My WHAT IF YOU HAD!? (Scholastic) books are being served with kids meal at Chick-Fil-A! Click on this photo to find out about my school visits on SANDRA MARKLE SPEAKS!

Monday, May 9, 2016


I've recently been sharing virtual Skype visits with schools. Part of my visit is a science magic show so I've been getting requests to share my secrets. I'm happy to do that because the truth is that discovering how the world works is the real magic--and what science is all about. So here goes. Follow the steps for each activity and you can make science magic too. Just be sure to check with an adult before you start. Even better ask an adult to be your partner and have fun exploring science magic together.

Make Air Pressure Hold A Plate

This could get messy so work over a sink. Even better try this outdoors. 

You'll need:
A study plastic plate
A paper towel
A sturdy plastic glass (juice size works best)

Fill the plastic glass nearly full of water. Fold the paper towel into fourths and place it on the middle of the plate. Next, turn the plate and towel over the cup like a lid. Hold the plate against the top of the cup with your fingers while you turn the whole system over.

Now the glass is on top. Be sure it is straight up and down. Hold on to the cup with the hand that isn't pressing up on the plate. Then--slowly--take your hand away from the plate. The plate won't fall and the water will stay inside the glass.

Air pressure makes this work. Even though it's invisible, air has weight and takes up space. Air is also al around you so it exerts force on you and objects and other people from all directions. As gravity pulls down on the water inside the glass a partial vacuum is created in the air-filled space inside the glass. Now the downward force of the water and air inside the glass is less than all the upward pushing force of air on the plate. You can see how much larger this surface is than that covered by the water inside the glass. The wet paper towel helps by making a tight seal between the glass and the plate. This keeps any air from slipping inside the glass. If that happened, the air rushing into the glass would push the water out. Then there would be a flood and you'd get wet. 

You'll need:
an empty 1 or 2 liter plastic soft drink bottle with a screw-on cap.
3 pushpins (the kind used to display things on a bulletin board)

Work outdoors or at the sink. Fill the bottle to the very top with water. Screw on the cap, making sure it's tightly sealed.

Next, stick the pushpins into the bottle, one at a time. Then have your adult partner hold the bottle by its cap while you carefully twist and tug out the pushpins. 

Surprise! If water leaks out at all, it quickly stops or slows to a tiny trickle.

Did the bottle magically plug the holes? Of course not. Squeeze the bottle to prove it. Water will spurt out the holes. But when you stop squeezing the water will immediately stop flowing.

The magic is that air pressure is at work again. Air doesn't simply push down, it exerts force in all directions. The force of the air pushing in on the water at the holes you made is greater than that of the water inside the bottle pushing out. 

What do you think will happen when you take the cap off the bottle, letting air push down on the water inside the bottle? Try it--just be sure the bottle is over the sink.

Make Air Vibrate and Create Squawky Cans

Want to make strange sounds? You can with a little help from science.

You'll Need:
two cans of different sizes (cleaned and dried)
Sturdy packaging twine
2 paperclips
a piece of clean sponge (about 1 inch by 2 inches)

Have an adult partner use a nail and hammer to punch a hole through the bottom of each can. The hole should be just big enough for the twine to slip through.

Next, cut a piece of twine about twice as long as the can's height. Thread one end of the twine through the hole and tie to a paper clip. Rest the paper clip on the can bottom and tape in place. Repeat these steps with the second can.

Now, wet the sponge and squeeze out the water.

To make your can squawk, hold the can in one hand. With the other hand, pinch the sponge against the string and give it a jerk. This makes the metal-can bottom vibrate. That in turn creates waves of air. When those waves reach your ear and your brain interprets the signals it hears, you hear the spooky noises.

Can you think of some other things you could make vibrate to produce squawks and weird noises? You'll probably think of lots more but here are three to get you started:

A balloon--Blow it up and grip it between your legs so you can use both hands to stretch its neck Then control how much air escapes.

A comb--Hold it in one hand and run your fingernail back and forth across its teeth.

An empty glass soda bottle--Put the rim next to your lower lip and blow a strong blast of air across the opening.

Use Fast Moving Air to Float A Ball In Mid-Air

A blowdryer makes this science magic trick happen.

You'll need:
A blow-dryer
A Ping-Pong ball

Hold the blow-dryer with the nozzle aimed straight up. You may want your adult partner to do that for you. When the dryer is switched on to "high", place the ball in this column of fast-moving air so it's about 5 inches above the nozzle. Let go of the ball and quickly take your hand away.

