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Dogs to the rescue: canines use their incredible sense of smell to save earthquake victims.

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Striker, a golden retriever, sniffed the air as he picked his way over the ruins of a collapsed home in Haiti. Suddenly, he stopped and turned his head as if listening. Then, Striker backtracked to a space between broken chunks of concrete and began to paw and bark at the spot. It was his way of telling his handler, Scott Mullin, "There's somebody trapped alive down there!"

Mullin is a member of Florida's Task Force 1, one of the Federal Emergency Management Agency's (FEMA) elite urban search-and-rescue teams. When a massive earthquake struck the Caribbean nation of Haiti last January, his group joined others from around the world to look for survivors. Helping ,them in their search were some four-legged heroes--dogs trained to sniff out live people buried beneath debris.

Mullin's team uses two dogs to verify that they've found a person. Striker had picked up the same scent that was previously detected by Chase, a dog handled by team member P.J. Parker. With that confirmation, the team began lifting out pieces of crumbled building and cutting through a concrete floor. Nearly 45 minutes later, they finally reached a frightened 3-year-old girl who had been trapped for five days. "Striker's nose was so sensitive, he was able to detect the baby girl under all that rubble," says Mullin. Thanks to their canines' keen olfaction (sense of smell), Mullin's team safely pulled a total of 11 people from the wreckage in Haiti.

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SUPER SNIFFERS

The quake that rocked Haiti struck near Port-au-Prince, the nation's densely populated capital (see map, above). Disaster workers arriving at the city found few buildings still standing. Anyone trapped in the fallen structures wouldn't last long without food and water or if injured. Rescuers needed to work fast to free them.

Teams started searching hospitals, schools, and hotels; then they moved on to surrounding neighborhoods. At each site, the dogs were let loose to sniff for human scent. It may seem like a cute doggy habit, but "sniffing is the most effective way to sample the air," says Larry Myers, a veterinarian at Auburn University in Alabama who studies dogs' sense of smell.

With each rapid intake of air, odor molecules enter a dog's nose and travel to the olfactory epithelium (see Nuts & Bolts, p. 16). This membrane located at the back of a dog's nasal cavity contains hundreds of millions of scent-detecting cells. "Dogs have 20 to 40 times more receptor cells within their noses than we do," says Myers. That's what allows them to detect the tiniest whiff of a scent.

As odors pass over a dog's olfactory epithelium, the molecules dissolve in a layer of mucus and bind to the receptor cells. This triggers the cells to send electrical signals to the dog's olfactory bulb and other areas of the brain that analyze smells. The brain processes the signals' information and determines the source of the smell. Dogs can even distinguish the scent of a buried victim from that of the workers around them.

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OBEDIENCE SCHOOL

It takes more than a great sense of smell to be a search dog. The canines have to be friendly, athletic, courageous, and energetic. Unlike owners of a pet dog, "we want them to bark loud and jump on stuff," jokes Teresa MacPherson. She traveled to Haiti with her Labrador retriever Banks as part of Virginia's Task Force 1.

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Most of all, the dogs have to love to play. To teach their dogs to search, handlers have a person hide with the dog's favorite toy. When the dog finds the person, it gets playtime as a reward. The dogs' excitement to fend playmates is then transferred to real search missions. "They think it's an elaborate game of hide-and-seek," says MacPherson.

Before they're ready to head out into the field, though, a dog and its handier must pass a final exam given by FEMA. During the test, dogs show off their ability to follow commands, bark an alert, and navigate an agility course. The last task: searching a mock rubble pile for hidden volunteers. While sniffing the pile, dogs encounter distracting scents, such as food scraps, caged animals, and clothing. If a dog mistakes one of these for a live person, it fails.

TEAMWORK

A handier and dog get certified as a team, so only they can work together. "My job as a handler is like the pit boss of a NASCAR crew and my dog is the race-car driver," says Mullin. He works to put Striker in the best position to find scents and to keep the dog safe in dangerous environments.

