Teacher/Student Learning Packet - Wildlife
- Learners will be able to identify several types of local plant and animal life.
- Learners will recognize the "food chain" concept.
- Learners can list the endangered animals of the Black Canyon site.
LIFE IN THE DESERT:
A quick glance at the desert might have the appearance of a lifeless environment. Yet, the Mojave Desert is alive with plants, animals, insects, fish and reptiles which have all adapted to the desert climate. The desert environment meets their needs for:
FOOD - Each type of animal will only eat certain foods. Some plants provide more nutritional value than others. Both the quantity and quality of the food are important.
WATER - All wildlife needs water. There are many water sources such as rain, dew, snow and moisture in food.
SHELTER - All wildlife needs cover for protection while feeding, sleeping, playing, traveling, etc. Cover can come in many forms, for example: vegetation, burrows, and rocks.
SPACE - Overcrowding leads to competition among animals looking for food, water, and shelter. For this reason, only a set number of animals can live in an area.
The desert is a delicate land of plant and animal life dependent on each other for their survival. The following pages identify and describe some of the most commonly found plants and animals in the desert area surrounding Hoover Dam.
OUR ENDANGERED WILDLIFE:
Small changes created by man can disrupt the delicate balance of nature in the desert. The tortoise, bonytail chub, and razorback sucker are examples of life endangered by man's intrusion in the environment.
Desert tortoises are easily recognized by their thick, elephant- like legs. Their front legs are larger than their rear legs in order to dig burrows. This is an important activity in the life of a tortoise because burrows protect them on hot summer days. They also hibernate in these burrows during the winter.
The desert tortoise is a herbivore, meaning it eats only plants, such as grasses, blossoms, and cactus. It can be found grazing in the mornings and late afternoons to avoid the heat of the summer sun. Desert tortoises can live to be 100 years old. Female tortoises normally lay four to six eggs during the month of June. The eggs are deposited in a shallow hole and covered with dirt. The eggs take several months to hatch.
Bonytail chubs and razorback suckers are endangered species which should be reported to National Park Service, U.S. Fish & Wildlife Service or Nevada Division of Wildlife, and thrown back into the water if caught.
ANIMALS OF THE AREA:
Nevada's most famous animal is the bighorn sheep. It is the official state animal. You can often see these magnificent animals near Hoover Dam. Adult males, called rams, weigh from 150 to 200 pounds. Females, called ewes, are somewhat smaller. Baby sheep are called lambs and are normally born in May or June. Bighorn sheep are surefooted animals that can swiftly climb the mountains in which they live. They use their speed to escape from predators, such as mountain lions. Bighorns are brown to grayish-brown with white rumps. Rams have large, curled horns. Ewes have smaller, straight horns.
Bighorns normally travel in herds, led by the oldest ewe. Rams separate from the herd during the summer months. The males return to join the ewes and lambs in the fall. All bighorn sheep have horns that grow throughout the animal's life. As the sheep grow older their horns grow distinct rings, one for each year. Counting these growth rings will tell you the bighorn sheep's age. Bighorn sheep can live as long as 14 years. Telling the age of a ram is easier than determining the age of a ewe. This is because the horns of a ram are larger than a ewe's and have more growth during the year. Therefore, the rings on a ram's horns are larger and more distinct.
Coyotes are carnivores, or meat eaters. Coyotes are gray or rusty gray with white throats and bellies. Adult coyotes weigh between 20 and 50 pounds. They are fast runners and can easily outrun any human. When running, the coyote holds its tail between its hind legs.
In southern Nevada, the coyotes usually eat rodents, rabbits, lizards and birds. Coyotes will eat berries if there is no other food available. They will also eat animals that have been killed by automobiles and whatever food they can find in garbage dumps.
ANTELOPE GROUND SQUIRREL
You can identify the antelope ground squirrel by the white lines running down each side of its gray body. Its cousin, the chipmunk, lives at Mount Charleston. Antelope ground squirrels are well adapted to southern Nevada's desert climate. They are able to let their body temperatures rise to high levels. Because of this, they are often the only living creatures you will see in the desert during hot summer days. These squirrels dig burrows where they go to cool off. They will also hibernate in their burrows if forced to by harsh weather. Their favorite foods are green plants and insects. Their predators include hawks, falcons, and coyotes.
This animal averages in length from 24 to 31 inches long. The body is catlike and the face is fox-like. The cat has a long, bushy tail with black and white bands around it. The ringtail cat is found in the rocky canyon areas like where Hoover Dam is located.