As long as the air current iss shooting striaght up, the Ping-Pong ball will float suspended above the dryer's nozzle.

This "magic" happens because fast-moving air has less pressure than more slowly moving air. So the Ping-Pong ball is trapped inside the column of fast-moving air. Here the ball is pushed upward by a jet of air with enough force to keep it from falling, but not enough to blow it any higher.

What you've discovered is also the basic law of nature that helps airplanes fly. When viewed on edge the upper surface of an airplane's wing is curved and the lower surface is flat. Air slips over a curved surface more quickly than it does over a flat surface. So there is less air pressure on the upper surface of the wing than there is beneath the wing, giving the airplane lift.

Can you guess why airplanes take off into the wind?

Sunday, April 10, 2016


April 27th is Babe Ruth Day. It's also the season for BASEBALL SPRING TRAINING.  So have a ball with these activities!

Do Cold Balls Bounce Less?

In 1965, the Detroit Tigers accused the Chicago White Sox of refrigerating the balls used by their pitchers.  Should a team care if their batters are pitched ice-cold balls?  You can find out.

Slip at least three baseballs  (five is even better) into a plastic grocery sack to keep things clean and chill them in a refrigerator for an hour.  While you're waiting think about how chilling changes other things, like pancake syrup or butter.  Then conduct this test to find out the cold facts.

Work outdoors on a paved area or indoors on a smooth, hard surface (after checking with an adult). Have someone hold a measuring stick straight up with the starting end of the scale on the floor.  Drop the balls one at a time from the top of the stick.  Be sure someone is watching closely to check exactly how high each ball bounces.  Write down each ball's bounce height. Divide by the number of balls tested to find the average bounce height.

Next, spend five minutes warming up the balls using anyway you can think of to do the job safely, such as holding the balls in warm hands or even setting them on a hot water bottle.

Then repeat the bounce test with the warmed balls.

Were the warm balls better bouncers?  
They should be.  

How far a baseball travels when a batter strikes it depends on two things: the amount of energy transferred to the ball by the bat and how quickly the elastic material making up the ball snaps back, pushing away from the bat.  When a bat strikes a ball, it compresses the baseball to about one half of its original diameter. Wow! Think about that the next time you watch a batter connect with a ball.

For all those inquiring minds who'd like to know how this historic event effected the game, here's the rest of the story.  Before this event, Major League home teams used to supply game balls to the umpire one at a time throughout the game. So the home team's pitchers could be given chilled balls. Worse, according to the White Sox, the Tigers baked the balls given to their team's pitchers. That meant the Tigers were slugging hot balls.  To end the squabble, today, Major League rules require the home team to supply all the baseballs to be used during the game two hours before game time.

The Balls Have Changed--But Not Much
In the past 100 years, baseballs have only changed in one way. In 1974, cowhide replaced horsehide as the baseball's covering.  Otherwise a baseball is exactly the same, today, as it always was.

There's a cork core inside a rubber ball surrounded by nearly a quarter mile of woolen yarn, a winding of cotton/polyester yarn and a leather jacket sealed with 108 stitches (not one more or one less).

The finished ball must weigh between 5 and 5.25 ounces (141 and 148 grams) and be between 9 and 9.25 inches (22 and 24 centimeters) around.
This CT-scan lets you peek inside a real baseball to see its parts.
Don't you love the unique way technology lets us look at things?

Find The Sweet Spot

You'll need a wooden bat and a hammer (either a real hammer or a wooden mallet) for this activity.  Your job is to find the one special spot on the baseball called the sweet spot.  It has that name because striking a baseball with exactly that spot on the bat will make it travel farther than striking it at any other point.  That happens because striking the ball at the sweet spot causes the least amount of vibration within the wooden bat.  And that means the greatest amount of energy will be transferred to the ball.  So where is the sweet spot?

Have a partner grab the end of the bat's handle and let the bat hang straight down. Use the hammer to tap the bat gently near its fat free end.  Then repeat tapping the bat gently at points closer and closer to the handle.  Usually striking the bat at the sweet spot will produce a slightly different sound.  The person holding the bat should also feel less vibrations when the bat is struck at the sweet spot.

To be precise, measure about six inches (15 centimeters) up from the fat end of the bat.  That's where the sweet spot is usually located.

