TEACHER'S GUIDE TO CRYPTIC CLUES: THE WETLAND CLASSROOM
PURPOSE:
The learner is first asked to list the wetland plants and/or animals with which she or he is familiar. The
purpose is to encourage students to remember previous experiences of wet ecosystems as an entry
into the present exercise. After setting the stage, the Cryptic Clues Exercise provides descriptions of
various kinds of organisms that inhabit our wetlands.
INTENDED GRADE LEVEL:
Recommended for grades six through nine.
LEARNING OBJECTIVES:
Note to teachers:
Searching for "clues" is an exciting adventure for students and an excellent
motivational teaching method. It not only challenges the students to "look" but also
promotes a heightened sense of awareness and allows them to focus on details.
Important objectives for developing such an activity would be to place priority on
higher thinking skills – challenging the students to process the information and
assess adaptations and interrelationships within a wetland habitat.
1.
Students will identify fragments or evidence of the plants and animals living in wetlands from the
drawings provided.
2.
Students will use reference texts such as field guides to identify fragments or evidence of the
plants and animals living in wetlands.
3.
Students will list and describe specific ecological principles related to wetland animals and plants.
METHODS/MATERIALS:
Potentially new vocabulary words are found in italics, followed by a simple definition at the end of the
text. The student can identify a limited group of plants and animals using this exercise sheet. This is
done by comparing the drawings provided with what is found in the wetland. Further identifications will
require reference texts, such as those listed in the "Additional Resources" section of the Cryptic Clues
Exercise.
-1-
CRYPTIC CLUES: THE WETLAND
CLASSROOM
Setting the Stage
Venturing into a wetland is an experience of great surprises. The wide-eyed student is a
"Sherlock Holmes," sleuthing the swamps…a detective of boggy denizens.
The students should take a moment to imagine they are standing in a Pennsylvania marsh.
Visualize the plants and animals that might be there and listen to the sounds of the marsh.
Sometimes plants and animals are observed directly, and can be identified by the observer. At
other times, plants and animals leave more cryptic clues behind to be identified. This exercise
will help learners determine the identity of clues found in wetlands. Amazing stories of wetlands
may be waiting for those aware and attuned to the clues that surround them.
There are many kinds of animals, trees, shrubs and herbaceous plants that occur in wetlands.
Try to list on a board or chart paper any plants or animals that might live in a swamp, marsh,
bog, fen, or shallow pond.
Cryptic Clues: Animals. The following are some clues used to identify wetland inhabitants.
Remember, unless instructed, all plants and animals should not be disturbed or removed from
their habitat.
1.
Bird nests. Many birds utilize wetland plants to build their nests. Often, bird nests from the
previous breeding season are evident. Wetland birds include red-wing blackbirds, sedge
wrens, and numerous species of shore and wading birds and waterfowl. (See "Values of
Wetland Plants to Wildlife" (3930-BK-DEP3083) for a listing of birds.) The northern
waterthrush builds its nest in upturned roots of fallen trees in wooded swamps. Loons,
Canada geese and others build directly on the ground, as close to water as possible, while
green herons and many other birds construct a platform of sticks near or overhanging
water, often in trees. Frequently, a muskrat house will be used by birds for a solid
foundation on which to construct their nests. Hollow tops of stumps, and holes or cavities
in snagwood also offer nesting possibilities. There are many field guides to help name the
birds that build the nests that are found here. During breeding season, eggs found in the
nests can help identify the occupants. Identify any nests or eggs seen in the wetland. Use
books that show pictures of birds' nests or eggs. It is important to avoid disturbing eggs
and nests. Care must be taken to protect nests, eggs, and nesting birds.
-2-
2.
Eggs. In addition to eggs from birds' nests, eggs of other animals such as frogs, toads,
snakes, or turtles can be observed in wetlands. Gelatinous masses of eggs are deposited
by amphibians in the water, or sometimes laid singularly, attached to submerged aquatic
vegetation. Turtle eggs are buried in the sand or mud along the shore, in large groups
called clutches. The leathery eggshells can be seen after hatching or the remains found
after the eggs have been discovered by hungry mammals that devour their contents! Have
you seen any of these?
