The Dog Story
Check out all the dog pictures in this article. Now, describe a dog's looks.
Does a dog reach to your ankle or tower over your head? Are its ears pointy or floppy? Are dogs fuzzy, silky, wrinkly, curly, or weird? Dog breeds are so different from each other that dogs are all these things, and more.
More than 400 breeds belong to the species that we keep as pets: the domestic dog. Over thousands of years, all dogs--from Great Danes to Chihuahuas--developed from wolves. How did it happen? Read on to get the full dog story.
My Pet Wolf
The tale starts more than 10,000 years ago, when people began to get friendly with wolves. (Some scientists think it happened 135,000 years ago!) It probably went like this:
People began taming wolves by tossing them leftover bones and meat scraps, and raising wolf pups that had lost their parents.
Wolves are used to living and hunting with a pack. The wolves that liked the free meals adopted the humans as their pack.
The animals began to hunt together with humans and guard human homes--just as they used to defend and hunt with other wolves in their pack.
Changing Traits
Of all the hungry wolves hanging around, people kept the ones with traits that they liked, like a small size and a gentle personality. These chosen wolves began to breed with each other.
Traits like size, gentleness, and barking are partly controlled by genes. Genes are passed to babies from both parents.
For example, when small wolf pups grew up and bred with each other, many of their pups were small. Some pups were even smaller than either parent.
Early humans may have kept the smallest wolf pups and let them breed. So each generation of wolves grew smaller. In this way, many traits slowly changed to turn tame wolves into dogs.
Early dogs probably looked a lot like wolves, but with smaller bodies, teeth, and brains. The new dog species was gentler to humans than wolves were. Dogs also barked more and howled less than wolves--barking worked better to alert humans to danger.
Different Dogs
Scientists believe that domestic dogs developed after humans tamed many species of wolves, in different areas. This gave dogs a large variety of adaptations, such as thick coats in cold climates and short hair in warm spots.
Dogs living on open plains counted on speed and good vision to hunt. Dogs that hunted in crowded forests needed extra-sharp noses to sniff out their meals.
More and More Different
People were quick to put dog adaptations to use. People wanted dogs to help them hunt in forests, for example. So they bred the dogs with the best noses. Over many generations, these dogs' smelling abilities grew sharper and sharper. And dogs bred for speed became faster and faster.
As people increased the traits they liked, dogs grew so different that many new breeds formed. Super-smellers became beagles, bloodhounds, and basset hounds. The speediest dogs developed into greyhounds and whippets.
Tough, loud-barking breeds like Doberman pinschers and rottweilers were bred to guard houses. And small, fuzzy breeds like Yorkshire terriers and toy poodles were created to be cute!
Until 150 years ago, people bred strong, fierce bulldogs to watch the dogs fight with bulls. Now, bulldogs and most other dogs are bred for looks. Bulldogs are known for short legs, big heads, wrinkles, saggy lips, and gentle personalities. So that's what breeders go for!
What traits would you want in a dog? Check out "Getting a Dog?" at right for tips in finding the right dog for you.
STOP AND THINK
Why might dog breeds be more different than breeds of cats, rabbits, or other animals?
KEEP GOING!
Read about Sweetie, the world's friendliest watchdog in: Watchdog and the Coyotes, by Bill Wallace. (ISBN 0-671-89075-1)
• FOREVER YOUNG--Even when they're grown up, pet dogs are much like the wolf pups below. Most dogs stay playful and obey their master rather than fighting to take charge.
Like young wolves, dogs run up and greet their masters, trying to lick their faces. But wolf pups lick grownup wolves on the lips for a reason--so the grown-ups will vomit up a meal for them to eat. Dogs don't do that!
• HALF WOLF, HALF DOG--People breed wolves with dogs to create wolf-dogs, like the one above. There are thousands of wolf-dogs in the United States.
Though many people love these pets, others can't handle their wolf traits. Unlike dogs, wolves roam large areas, and try to become "boss" by fighting the boss wolf. So wolf-dogs often escape from yards and may attack animals or people. About 15 states have made wolf-dogs illegal, and many vets won't treat them.
Dog Safety Match-up
Strange dogs can be dangerous. But understanding their natural traits can help you predict how they'll act--and how you should act to stay safe. Match each trait at left, below, with an action at right.
DOG TRAIT YOUR ACTION
1. Dogs defend their packs A. Avoid eye contact with the against strangers. dog.
2. Wolves lift a paw when they B. Stand still if a strange dog want affection or food approaches you. from another wolf.
3. Dogs can tell who an animal C. Show the back of your hand, is, how old it is, and what with fingers facing down and what its mood is by sniffing curled in. it.
4. When dogs meet, the "boss" D. Approach slowly, letting the dog stares directly, while dog sniff you. the other dog looks down.
5. Dogs chase animals that run E. Never approach a strange dog from them, like they chase without the owner's the prey that they hunt. permission.
(answers on p. 3)
FACT: Some ancient Egyptians loved their dogs so much that they made them into mummies when they died.
VOCABULARY
domestic--tame
a breed--a type of animal, within a species
to breed--have babies
genes--chemicals inside every living thing that tell it to grow into, say, a brown-eyed kid rather than a green-leaved tree
traits--characteristics
adaptations--traits that help living things survive in their environments
Does a dog reach to your ankle or tower over your head? Are its ears pointy or floppy? Are dogs fuzzy, silky, wrinkly, curly, or weird? Dog breeds are so different from each other that dogs are all these things, and more.
More than 400 breeds belong to the species that we keep as pets: the domestic dog. Over thousands of years, all dogs--from Great Danes to Chihuahuas--developed from wolves. How did it happen? Read on to get the full dog story.
