the special smell disappears, and the lamb’s mother could reject it.
Superpowers up information Dogs’ noses pick future events about past and floating in from the smells ple, they can the air. For exam a was parked in tell that a car ier, or that earl spot r particula an is about to a pregnant wom er. corn come round the
A drop of blood in the ocean Sharks have nostrils at the end of their snouts. But instead of being used for breathing, they are only used for sniffing out scents. Each nostril is independent of the other, so sharks can detect two smell trails at the same time. Water constantly enters the sharks’ nostrils. There it’s analysed analyzed by millions of neurons that send information back to their brains. Even at very low concentrations, molecules in blood, meat meat,or orskin skincan cantrigger trigger sharks to take immediate action. So fish better watch out!
The incredible feat of the red kangaroo
Standing out from the crowd
For the first few days, this smell is used as an “access code” for feeding. When the lamb approaches its mother, she sniffs it to identify it. She will only let it feed if she recognizes the smell of her own baby lamb.
A drop of blood in the ocean Sharks have nostrils at the end of their snouts. But instead of being used for breathing, they are only used for sniffing out scents. Each nostril is independent of the other, so sharks can detect two smell trails at the same time. Water constantly enters the sharks’ nostrils. There it’s analyzed by millions of neurons that send information back to their brains. Even at very low concentrations, molecules in blood, meat, or skin can trigger sharks to take immediate action. So fish better watch out!
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nlike other mammals, marsupials (kangaroos, koalas, and opossums) are born before they can survive outside the protection of their mother’s body. In this state, they use smell to find their way to a pouch of skin on their mother’s belly, where they continue to grow.
A lively bea n What an unusual baby mammal ! Newborn kang aroos—called joeys—are less than 1¼ in (3 cm) long whe n they are born. With no fur, eyes, or ears and tiny feet, they look like big red beans.
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Noses of all shapes and sizes
The ant: antennae that can smell
Ants don’t have nostrils. They smell with the antennae located on their heads. These are covered with hundreds of hairs—known as sensilla—that are invisible to the naked eye. They
pick up chemical messages and send them back to an area called the antennal lobe. This is the equivalent of the olfactory bulb in a mammal’s brain. Out of all the insects, ants are
the champions of smell. They have four to five times more smell receptors than bees, flies, or wasps.
Millions of olfactory neurons
A dog’s nose is a high-tech precision instrument. It doesn’t work in quite the same way as ours does. The outside is covered with a wet liquid that traps odorant
molecules contained in the air. The inside is separated into two compartments: one to breathe and the other to smell. Where do a dog’s superpowers come from? The olfactory
Unusual newborns
membrane in its nose contains nearly 300 million olfactory neurons. We humans have only 5 million.
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The birth of the red kangaroo is so spectacular that in 1830 no one believed the scientist who first observed it. How could this tiny, blind creature find the way to its mother’s pouch on its own?
Although it can’t see, the newborn follows the smell of saliva that the mother has deposited along her belly. The climb takes a few minutes of intense effort. Using its little claws to cling to
its mother’s fur, it finally reaches the pouch. Here it latches on to a nipple, feeds, and starts to grow. Seven to eight months later, when the pouch has got too cramped, it’s time for the joey to leave!
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Nostrils at the end of their beak
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Identity checks at the hive
Telescopic tentacles
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ll birds smell and breathe through two openings at the base of their beaks—all except one, that is. The nostrils of kiwis are right at the end of their long beaks.
ith long, soft bodies, tentacles on their heads, raspy tongues, and a shell that gets bigger as they grow, snails are curious creatures! Famous for being incredibly slow, these animals don’t have an ear canal so they are completely deaf. Their eyes are on the ends of a pair of long tentacles, but their vision is very poor, even close up. However, snails have excellent senses of smell, taste, and touch, which they use to survive.
Two noses are better than one
Two noses are one better than
Snails have two “noses” at the end of their shorter tentacles. These fold and unfold to pick up smells that we can’t detect. They allow snails to smell a lettuce 330 ft (100 m) away. Although snails move at just 13 ft (4 m) an hour, they always end up finding what they want. Slow and steady wins the race!
end “noses” at the Snails have two e fold tentacles. Thes of their shorter that pick up smells and unfold to snails ct. They allow we can’t dete m) ce 330 ft (100 to smell a lettu e at just mov ls snai h away. Althoug ys end hour, they alwa 13 ft (4 m) an and Slow t. wan t they up finding wha race! steady wins the
Newborn scents
s know when e of smell, dog y Using their sens lamppost. The urinated on a another dog has female, too. it was male or n urinating. can tell whether whe cock their leg to er. er bett pref y es itor Mal terr to mark their This allows them farther the they urinate, the The higher up smell travels!
oneybees live with a single queen, who is often the mother of all of them. Her scent spreads through every member of the colony. Their hive can house more than 20,000 bees and has a highly organized social structure. Each individual bee has a role. Some are nurses, others cleaners, packers, builders, or guards. When they’re three weeks old, honeybees become foragers. They fly off to look for pollen, nectar, and water to bring back to the colony. Depending on how far the nearest flowers are, they can make up to 100 trips a day.