When a Major League player strikes the ball at that
spot, it's not uncommon for the ball to leave the bat
traveling 100 miles (160 kilometers) per hour.

In the past, Major League ballplayers tried to make balls travel farther by swinging heavy bats.  Home run hitting king Babe Ruth regularly used a 42 ounce (1,190-gram) bat. Sometimes, he even used one that weighed 52 ounces (1,474 grams).

Today, though, players have decided they can knock balls farther by swinging faster. So they are opting to use lighter bats--ones weighing 32 or even 28 ounces (907 or 793 grams).

Play the Original Game

This is a photograph of a game of rounders being played in 1913.

Before there was baseball, people in England played a game called rounders.  Follow these directions, to play a game of rounders. Then decide how it's similar to today's game of baseball. And how it's different.

To play rounders, first vote on how many players to have on a team--any number will do.  It's not even necessary for the two competing teams to have the same number of players.

Next, vote on whether to have three or five bases.  Once outdoors, space out the bases in a circle. They can be as close together or as far apart as you choose. The pitcher will stand in the center of this circle. The batter from the opposite team will stand at one of the bases. The other players on the pitcher's team will be in the field to try and catch the batted ball and tag the batter before he circles the bases.

Now, play ball.  Each player gets only one chance at bat.  The winning team is the one with the most players to have rounded all the bases.  By the way, in the original game, runners weren't tagged out. They had to actually be struck with a ball tossed at them.

You might be interested in knowing that in the very early days of baseball, players were given four strikes before they struck out.

Check out these websites for even more baseball fun.

The Baseball Hall of Fame   Great information about the Hall of Fame players, trivia about baseball, and Frequently Asked Questions about the game.

Black Baseball League  A place to explore the period of baseball's history when black players had their own league.

Atlanta Braves  A site to find tips from pros, interviews with players and much more. I shared this team's site because I lived in Atlanta for many years and still cheer for the team.  However, you can find information about your own favorite team at

Wednesday, March 9, 2016

While Celebrating WOMEN'S HISTORY MONTH Remember Special Wild Females

I’ll never forget the day Dr. Doug Smith, director of the Wolf Restoration Project at Yellowstone National Park told me the story of Female 7. She was one of the first wolves set free in Yellowstone in March, 1995. The first in almost seventy years, following a time when people trapped and killed wolves to eliminate this top predator from Yellowstone National Park. 

Finally, people realized, you can’t fool with mother nature. Every animal in an ecosystem has its role. Wolves helped eliminate sick, weak, and old animals keeping populations of grazing animals, like elk and deer, from becoming huge—too big for there to be enough food for them to eat.

What struck me as exciting was that the young wolf scientists called Female 7 didn’t choose to remain part of the pack people artificially created. She immediately set off into the wilderness on her own. Of course, no one knows exactly what she experienced or how she reacted. Family Pack is her story as I imagine it happened. The ending is known and we'll get to that. 

Family Pack opens with a young female wolf heading off on her own into Yellowstone National Park. There are no other wolves anywhere around. Imagine if you were suddenly in a wilderness where you were the only human. How would you feel about that? What might you find exciting? What might make you feel frightened?

For wolves, the world is given shape and texture as much by scents as by colors and shadows. Close your eyes and have a partner guide you into different rooms of your home. Can you tell where you are just by what you smell? A wolf could!

Next, close your eyes while your partner cuts or peels an orange, an apple, or a banana and hold it under your nose. Sniff this fruit. Then have your partner hide the mystery fruit so you can’t see it when you open your eyes. Use crayons or paint to color a piece of paper, sharing your impressions of this fruit based solely on how it smelled. For example, rather than using orange to show that fruit choose a color to share how sweet it smelled and make the color dark or light to indicate whether the odor was strong or faint. 

Finish by showing your picture to another family member who didn't see the mystery fruit. Can they identify whether your picture shares an orange, an apple, or a banana? Then have your partner reveal the mystery fruit and let everyone share sniffing and tasting it.

At one point in the story, the young female thrusts her muzzle skyward and howls. Where she used to live, her voice would have drawn a chorus of other wolf voices and the arrival of her family. Try it!  

Have family members scatter throughout the house. Then you move to wherever you want your family to meet up. Start your family’s chorus by tipping your head back and giving a good loud howl.  Have each family member join in with a howl that is slightly different than yours and thus uniquely their own. Each family member should also move toward you between howls. Repeat until your entirely family has found you.

Did howling help you find each other?

