What Does the Moon Smell Like?: 151 Astounding Science Quizzes (10 page)

their success to having evolved alongside humans.

We fell in the love with the cute, friendly ones, and thanks to our devotion, and a lack of birth control, THE

they multiplied and conquered the pet world. Cats CA

may owe their success to cat lovers, but cat lovers TCONNECTION

may owe some aspects of good health to their cats.

Animal companions can lower our blood pressure

and/or cholesterol levels, help us recover more quickly from heart attacks, and they might even help us live longer. We live with them, love them, and treat them like family members, but how much do we really know about the little cougar on the couch?

Which statement is NOT true?

a) All cats lack a sweet tooth.

b) Antarctica is the only continent with no native cats.

c) Cats can hear higher tones than dogs.

d) Most adult cats are lactose intolerant.

123

The Cougar on the Couch

Which statement is NOT true?

A

a) All cats lack a sweet tooth.

b) Antarctica is the only continent with no native cats.

c) Cats can hear higher tones than dogs.

THE

d) Most adult cats are lactose intolerant.

CA

TCONNECTION

CORRECT ANSWER:

b) Antarctica is the only continent with no native cats.

Antarctica is
not
the only continent where no native cats developed. They didn’t develop in Australia either. Humans took them to the land down under, and inevitably, some kitties went feral, and started breeding in the wild. Without any native predators, or competition, these feral cats are a serious menace to Australia’s native species. They may be good for us, but they’re not always good for the environment.

Early on in the evolution of the cat family, one of two genes for tasting sweet became inactive, and as a result, no cat, big or small, has a sweet tooth. Equally surprising is that most adult cats are lactose intolerant, which means they can’t digest milk. Cats can actually hear higher tones than dogs, but don’t bother trying to invent a cat whistle. Cats would never respond to it.

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A WOLF IN DOG’S CLOTHING

The Doggy Handshake

Dogs are a lot like us. They’re social animals who like Q

to live in a group and interact with its other members, and they have a social code of conduct for keeping things harmonious. Among humans, proper etiquette depends on your culture, but among dogs, things are a lot simpler. There’s only one unwritten book of doggy etiquette. You can train a dog to shake a paw on command, but when two dogs meet, they’re going to go by the book, and perform the not-so-secret handshake that all polite dogs know.

What is the doggy version of a handshake?

a) butt sniffing

b) ear sniffing

c) face sniffing

d) mouth sniffing

125

The Doggy Handshake

What is the doggy version of a handshake?

A

a) butt sniffing

b) ear sniffing

c) face sniffing

THE

d) mouth sniffing

WOLF

IN

DOG’S

CORRECT ANSWER:

a) butt sniffing

CLOTHING

It may not be our idea of etiquette, but it works for dogs. Ear, face, and mouth sniffing can be part of a doggy greeting, but the butt sniff is the official handshake. Each dog has an individual “scentprint” that come from glands at the base of the tail and around the anus, and wagging the tail wafts their personal aromas into the air. To make sense of those scents, dogs have a built-in decoder, a.k.a. a Jacobson’s organ. Two tiny openings in the roof of the mouth, between the canine teeth, funnel the aroma to their scent decoder and brain. With a sniff or two, they know all they need to know about the other dog —

whether it’s male or female, how old it is, its mood, and probably even the contents of the last meal in the pipe. Too much information? Not if you’re a dog, and you were born wired for smell-a-vision.

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SmellyMoon_Final 4/21/08 10:30 AM Page 127

The Wolf Within

When you look at toy poodles, chihuahuas, or dachs-Q

hunds, it’s hard to imagine that there’s a wolf within, but there is, coiled up inside every dog’s DNA.

Modern wolves, and dogs, descended from ancestral THE

wolves, and they’re still very closely related. As one WOLF

top dog expert put it, there’s less difference between dogs and wolves than between frogs in a pond. So, IN

physically they’re the same, but what about their DOG’S

behaviour? To find out, a Hungarian experiment presented dogs and socialized wolves who’d been raised CLOTHING

as pets with an unsolvable problem: a container of food that they couldn’t reach.

What did they do?

a) Both the dogs and the wolves asked the experimenter for help.

b) Neither asked for help.

c) Only the dogs asked for help.

d) Only the wolves asked for help.

127

The Wolf Within

What did they do?

A

a) Both the dogs and the wolves asked the experimenter for help.

b) Neither asked for help.

THE

c) Only the dogs asked for help.

WOLF

d) Only the wolves asked for help.

IN

DOG’S

CORRECT ANSWER:

CLOTHING

c) Only the dogs asked for help.

Once they figured out they couldn’t reach the food, the dogs wasted no time making eye contact with the experimenter and asking for help. The wolves, despite being socialized, avoided eye contact, and carried on alone. Wolves refuse to look at faces, but dogs do it all the time. Could they have learned it from us? At some point in the past — most experts think about 15,000 years ago — the dog brain developed human-friendly communications skills. But long before that, maybe even as long as 400,000 years ago, the dog’s ancestors were already hanging around near our

ancestors. As we evolved, our canine companions evolved along with us, into the astounding variety of shapes, colours, and sizes that we prefer. Today, there are more than 400 known dog breeds. They get my vote for the world’s most successful canine species.

There may be as many as half a billion dogs in the world today.

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SmellyMoon_Final 4/21/08 10:30 AM Page 129

The Brain Wagging the Dog’s Tail

Dogs don’t walk their talk, they wag it. Their tails act Q

out how they’re feeling at any given moment. To learn about the connections between a dog’s brain and emotions, and its tail, Italian researchers set up an THE

experiment with 15 male and 15 female dogs. Each WOLF

dog was put in a covered cage with a small window that it could see through, and its tail was filmed wag-IN

ging in response to its owner, an unfamiliar person, a DOG’S

male cat in a cage, and a large, dominant male dog in a cage.

