The rare scare

OBJECTIVES: Define endangered, threatened, and extinct. Describe several characteristics that make an animal extremely susceptible to extinction. AGES: Intermediate SUBJECT: Science MATERIALS: Copies of page 202, index cards, markers, easel paper or chalkboard.

Rhinoceroses, pandas, condors, and many other endangered species have more in common than just their endangered status. Many share characteristics that make extremely susceptible to becoming extinct. Start off the activity by passing out a copy of page 202 to each them person. Explain that each of these animals is imaginary, but each has characteristics that are similar to those of real animals living today. Have the kids read the information given for each animal, then have them decide which of the animals would be the first to become extinct as more and more people move into the area where each animal lives.

After each person has picked an animal, take a tally to see how many kids voted for each animal. Ask the kids why they picked these animals. Then explain that many animals that are threatened or endangered share one or more characteristics that make them more prone to extinction Discuss some of these characteristics, using the information below. After the discussion, have the kids look at page 202 again to see if they agree with their original choices. Then take another tally and compare the results to those of the first one.

Explain that the crested crabbit is the animal that will probably become extinct first because it has so many of the characteristics that make an animal susceptible to extinction. For example, it has a very limited range, has a low birth rate, has a very specialized diet, migrates and nests in only one type of tree. Explain that animals that have one or more of these characteristics usually do fine until people-related problems, such as habitat loss and pollution, start to affect them.

ANIMALS ARE MORE PRONE TO EXTINCTION IF THEY...

INTERFERE IN SOME WAY WITH PEOPLE'S ACTIVITIES: Explain that some animals may kill livestock, eat or ruin crops, or feed on animals that people also like to eat. And because they interfere with people's activities, these animals are often shot, poisoned, or harmed in some other way. Ask the kids if they can think of some examples (many predators, such as eagles, wolves, jaguars, and tigers as well as geese, ducks, and other birds that sometimes eat crops).

MIGRATE: Animals that migrate usually depend on several different habitat areas. Because of this, they can be very vulnerable to habitat destruction. For example, many songbirds that migrate to tropical forests in winter are in trouble because thousands of acres of their rain forest habitat have been developed into pastures, farms, towns, and roads.

HAVE VERY SPECIFIC FOOD OR NESTING REQUIREMENTS: Some animals are super "picky" about what they eat or where they live, or both. These specialized animals, which are often adapted to eating only one type of food or living in only one type of area, can become endangered if their food source or nesting site disappears. For example, the Delaware fox squirrel once thrived in the open forests that grew along the Eastern Shore of Maryland, Virginia, and Delaware. As more and more of these forests disappeared, so did the squirrels. And today the Delaware fox squirrel is listed as an endangered species.

ARE VERY SENSITIVE TO CHANGES: Many animals have a very difficult time adapting to changes in their environment. For example, birds of prey and many other animals are very sensitive to chemical changes in their environment, such as the introduction of pesticides. Other animals have a hard time competing with introduced species that have the same nesting or food requirements. For example, bluebirds-a species native to North America-have a hard time competing for nesting sites with starlings, which were introduced from Europe in the early 1900s.

HAVE SMALL BROODS AND LONG GESTATION PERIODS: Ask the kids if they can think of some animals that give birth to only one or two young every year or every two or three years (elephants, bats, condors, and so on). Explain that when the populations of these animals drop, it takes much more time for their populations to recover because of the low birth rate. And the animals sometimes become extinct before they have time to make a comeback.

Animals with low birth rates have another problem, too: They don't reproduce fast enough to produce offspring that can adapt to changing conditions. Have the kids compare the reproductive capabilities of an elephant with those of a cockroach. Explain that on the average, an elephant has about three young every 10 years and that a cockroach has 80 young every half year. Copy the following figures on the board and explain that if all the animals lived and mated, here's the number of young produced in each generation.

ELEPHANT		COCKROACH
3	1st Generation	80
6	2nd Generation	3,362
13	3rd Generation	137,842
28	4th Generation	5,651,522
61	5th Generation	231,712,403
132	6th Generation	9,500,208,482r

(Note: These figures are simplified and represent approximate numbers of individuals per generation.)