Did you find you were quickly able to identify each family member by their individual howl?
Imagine how you would feel if, like the female wolf in the story, you howled and your family never found you?

The young female wolf finally becomes able to catch prey to feed herself by practicing her hunting skills. Name at least five things practice has helped you learn to do better.

Finally, one day, the young female discovers she’s no longer the only wolf in her home territory. When she first meets the young male they sniff each other, rub heads, and lick muzzles. Like wolves, people have customs for greeting someone new? Think about how people you know respond to being introduced to someone.

Family Pack has a very happy ending. 

Female 7 and Male 2 mate. I suspect it was love at first sniff. When they had pups, their family pack became the first naturally formed pack in Yellowstone following the reintroduction of wolves. Scientists called it the Leopold Pack. 

Over the years since then, the Leopold Pack has grown into one of the strongest and largest packs in Yellowstone National Park. Female 7 and Male 2 are no longer living. However, their descendants continue to hunt the same territory Female 7 first claimed when everywhere she went she left the first wolf prints to mark the ground in over seventy years.

Now, isn't that one special wild female worth honoring this month!?

Friday, March 4, 2016


March Fourth is National March Forth And Do Something Day

I LOVE it because March is a "capitonym"--a word whose meaning changes depending on if it's capitalized or not. So capitalized it's this month and otherwise it means a way to walk. So, while you march on this March day, have fun with WHAT IF YOU HAD ANIMAL FEET!? 


Have each child choose his or her favorite animal feet. 

Choose some foot stomping music and have the children spread out at least an arm’s length apart. Then turn on the music and have kids dance where they’re standing. 

Remind them to dance as if they had their favorite animal feet. 

Afterwards, ask the children to tell how it was different to dance with that animal’s feet. Next, have them tell how they think it would be different to do each of these things if they had that animal’s feet.
  • Take a bath
  • Pick up their room
  • Make their bed

Now, let them pick another animal’s feet, start the music, and dance some more!


Start by having children list all the kinds of shoes they can think of. That list will include: boots, sneakers, loafers, high heels, waders, sandals, high tops—and more.

This animal's shoes will need to be big and tough!

As a class, vote on one animal from WHAT IF YOU HAD ANIMAL FEET!? to treat to their very first pair of shoes. 

Share building a list of ideas to answer these questions:
  • What should those shoes do for the animal’s feet?
  • What material will the shoes need to be made out of to fit the animal’s habitat and behavior?
  • What special features could be added to the animal’s shoes to make them extra special?  

Have the children work alone or in small groups to draw and color pictures or make models of their special animal’s new shoes.


The Rest of the Story

Have children look through WHAT IF YOU HAD ANIMAL FEET!? and pick their favorite picture of a boy or girl with animal feet. Now have them tell the rest of the story.

Each of those pictures shows only one moment in a story. Challenge children to imagine--and tell--the rest.
  • What led up to the moment shown in the picture?
  • What is really happening in the picture?
  • How is this story likely to end?

For example, look on page 19 at the boy digging for treasure with aardvark feet. How did he get the treasure map and find the right spot to dig? 
How does he feel about finding the treasure? And what kind of treasure did he find?
What will he do now that he’s found the treasure? How will it change his life?


I'm sure everyone will agree that the animals in the book  have totally cool feet. For this activity ask children to pick an animal that isn’t in the book. 

Have them dig into books and work with older students or adults to search on-line and find out about that animal. 

Most important, encourage them to find the answers to these two questions:
1. What are that animal's feet like?
2. How does the animal use its feet to move and stay alive?

Next, like WHAT IF YOU HAD ANIMAL FEET!? have children make two-pages (a left hand/right hand spread) for their animal. On one page, they should answer the two questions. On the second page, they should share at least one super fun way it would be cool to have that animal’s feet for a day.


Ask children to imagine what it would be like if one day an animal woke up with different feet. What if....
A Mountain Goat had White Rhinoceros feet?
A Cheetah had Eastern Gray Kangaroo feet?
A Barn Owl had Cheetah feet?
A Giant African Millipede had Green Basilisk feet?
A Wolf had Duck-Billed Platypus feet?

Or make up another foot swap.  

Challenge children to think of something totally cool that animal could do with its new feet. Be sure they also consider how that swap might cause serious problems.

Okay, these activities got you started. Now, MARCH FORTH and come up with even more. 
smile emoticon

Monday, February 29, 2016


Frogs of the world need you to be a science detective and help solve a scientific mystery, The Case of the Vanishing Golden Frogs. 