CLOTHING

How did the dogs wag their tails in response to their owners?

a) all over the place

b) mostly to the right

c) mostly to the left

d) it depended on the dog

129

The Brain Wagging the Dog’s Tail

How did the dogs wag their tails in response to their A

owners?

a) all over the place

b) mostly to the right

THE

c) mostly to the left

WOLF

d) it depended on the dog

IN

DOG’S

CORRECT ANSWER:

CLOTHING

b) mostly to the right

Dog owners got the most enthusiastic response from their dogs, who wagged vigorously, with big swings toward the right side of the rump. In response to the unfamiliar person, they wagged moderately, but still to the right. Even the cat got a bit of a wag to the right, but when they saw the big, intimidating dog, their tails did a 180, and switched to wagging to the left. Dogs have two brain hemispheres. The left lobe is more about being happy and relaxed, and controls the right side of the body. When a dog’s tail is wagging to the right, it’s a happy dog. The right side of the brain is more about negative emotions, and it controls the left side of the body. When the subjects felt threatened by the big dog, their tails wagged to the left, the side controlled by the more fearful right hemisphere. Dogs also wagged to the left when they were alone. They just want to be wherever you are.

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They Just Want Whatever

You’re Having

I once heard a comic joking that whenever he took Q

the garbage out, his dog started whimpering and barking, as if to say, “What are you crazy?! Throwing out all that good food! I could eat that stuff!” At the THE

time I had a refined pooch who, thinking he was WOLF

human, ignored garbage, so I didn’t get the joke. But then along came dog number two, who, just like the IN

comic’s dog, gets frantic whenever food waste or DOG’S

compost ingredients leave the kitchen. He lives to eat, and will eat just about anything, or try to anyway.

CLOTHING

Unfortunately, dogs don’t know what’s good for them.

Do you?

Which foods are toxic to dogs?

a) chocolate, garlic, and onions

b) grapes and raisins

c) all of the above

d) none of the above

131

They Just Want Whatever

You’re Having

Which foods are toxic to dogs?

A

a) chocolate, garlic, and onions

b) grapes and raisins

c) all of the above

THE

d) none of the above

WOLF

IN

DOG’S

CORRECT ANSWER:

c) all of the above

CLOTHING

No one knows why, but grapes and raisins can cause kidney failure in dogs. Onions and garlic are good for people, but can make pets ill. A chemical in raw, cooked, or dehydrated onions causes anemia in both dogs and cats. Adding garlic to a pet’s diet is often cited as a natural way to repel fleas, but it contains the same toxic chemical as onions, so it’s not the best bet for flea control. Another food that some people think is safe for pets, but isn’t, is chocolate. All chocolate is toxic to pets, even milk chocolate, and the darker it is, the more toxic. No amount is safe. As little as half a square of baking chocolate can be lethal to a tiny dog, and only 7 squares can kill a big one. That’s on average. Some dogs are more, and some are less, sensitive. So, if your dog is hounding you for some of the chocolate that you’re eating, just say no.

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ONE OF A KIND: YOU

Your Genetic Fingerprint

You are unique. No one else is exactly like you —

Q

unless you have an identical twin. But if you’re a sin-gleton, your genetic fingerprint distinguishes you from every other person on the planet. People come in a wide range of shapes, sizes, and colours, and have wildly individual personalities, talents, and abilities. Obviously, at least some of those differences must be reflected in our genetic material, but how big a difference can there be, really?

Genetic material between humans differs by about how much?

a) 1%

b) 2%

c) 12%

d) 21%

133

Your Genetic Fingerprint

Genetic material between humans differs by about A

how much?

a) 1%

b) 2%

ONE

c) 12%

OF

d) 21%

AKIND:

YOU

CORRECT ANSWER:

a) 1%

You’re one of a kind, but the difference between you and everyone else is less than one percent. The other 99% is the same as everyone else’s genetic material.

That’s because we’re all humans and, just like every other creature, we have a genome that’s unique to our species. The human genome is made of DNA in the form of 23 pairs of chromosomes that carry our genes.

When it comes to our genes, humans are like so

many peas in a pod.

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SmellyMoon_Final 4/21/08 10:31 AM Page 135

Unravelling Your DNA

Coiled up inside the nucleus of your cells is the Q

chemical code for building, and maintaining, your entire body — your DNA. If you removed all the DNA from a single cell, you could easily fit it onto the head ONE

of a pin, with lots of room to spare. But what if you OF

unravelled it into one, long, continuous, incredibly A

thin strand?

KIND:

YOU

About far would it stretch?

a) circumference of a 33-cm (13 in) pizza

b) distance from Toronto, Canada, to Ulan Bator, Mongolia

c) height of hockey great Wayne Gretzky

d) length of an Olympic-sized swimming pool

135

Unravelling Your DNA

About far would it stretch?

A

a) circumference of a 33-cm (13 in) pizza

b) distance from Toronto, Canada, to Ulan Bator, Mongolia

ONE

c) height of hockey great Wayne Gretzky

OF

d) length of an Olympic-sized swimming pool

AKIND:

YOU

CORRECT ANSWER:

c) the height of hockey great Wayne Gretzky

Wayne Gretzky is 180 centimetres (6 ft) tall, about as tall as the human genome is long. Regardless of how different you may be from this famous hockey player, the length of your genome is the same. So the next time someone is annoying you by telling you that his or her whatever is bigger or better than yours, you can shoot back that your genome is as long as Wayne Gretzky’s (or any other famous athlete, scientist, or artist of your choice). So there!

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SmellyMoon_Final 4/21/08 10:31 AM Page 137

The Map of Your Genes

When scientists first set out to map the human