Protecting their turf
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pride of lions consists of several females, a few cubs, and one or two big adult males. The pride occupies a large home range that it shares with other big cats. Within this space, each pride has its own territory and won’t tolerate outsiders entering it. How do they mark their patch? By using smell, of course!
feast An exclusive y-made itory is a read The lions’ terr elles, ential prey (gaz larder full of pot rantee on) that will gua impala, and so the group. of ival surv eat, the find enough to If the pride can area and protect it will stay in the r, groups. Togethe it from other k mar it each day to the cats patrol
Precision tec hnology
Noses of all shapes and sizes 10
A shortsighted chicken
Kiwis are full of surprises. Around the size of a chicken, these birds have huge feet and stumps instead of wings. They can’t fly, so they hide in bushes to escape predators during
the daytime. At night, they roam the forests of New Zealand looking for food. They have good hearing, but poor vision, whether close up or far away. Their most important
sense is smell. Scientists have discovered that they have a much better sense of smell than many other birds.
A great model for an artificial nose
Who would have thought that we might one day use this sluggish animal as a model? In the snail’s brain is a region called the procerebrum. This area is equivalent to the olfactory
bulb in humans. This group of highly powerful neurons is what allows snails to identify smells at impressive distances. Researchers in Quebec, Canada are studying the
Scent barriers
performance of these neurons. They plan to use them to model the design of an artificial nose for detecting toxic substances in the air. 11
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Males—and occasionally females—urinate on tree trunks to mark them with their scent. They also use specialized glands under their tails, between their toes, and on their noses to spray
pheromones over the ground as they walk. These identify their age, sex, state of health, and family line. They also send a clear message to other passing lions
that they’re not welcome. If they enter the pride’s territory, they can expect a swift reaction!
Getting to know you
its borders.
Kiwis walk with their heads dow n to smell for wor ms, larvae, and insects buried in the earth. The y have two sma ll valves at the back of their nostrils that open and close automat ically, so they can stick their “nos es” into carpets of leaves and soil without sucking up dirt .
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6. Staying out of trouble M
any animals use their noses as danger detectors. If they pick up the smell of a predator, their brains automatically tell them to flee or counterattack.
So what do the predators do? Many of them get around this by concealing their own smell and taking their prey by surprise. This is why tigers hunt into the wind and dogs roll in mud.
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Playacting opossums
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hen threatened, some animals deceive their predators by producing a smell similar to a dead body. Grass snakes, ladybugs, opossums, and water stick-insects all use this same defense technique. They hide right under their predators’ noses! If Virginia opossums are attacked, they will defend themselves with their teeth. But if this fails, they drop to the ground with their eyes closed, tongues hanging out, and mouths open. They drool and defecate a greenish substance with an awful odor. To a predator, they might look dead. Is this behavior a deliberate trick, or an instinctive reaction from shock? Scientists haven’t found a definitive answer to this question.
NOSE KNOWS Wild Ways Animals Smell the World
Take a fresh sniff at the world in this odoriferous companion to the award-winning 2018 title Eye Spy: Wild Ways Animals See the World! (9781999802851). • • • •
CONTENTS The invisible world of smell 1. Noses of all shapes and sizes 2. Newborn scents 3. Sniffing out a meal 4. Stink to impress 5. Getting to know you 6. Staying out of trouble
Lemurs compete in stinkiness contests for mates. Opossums smell like corpses to confuse attackers. Mice use alarm scents to warn friends of danger. Polar bears sniff out prey hiding under the sea ice.
Learn how smell works across the animal kingdom, and lift the flaps to find out how rabbits, giraffes, snails, clown fish, lions, dogs, bees, and more use scent to find family or food, to leave messages for friends, and to warn away rivals. All you have to do is follow your nose!
7. Heading in the right direction
Author: Emmanuelle Figueras Illustrator: Claire de Gastold Format: Hardcover Price: US$21.99/CAN$29.95 Extent: 38 pages Size: 9.6 x 13 inches Pub date: October 1, 2019 Ages: 7 – 10 ISBN: 9781912920075
BISAC codes JNF051150: Juvenile Nonfiction/ Science & Nature/Zoology JNF003000: Juvenile Nonfiction/ Science & Nature/Animals JNF013060: Juvenile Nonfiction/ Concepts/Senses and Sensation
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