Scientists are  after a serial killer--one guilty of killing so many frogs that some kinds no longer exist outside of safe places, like zoos. 

So if you're ready to join the science detective task force for this case, check out a copy of the book and dig in. 

Can you identify the killer in time to save the Panamanian golden frogs?

Can you find a way to stop this killer before even more kinds of frogs become victims?

Karen Lips discovered the first frog victims. Read pages 6 and 7 to find out:

1) When did she make this discovery?
2) Where in the world were the bodies?
3) Why was it important that the dead frogs were not decayed?

Just as detectives get help from a Medical Examiner, Karen Lips turned to a pathologist, someone who studies diseases. 

Here's the clue the pathologist discovered when he looked at a sample of the frog victim's skin with a microscope. Check it out on page 8. He reported that it wasn't like anything he'd ever seen before. 

So Karen Lips decided to check out the three usual suspects that kill animals:

*Habitat (home territory) Destruction


*Climate Change

Why is habitat destruction bad for frogs and other animals?

But the land where the golden frogs lived proved to be okay and untouched.

Water pollution can kill frogs. Why was this what was killing golden frogs?

What two things did Karen Lips then check out to prove climate change wasn’t the frog killer? 

Joyce Longcore finally identified the frog killer as a chytrid fungus, a kind of plantlike living things. What did she see that let her figure out this was the killer? Dig into this on pages 18 and 19 

Because she was the first to identify this new kind of chytrid fungus, Joyce was allowed to name it. She called it Batachochytrium dendrobatidis--Bd for short.

Now that the killer's identity is known, your job is to stop it from killing more golden frogs. 

So you'll need to find out these two things about how this killer attacks its victims? Use the clues you've already discovered to answer these questions. 

1) Who's more at risk--adult golden frogs or tadpoles? 

2) In what kinds of environmental conditions is Bd most likely to kill?

Armed with that profile of the killer you can help the scientific SWAT team save Panamanian golden frogs from being killed by Bd. 

Now, find out what was done to help golden frogs survive while scientists tried to stop Bd from killing them.

Here the steps each frog went through coming from its infected habitat to its new safe site.

*Carry golden frogs in plastic bags to cleaning sites.
*Ship healthy frogs to zoos with special golden frog habitats.
*Breed golden frogs in zoo habitats to maintain the golden frog population.
*Collect both male and female golden frogs from their wild habitat.
*Treat captured golden frogs with a fungus-killing chemical for ten days.

Golden frogs aren't the only frogs at risk. Even where you live, frogs are in danger from Bd. They may also be at risk because of habitat destruction, polluted water or climate change.

It's time for you to help launch OPERATION SAVE OUR FROGS.
First, find out what kinds of frogs, such as bullfrogs or leopard frogs, live in your area. Ask a local park ranger, someone at the local library, or someone at a local zoo. 


Leopard frog

Next, learn more about each kind of local frog and make a booklet with a chapter for each local kind of frog. Draw and color a picture of it. Also tell the following information: 

*How big is an adult?
*What does it eat as an adult? As a tadpole?
*What kind of conditions does it need to live as an adult? As a tadpole?

Find out if chytrids are a problem locally and, if so, what can be done to protect the frogs. Would one of the ideas you had for getting rid of chytrids possibly work? If you think it would, share your idea with someone in your local environmental protection agency or with your teacher.

Check out these efforts being done to save frogs around the world. 

Are frogs worth so much detective work and effort?

Definitely! Without frogs there would be lots more insects in the world eating our food crops and spreading diseases to plants, animals, and people. 

We need to solve The Case of the Vanishing Golden Frogs for the sake of Panimanian golden frogs, all the world's frogs--and for ourselves.

Friday, February 26, 2016


While you're celebrating International Polar Bear here's the story behind my book about one special polar bear. Waiting For Ice (Charlesbridge) actually started, as many of my books do, while I was doing research for another book and--WHOA!--I discovered an incredible true story.

I live and write by the rule that 99.9 percent of my research information must come directly from experts who are working firsthand on the subject.  That sometimes takes me to very interesting places, like the South Pole.  Or, at the very least, it lets me talk with experts on the phone--sometimes via satellite while they're in remote places.

So while writing Animal Predators: Polar Bears (Lerner),
I had the chance to talk to Dr. Nikita Ovsyanikov. 