Mullin carries a bottle of talcum powder he can puff into the air to determine which way the wind is blowing. This allows him to place Striker downwind of a search area--that way, scents blow toward his dog rather than away. Mullin also examines collapsed structures to gauge where people most likely could be trapped and to check the buildings' stability. In Haiti, safety was a big issue because dangerous aftershocks threatened to further collapse buildings and trap the searchers.

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"This was one of the most challenging missions I've ever been on," says MacPherson. But it was also one of the most successful. Search-and-rescue teams saved hundreds of lives that otherwise would have been lost. For their efforts, service dogs like Striker and Banks truly deserve the title of man's best friend.

nuts & bolts

Follow your nose

Dogs' and humans' noses function in a nearly identical way. The key difference: Canines' noses have 20 to 40 times more scent-detecting cells, making their sniffers an estimated 1,000 times more sensitive. Here's how dogs put their sense of smell to work.

1. A dog sniffs to allow more air to circulate in the nose.

2. Airborne odor molecules enter the dog's nostrils.

3. The odor molecules travel to a membrane called the olfactory epithelium. There, the molecules dissolve in a layer of mucus and then bind to receptor cells.

4. The scent-detecting cells send electrical impulses to the olfactory bulb and other parts of the brain.

PRE-READING PROMPTS:

* Which has a better sense of smell: humans or dogs'?

* What other animals have a good sense of smell?

* Would you want to train a rescue dog to search for missing people? What skills do you think it takes?

DID YOU KNOW?

* The Search Dog Foundation seeks dogs that come from classic hunting-dog breeds. Most search dogs are golden retrievers, Labrador retrievers, or border collies.

* A person who can't smell has a condition called anosmia.

Anosmia can be temporary, caused by a stuffed nose or infection, or it can be more permanent due to the death of the olfactory receptors or damage to other parts of the olfactory system.

CRITICAL THINKING:

* Dogs have an amazing sense of smell, and bats have excellent hearing. If you could have one sense that was extraordinary, which would it be? How would you use your newfound power? What would be the advantages and disadvantages of this supersense?

PROJECT-BASED LEARNING: LANGUAGE ARTS: Rescue dogs and their handlers possess a specific set of skills to do their jobs properly. Create a want ad either from the dog's perspective or the handler's perspective as they look for the best partner. Take it further by pairing with a partner and interviewing each other for the advertised jobs!

RESOURCES

You can access these Web links at www.scholastic.com/scienceworld.

* Learn more about what search-and-rescue dogs do at the Search Dog Foundation's Web site: www.searchdogfoundation.org.

* For more information about urban search and rescue, visit FEMA's Web site: www.fema.gov/emergency/usr.

* Want to know more about humans' sense of smell? Visit the Neuroscience for Kids Web site: http://faculty.washington.edu/chudler/nosek.html.

HANDS-ON SCIENCE (No Lab Required)

After reading "Dogs to the Rescue" (p. 14), try this activity to test your sense of smell.

PREDICT

Rescue dogs have a superb sense of smell, with hundreds of millions of scent receptors that help them locate missing people. Although humans don't have quite as many receptors as dogs, they do have a pretty keen sense of smell. Can you use this sense to distinguish among different scents? How about detecting similar ones?

MATERIALS

Mystery-scented film canisters (Teachers: See this issue's Teacher's Edition for details.)

DIRECTIONS

1> Your teacher will place one open film canister in each corner of the room. Each of these film canisters contains one of four different mystery scents.

2> Next, your teacher will give each student a film canister that contains a scent.

3> Wave your hand back and forth over your canister to waft the scent toward your nose. (Note: During this experiment, you are not allowed to talk or to tell anyone what odors you smell.)

4> Other students in the room have a canister containing a scent similar to yours. Your job as a '~rescue dog" is to walk around the room to locate these students. Do this by wafting the scents in other people's canisters toward your nose.

6> As you find other people with scents that match yours, form a group.

7> Once you are confident that you have found all of the group's members, your group needs to find the corner of the room where your "missing person is trapped." TAs a group, stop by each of the four corners and take turns wafting the smell of the canisters there toward your nose. If its odor matches that of your canisters, you have found your missing person. If not, continue to each corner until your group locates its missing person.

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CONCLUSIONS

1> As a class, discuss if some smells were easier to find matches for than others. If so, which ones?