LITTLE BROWN BAT
The bats most frequently found in the area of Hoover Dam are grayish to dark brown in color and average in length from 3 3/4 to 3 5/8 inches. They live in the tunnels and caves in the surrounding canyons. The bats help pollinate desert plants and eat small insects.
Roadrunners are very common to Southern Nevada. The greater roadrunner is a big bird with a long tail and bill. It has a bushy crest on its head. Greater roadrunners are fast runners who seldom fly. A roadrunner is often seen running with its neck outstretched and its tail held out flat. They are ground dwellers that hunt lizards, snakes, birds, and invertebrates.
This large graceful bird can be seen soaring at great heights above southern Nevada. Adults measure up to three feet long. They are brown with a white tail band and feathered legs. Eagles usually build their nests on suitable cliff ledges or, less frequently, in trees. Their prey includes rabbits, mice, and injured water birds.
Everyone who lives in Southern Nevada has seen this bird, but few know its name. The bird has a beautiful song that can be heard when it echoes off canyon walls. The adult wren is about 3-4 inches long. It has a white throat and breast and a brown belly. The little wren eats gnats and seeds of desert plants.
This is one of four types of quail found in Nevada. The others are the California quail, mountain quail and scaled quail. Gambel's quail are easily identified by tufts of feathers, called topknots, on their heads. They can often be seen in vacant lots around the Las Vegas Valley. Their food consists mostly of seeds and fruit.
The turkey vulture varies in length from 26 to 32 inches with a wingspan of 72 inches. Its color is brown-black all over with an unfeathered head. Sometimes this bird is referred to as a "buzzard". They serve as scavengers of the desert by eating carcasses of dead animals.
This bird is all black and ranges in sizes from 19 to 21 inches. The raven has a heavy bill, wedged shape tail and long throat feathers. The bird is found in areas of mesquite and it needs trees or power lines for nesting.
Scorpions are found all over the world, but most like to live in warm, dry climates such as the desert. Scorpions have pincers and a long tail with a stinger at its tip. Though they have many eyes, they do not see well. When running, they hold their pincers out. Males have broader pincers and longer tails than females. Like wolf spiders, scorpions feed at night on insects. The mother carries her babies on her back until they shed their first skins. Scorpions sting to defend themselves. Never touch or play with a scorpion!
Desert tarantulas can get as large as four inches long. They have brownish black, hairy bodies and legs. Female tarantulas may live for 20 years. In the day, tarantulas hide in holes or under stones. In the dim light of sunset or near dawn, tarantulas come out to hunt food. They eat insects, lizards and other small animals. Tarantulas do not like to attack humans. Usually their bite is no more poisonous than a bee sting.
The Tarantula Hawk is a velvety black wasp with orange wings. It depends on the tarantula for its survival. Here's how: The female tarantula hawk paralyzes the spider with its stinger. Then she quickly digs a large hole. Next, she drags the spider inside. lays an egg, then covers the hole. When the egg hatches, the larva feeds on the spider. When it is full grown, the tarantula hawk feeds on plant nectar.
This snake varies in size from 24 to 51 inches. It has uniform white scales surrounding brown diamonds on its back from the midline to its tail. The upper half is greenish brown to olive green. You may find this snake in areas where mesquite, creosote and cacti are prominent. Its venom is extremely toxic. Keep your distance!
The average length of this lizard is 11 to 16 1/2 inches in length and it is very obviously potbellied. Its skin is loose and floppy. These lizards are seen around large boulders or rocky areas and live strictly on leaves, flowers, buds, and fruit.
PLANTS OF THE AREA
Perhaps the most recognized cactus in Las Vegas is the barrel cactus. It is not hollow, as many believe, but has a spongy pulp inside. When growing, most barrel cactus lean to the South. It is also known as the bisnaga, red barrel, fire barrel, solitary barrel and compass barrel cactus.
This cactus has flat, greenish jointed stems with rose or lavender flowers from March to June. The height is 6 to 12 inches and frequently found in dry, rocky desert flats or slopes. The beavertail cactus looks like the prickly pear, but does not have long spines. It has tiny hair-like spines instead.
The cholla (pronounced "cho-yah") cactus has jointed stems that are tubular. These joints can break off and take root in the ground to grow a whole new cholla cactus. After the plant dies, a skeleton of "ventilated wood" remains in the desert. There are many different kinds of cholla in the Mojave Desert.
This large shrub has small, round leaves which look and feel oily or sticky. This coating called "lac", helps to keep water from being lost to the dry air. Indians used lac as glue. Mexicans called this plant, "little stinker".