My Pet Wolf
The tale starts more than 10,000 years ago, when people began to get friendly with wolves. (Some scientists think it happened 135,000 years ago!) It probably went like this:
People began taming wolves by tossing them leftover bones and meat scraps, and raising wolf pups that had lost their parents.
Wolves are used to living and hunting with a pack. The wolves that liked the free meals adopted the humans as their pack.
The animals began to hunt together with humans and guard human homes--just as they used to defend and hunt with other wolves in their pack.
Changing Traits
Of all the hungry wolves hanging around, people kept the ones with traits that they liked, like a small size and a gentle personality. These chosen wolves began to breed with each other.
Traits like size, gentleness, and barking are partly controlled by genes. Genes are passed to babies from both parents.
For example, when small wolf pups grew up and bred with each other, many of their pups were small. Some pups were even smaller than either parent.
Early humans may have kept the smallest wolf pups and let them breed. So each generation of wolves grew smaller. In this way, many traits slowly changed to turn tame wolves into dogs.
Early dogs probably looked a lot like wolves, but with smaller bodies, teeth, and brains. The new dog species was gentler to humans than wolves were. Dogs also barked more and howled less than wolves--barking worked better to alert humans to danger.
Different Dogs
Scientists believe that domestic dogs developed after humans tamed many species of wolves, in different areas. This gave dogs a large variety of adaptations, such as thick coats in cold climates and short hair in warm spots.
Dogs living on open plains counted on speed and good vision to hunt. Dogs that hunted in crowded forests needed extra-sharp noses to sniff out their meals.
More and More Different
People were quick to put dog adaptations to use. People wanted dogs to help them hunt in forests, for example. So they bred the dogs with the best noses. Over many generations, these dogs' smelling abilities grew sharper and sharper. And dogs bred for speed became faster and faster.
As people increased the traits they liked, dogs grew so different that many new breeds formed. Super-smellers became beagles, bloodhounds, and basset hounds. The speediest dogs developed into greyhounds and whippets.
Tough, loud-barking breeds like Doberman pinschers and rottweilers were bred to guard houses. And small, fuzzy breeds like Yorkshire terriers and toy poodles were created to be cute!
Until 150 years ago, people bred strong, fierce bulldogs to watch the dogs fight with bulls. Now, bulldogs and most other dogs are bred for looks. Bulldogs are known for short legs, big heads, wrinkles, saggy lips, and gentle personalities. So that's what breeders go for!
What traits would you want in a dog? Check out "Getting a Dog?" at right for tips in finding the right dog for you.
STOP AND THINK
Why might dog breeds be more different than breeds of cats, rabbits, or other animals?
KEEP GOING!
Read about Sweetie, the world's friendliest watchdog in: Watchdog and the Coyotes, by Bill Wallace. (ISBN 0-671-89075-1)
• FOREVER YOUNG--Even when they're grown up, pet dogs are much like the wolf pups below. Most dogs stay playful and obey their master rather than fighting to take charge.
Like young wolves, dogs run up and greet their masters, trying to lick their faces. But wolf pups lick grownup wolves on the lips for a reason--so the grown-ups will vomit up a meal for them to eat. Dogs don't do that!
• HALF WOLF, HALF DOG--People breed wolves with dogs to create wolf-dogs, like the one above. There are thousands of wolf-dogs in the United States.
Though many people love these pets, others can't handle their wolf traits. Unlike dogs, wolves roam large areas, and try to become "boss" by fighting the boss wolf. So wolf-dogs often escape from yards and may attack animals or people. About 15 states have made wolf-dogs illegal, and many vets won't treat them.
Dog Safety Match-up
Strange dogs can be dangerous. But understanding their natural traits can help you predict how they'll act--and how you should act to stay safe. Match each trait at left, below, with an action at right.
DOG TRAIT YOUR ACTION
1. Dogs defend their packs A. Avoid eye contact with the against strangers. dog.
2. Wolves lift a paw when they B. Stand still if a strange dog want affection or food approaches you. from another wolf.
3. Dogs can tell who an animal C. Show the back of your hand, is, how old it is, and what with fingers facing down and what its mood is by sniffing curled in. it.
4. When dogs meet, the "boss" D. Approach slowly, letting the dog stares directly, while dog sniff you. the other dog looks down.
5. Dogs chase animals that run E. Never approach a strange dog from them, like they chase without the owner's the prey that they hunt. permission.
(answers on p. 3)
FACT: Some ancient Egyptians loved their dogs so much that they made them into mummies when they died.
VOCABULARY
domestic--tame
a breed--a type of animal, within a species
to breed--have babies
genes--chemicals inside every living thing that tell it to grow into, say, a brown-eyed kid rather than a green-leaved tree
traits--characteristics
adaptations--traits that help living things survive in their environments
GETTING A DOG?
If you're thinking of getting a dog, a pet store may not be the best place to look. Pet stores often buy dogs from "puppy mills"--breeding centers that produce many puppies. Puppies in puppy mills often have cramped, dirty cages and little human contact. Many get sick or become bad-tempered.
You can choose between a purebred (single breed) dog and a mongrel (a mixture of two or more breeds). Many purebreds are healthy, but some have problems that are genetic (passed from generation to generation). Mongrels have fewer genetic health or personality problems.
You can find all kinds of dogs at shelters like the Humane Society. Or, get a purebred from a rescue organization that saves dogs from unhappy homes.
To find out which breed might be best for you, check your library for books about dog breeds. Or check out this Web site and click on "Selectapet": http://www.petnet.com.au/
By: Finton, Nancy, Nourie, Dana, Scholastic SuperScience
posted by James at 5:57 AM
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