Ask the kids to compare the number of years it takes an elephant and a cockroach to produce a 6th generation. (Since an elephant has an average of 3 young every 10 years, and a cockroach has an average of 80 young every half year, it would take elephants 60 years to produce 6 generations, and only 3 years for the cockroaches to do the same. ) Emphasize that because of their high birth rate, cockroaches have more opportunities to adapt to changes in their environment.

ARE NATURALLY RARE: Some animals are rare throughout their range, and others have a very limited range. In both cases, the animals are often vulnerable to habitat destruction and other people-caused problems. For example, many of the native plants and animals that live on the islands of Hawaii are naturally rare. And as more people move into the area, many of these already rare plants and animals face habitat loss, competition from introduced species, new diseases, and other problems.

BRANCHING OUT: "PICKY" EATERS

To demonstrate why specialized animals are often more susceptible to extinction, play this action game outside. Before starting, make a set of food cards by drawing the symbols and words, shown in the chart below, on index cards. For a group of 30 kids, you should make 10 fruit, 15 leaves, 15 insects, 10 small mammals and reptiles, 10 birds and eggs, and 10 snails.

Also copy the chart on a chalkboard or piece of easel paper so the kids can see which symbol stands for which food items and which foods each team eats. Before going outside, divide the group into five teams and give each team a number. Then tell them to look at the chart to see what they eat. For example, the kids in Team #1 are animals that eat fruit, leaves, insects, small mammals and reptiles, birds and eggs, and snails. And the kids in Team #2 are animals that feed on insects, small mammals and reptiles, eggs, and snails.

Now go outside and spread the food cards in a large playing area. (It's a good idea to play this game only on non-windy days.) Remind the kids what each team can eat and what each card represents. Then have the kids form a huge circle around the playing area. When you say "go," have the kids get down on their hands and knees and crawl around the playing circle to find food. (If the ground is wet or muddy, have the kids hop instead of crawl.) Tell them to collect as many food cards as they can find, but that they should collect only the type of food they can eat. For example, the kids in team #4 would be able to collect only insects, leaves, and fruit.

"Endangered species are sensitive indicators of how we are treating the planet, and we should be listening carefully to their message." -Donald Falk

After all the cards have been collected, have the kids count how many they have. Explain that to survive, each animal needs at least two food cards. How many animals didn't find enough food?

Now play again, but explain that people have destroyed much of the habitat in the area to build an airport, shopping mall, and housing complex. Take away five of each type of food card and scatter the cards again. Which animals survived the second time? Ask the kids which animals had the hardest time surviving and why. (The animals in team #5 probably had the hardest time because they had the most specialized diet and when their food source became depleted, they would have starved. The non-specialized eaters, on the other hand, could eat another type of food when one of their food sources became depleted.) Finally, point out other examples of animals living in North America that have very specialized food or nesting requirements. (Snail kites feed on only one type of snail, Kirtland's warblers nest only in jack pines, red-cockaded woodpeckers nest only in old growth forests, black-footed ferrets feed mainly on prairie dogs, and so on.)

TEAM #	1	2	3	4	5
FRUIT	X		X	X
LEAVES	X		X	X
INSECTS	X	X		X
SMALL MAMMALS	X	X
AND REPTILES
BIRDS AND EGGS	X	X
SNAILS	X	X		X	X

ROUGH-BELLIED BEAN

* lives in hardwood forests

* feeds on fruit, leaves, insects, small, mammals, and eggs; especially fond of flitter beetles and borga beans

* has two broods per year (average number of young per brood is four)

* lives in social groups called palpals

* some groups migrate; others stay in the same area year round

ZORGAN

* lives in burrows

* is often found in hilly and mountainous areas north of the equator

* feeds on camcams, miras, and other fruits

* mates for life

* can have two or three broods per year, but usually has one; often gives birth to twins, but one of the twins usually dies

* is noted for its beautiful blue fur

CRESTED CRABBIT

* is noted for its shiny purple crest feathers
* lays two eggs every other year
* feeds on white-backed sand crabs
* huge flocks gather during the mating season
* nests in rough-barked pine trees along the coast of
* migrates each winter to a tropical island near the equator

GREEN GOOR

* lives in streams and marshes
* feeds on fish, eggs, tadpoles, and aquatic insects; especially fond of mosquito larvae
* hibernates in clusters in the mud during cold months
* lays an average of five eggs each year; eggs are sensitive to pesticide poisoning
* has been introduced into other areas to help control mosquitoes