The mallow is common to roadsides and vacant lots. This plant has orange flowers and fuzzy leaves. The star-shaped hairs may get in your eyes if you handle the plant. That is why it is called the "sore-eye poppy".
This common plant has inch wide yellow flowers. These flowers look like small sunflowers on tall stalks. The marigold's fuzzy leaves grow at its base.
The flowers of this small colorful plant are barely visible. A "brush" of bright orange or red surrounds the tiny flowers. The top of the plant looks as if it has been dipped in paint.
PRICKLY PEAR CACTUS
There are many kinds of prickly pear cactus (nearly every state has a native species). Most can be recognized by flattened stems, called pads, that grow from joints. Indians would carefully scrape or burn off the spines and cook the pads for food. The egg-shaped fruits, called "tunas", can still be found in some grocery stores.
This plant is found in dry, rocky places or on canyon walls in the desert. A rounded, bushy plant with stinging hairs and flowers, blooms from April to June. The flowers are cream or pale yellow in color. Do not pick the flowers -- the stinging hairs are vicious!
This plant is unusual for the desert. The datura is vinelike with large, grey-green leaves. The flowers look like large white trumpets, several inches long. It is sometimes called the "moon-lily", because the flowers open at night. This is when the Giant Sphinx Moth pollinates the flowers. It is also known as "jimson-weed" or "thornapple" because of its round, spiny seed pod. All parts of this plant are poisonous.
FISHING IN LAKE MEAD AND ON THE COLORADO RIVER
Bait: anchovies, shad, and lures at different depths (seasonal). It is found in the Overton Arm, Las Vegas Bay, and Temple Bar.
Bait: minnows, worms, insects, crayfish, flies (wet or dry), and popping bugs. The "big ones" live near the canyon walls.
Bait: cheese and marshmallows. This trout likes deeper levels and cold water.
Bait: night crawlers, minnows, and lures. Largemouth bass are more active at dawn and dusk and prefer weedy areas and shoreline.
Bait: natural or prepared stink baits. They can be identified easily by their large whiskers. Bottom fishing is best at day or night.
It is usually found in pools along the edges, usually around mud, sand, and debris. This small fish is used for bait.
Its body is short, stocky and narrow. It lives in vegetated lakes and muddy rivers. Bait: night crawlers, red worms and small lures.
Bring into class a dried branch, common to the Lake Mead Recreational Area. (Choose a large, interesting branch.) This branch should be hung on a bulletin board or planted in a container. The student will draw, color and cut out a bird found in this region. A report on their habitat might be presented orally to the class.
To incorporate plant and wildlife into the above project, create a model desert scene from materials available to students (such as clay, plaster of paris, leaves, branches, paper, Styrofoam, etc.). Include reptiles, birds, and mammals in as many habitats as possible.
Desert tortoises may drink up to 40% of their weight in water per day. Select some desert plants and weigh them while they are fresh to determine how much water is in the plant. Dry the plant and reweigh. You may now calculate how much water weight is in the plant.
Weigh a desert tortoise and calculate how much water he might consume in a day and how much he must eat to provide sufficient water for survival.
Discuss the concept of the "food chain". Follow up this study by collecting pictures of native animals. Collect smaller pictures of plants, insects, and other animals and create a display of how the food chain works for a specific animal.
Create mobiles of food chains for various species. This activity can be done independently or with a small group. Cut plants and animals from magazines and post on cardboard or the students may do original artwork. Each mobile must follow a food chain for a single animal.
Use pictures (animals, reptiles, fish, birds) to introduce wildlife specific to the area. Groups of students are to select two animals to investigate and tell about:
1. The survival rate of each animal.
2. What may have contributed to this animal's success or failure.
Each group may presents their findings to the class by means of skits, debates, discussions, puppet shows, or reports.
Freshwater Fishes, Lawrence M. Page & Brooks M. Burr, Houghton Mifflin Company, Boston MA 1991.
1980 National Wildlife Week, March 16-22. 1980, Published by National Wildlife Federation, 1412 16th St. N.W. Washington D.C. 20036.
Mojave Desert Discovery, (teachers guide) National Park Service, 1994.
Our Living Desert, Las Vegas Review-Journal Newspaper in Education. Las Vegas, NV 702-383-0470.
1996 Arizona Fishing Regulation, Produced by the AZ Game and Fish Department Information and Education Division. 602-942-3000.
Lake Mead National Recreation Area, National Park Service, U.S. Dept. of the Interior, Fishing Information. 702-293-8900.