2> Would this experiment be more or less difficult if you were to perform it outside on a windy day? Explain your answer.

3> Do you think you would have been able to detect your "missing person" if the "person" were buried under piles of rubble? Explain your answer.

Dogs to the Rescue

PRE-READING PROMPTS:

* Which has a better sense of smell: humans or dogs'?

* What other animals have a good sense of smell?

* Would you want to train a rescue dog to search for missing people? What skills do you think it takes?

DID YOU KNOW?

* The Search Dog Foundation seeks dogs that come from classic hunting-dog breeds. Most search dogs are golden retrievers, Labrador retrievers, or border collies.

* A person who can't smell has a condition called anosmia.

Anosmia can be temporary, caused by a stuffed nose or infection, or it can be more permanent due to the death of the olfactory receptors or damage to other parts of the olfactory system.

CRITICAL THINKING:

* Dogs have an amazing sense of smell, and bats have excellent hearing. If you could have one sense that was extraordinary, which would it be? How would you use your newfound power? What would be the advantages and disadvantages of this supersense?

PROJECT-BASED LEARNING:

LANGUAGE ARTS: Rescue dogs and their handlers possess a specific set of skills to do their jobs properly. Create a want ad either from the dog's perspective or the handler's perspective as they look for the best partner. Take it further by pairing with a partner and interviewing each other for the advertised jobs!

RESOURCES

You can access these Web links at www.scholastic.com/scienceworld.

* Learn more about what search-and-rescue dogs do at the Search Dog Foundation's Web site: www.searchdogfoundation.org.

* For more information about urban search and rescue, visit FEMA's Web site: www.fema.gov/emergency/usr.

* Want to know more about humans' sense of smell? Visit the Neuroscience for Kids Web site: http://faculty.washington.edu/chudler/nosek.html.

Teacher's Notes for the Hands-On Activity (p. 17)

To make the mystery-scented film canisters, you'll need: film canisters with lids (one for each student plus 4 additional ones), cotton balls (one for each student, plus 4 additional ones) * vanilla extract * vinegar lime juice * almond extract, red permanent marker * black permanent marker. masking tape

To do the night before the activity:

1. Evenly divide the cotton balls into four groups.

2. Soak one group of cotton balls in vanilla extract, the second group in vinegar, the third group in lime juice, and the fourth group in almond extract.

3. Place one cotton ball into each film canister. Then place a lid on each canister.

4. Code the canisters so that you-and only you-know which scent each canister contains. For example: put a small red dot on the bottom of the vanilla-scented canisters; a tiny piece of tape on the bottom of the vinegar-scented canisters; a piece of tape with a tiny black dot on the bottom of the time-scented canisters; and leave the almond-scented canisters as is.

To do the day of the activity:

1. To begin the activity, remove the lids from the canisters.

2. Place one vanilla-scented canister in one corner of the room, one vinegar-scented canister in a second corner, a lime-scented canister in a third corner, and an almond-scented canister in the remaining corner.

DIRECTIONS: Write "T" in the blank if the statement is true or "F" in the blank if the statement is false. If the statement is false, underline the incorrect word or phrase.

--1. When a rescue dog finds the scent of someone under rubble, it sits and stares at the spot.

--2. To be a great search dog, the dog needs to be able to bark loudly and have lots of energy.

--3. Once the molecules of an odor dissolve in mucus, electrical impulses are sent to the dog's olfactory epithelium.

--4. Dogs and their handlers are sent on rescue missions with very little training.

--5. Dogs and humans have the same olfactory sensitivity.

F 1. When a rescue dog finds the scent of someone under rubble, it sits and stares at the spot.

T 2. To be a great search dog, the dog needs to be able to bark loudly and have lots of energy.

F 3. Once the molecules of an odor dissolve in mucus, electrical impulses are sent to the dog's olfactory epithelium.

F 4. Dogs and their handlers are sent on rescue missions with training.

F 5. Dogs and humans have the same olfactory sensitivity.
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Title Annotation:BIOLOGY: SENSES
Author:Crane, Cody
Publication:Science World
Geographic Code:1USA
Date:May 8, 2010
Words:2388
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