 Since 1990, he's spent every Arctic summer on Wrangel Island, studying polar bears.  That's no easy task. Let me set the scene for you. 

This is an aerial view of Wrangel Island during the summer and during the winter. 

Wrangel Island in winter.

Wrangle Island in summer.
It's never an easy place to live. The island is North of the Arctic Circle.  It's a rugged, windswept, storm-scoured island about half the size of Rhode Island surrounded by frigid seas.

It's no wonder the island has features with such names as Unexpected River and Doubtful Spit.  Check out this website to find out more about Wrangel Island.

So why go there to study polar bears? It's because that's the place hundreds of polars bears are stranded every summer.  All winter long, polar bears roam solo or a mother travels with her cubs. The bears take advantage of icebergs and raft-like ice floes to rest in between hunting seals, beluga whales, and other sea creatures.  Polar bears are good swimmers, but they can't swim indefinitely. So when the sea ice melts, they haul out.  They're stuck wherever they land until, once again, the sea crusts over with ice.  Because Wrangel Island is one of the few available land masses in prime polar bear territory, as many as 600 bears are stranded there every summer.

Imagine the fights that break out as the bears compete for wind-sheltered resting spots and food.  Finding something to eat isn't a big problem while the island is also home to colonies of migratory birds, such as black bellied plovers and red knots, raising their young or walruses stopping by to rest.  However, those animals leave around September. 

Normally the sea ice returns in September so the polar bears leave the island about the same time as their prey.  However,  global warming has delayed sea ice formation to as late as November.  Then the polar bears are trapped, waiting for ice.  Eventually, the only food source on the island is scraps, like the remains of a whale that washed ashore and dead birds. 

Nikita shared the amazing story of what happened in 2002, a year when the polar bears had to wait until well into November for the sea ice to return.   He said, "One day, I spotted two young cubs alone on a narrow spit of land.  The cubs were small, undoubtedly only born that year, but no mother bear arrived to feed or protect them."

Nikita watched the cubs on the spit for six days. Each day, they screamed for their mother, paced nervously, and bravely lunged to drive away adult bears that came too close. The mother bear never returned, though.  On the sixth day, Nikita discovered there was only a single cub, a young female, stood alone on the spit.  Adult polar bears will attack and kill orphaned bears so Nikita guessed that's what happened to the one cub.  He also worried what might happen to the survivor.

The orphaned cub left the spit and Nikita searched for it each day as he studied the polar bears.  He watched her bravely fend off attacks from adult bears and steal a few bites of dried walrus skin.  One day, she managed to get a dead bird all for herself.  Seeing her fight to stay alive, Nikita nicknamed the cub Tuff.  Watching Tuff became his favorite past time.  Then one day Tuff surprised him by coming to the cabin where he lived on the island. His rule was to only watch the animals, but when he caught Tuff peering longingly into the window of the storage room where he kept his supply of reindeer meat his heart melted. 

Nikita said, "To me it was like watching a child suffer.  I couldn't do it. I thought I'd give her a few happy moments in what would surely be a very short life."

 Then he kept on feeding her from time to time because the sea remained ice free that year until 
well into November. 

When the ice finally returned. Nikita packed up to head home too. The day before he left,  he gave Tuff a farewell gift--a whole reindeer carcass.  So she ate and ate.  Then, very full, Tuff waddled out onto the ice, lay down, and fell asleep. 

In the morning, Nikita looked for Tuff one last time but couldn't find her. Because the ice was broken up, he guessed Tuff must have ridden out to sea aboard a floating ice raft.  He was sure that was the last he'd ever see of the polar bear cub.  What chance could she possibly have of making it through the winter without a mother to teach her to hunt or to catch food for her. 

What a shock he had, when he came back to Wrangel Island that next summer. 

He'd barely settled in when a young adult polar bear plodded up to his cabin.  Nikita said, "I'd spent so many hours looking her in the face and taking her picture, I knew at once this was Tuff."

Tuff seemed to recognize Nikita too. All that summer, whenever she ran into him on the island, she came close and didn't run away.  She also didn't come looking for a handout. She'd learned to survive on her on. Nikita happily watched Tuff growing bigger. When the ice returned that year, she left healthy and strong.

The rest of Tuff's life remains a mystery because Nikita has yet to see her return to Wrangel Island again. He says, "I like to think Tuff's alive and well and raising cubs of her own." 

I like to think she is too.