CANADA GOOSE
GREEN
HERON
3-2/5"
EGGS:
 unmarked to nest-stained
 4-10/nest (aver. 5-6)
 smooth, not glossy
NEST:
On ground, near water, on
stumps, mounds, muskrat nests
Eggs: greenish to
bluish green
Nest:
a platform
of sticks
TOAD
EGGS
HATCHLING
(Laid in strings)
TOAD
TADPOLE
24 to 40 round, hard-shelled eggs of
SNAPPING TURTLE
in underground nest
3.
Snake Skins. Snakes periodically shed their skin and leave the "clothing" behind.
Several species of snakes thrive in wetlands. A well-known, common snake that can be
found in wetlands is the garter snake. Garter snakes have three yellowish stripes on a
dark mottled background. Litters consist of 14 to 40 young born alive. Northern water
snakes, displaying a large array of variation, also make a living in wet habitats. The
northern water snake bears dark blotches on its sides and back. It often has dark, halfmoon markings on the belly scales. Water snakes feed on slow-swimming non-game
fish. They will bite, but are not venomous. Here are some snake scale patterns to look
for when you find a shedded snakeskin:
-3-
NON-POISONOUS SNAKE
POISONOUS SNAKE
WITH RATTLE
-HEAD-
-HEAD-TAIL-


WITHOUT RATTLE
TUBULAR
ROUNDED
-TAILS-
 TRIANGULAR
 FLATTENED
*Note: Always cautiously observe snakes from a safe distance. Do not attempt to
capture or tease snakes. Only qualified persons should handle snakes found in
Pennsylvania. Pennsylvania has three venomous species of snakes: copperheads,
timber rattlers, and massasaugas. Copperheads are common but seldom encountered
since they are nocturnal. They occur south of the glacial boundary in Pennsylvania.
Rattlesnakes are found in mountainous regions of the state. The massasauga is an
endangered species in Pennsylvania.
4.
Pellets (castings). Birds of prey (e.g. owls and hawks), ravens and shrikes “cough up” or
regurgitate undigested animal parts, such as hair and bones, in the form of “pellets.” Can
you find any pellets, also called castings, left behind by a wetland visitor? Why might the
birds of prey come to the marsh? Identify the contents of the pellets. Some castings look
like this:
PELLETS
(CASTINGS)
FEATHERS
FUR
OWL
2”
RED TAIL HAWK
2-3/4"
-4-
OWL
1"
SPARROW HAWK
1-1/4"
SHRIKE
5.
Browsing. Evidence of animal browsing (herbivore) and chewing may be seen in a
wetland. As upland areas are developed, deer, bear and other animals spend more time in
wetlands. They travel to wet habitats for natural shelter and food. Can you find bare twigs
or partially eaten leaves? What might have eaten them? Make a list of the plants that show
evidence of having been browsed. Can you note the angle of the teeth? Describe the
location of the browse from ground level. Does the height from the ground help you
identify the herbivore?
6.
Droppings (scat). Examination of animal droppings is a valuable means of learning about
animals (and indirectly plants) in wetlands. Deer, snakes, geese, ducks, muskrats, otters,
beavers, rabbits, and foxes, to name only a few, leave their waste behind. Look for berries,
seeds, fur, hair, and bones. Can you determine which animals are herbivores, carnivores
and omnivores? Droppings can give us information about the size, distribution and
composition of animal populations. Fecal matter can sometimes be used to reveal the size
of the animal, group behavior (individual or herds), amount of time spent in an area and
nature of feeding habits (herbivore, carnivore or omnivore). Be careful to handle feces with
disposable laboratory gloves, and clean your hands after handling.
SCAT
TOAD
¼"
MINK
3/8" dia
FROG
(varied sizes)
MUSKRAT
½"
VOLE
5/32"
BEAVER
1-1/4"
DEER
1-5/8"
3-1/2"
GOOSE
(CANADA)
-5-
CHIPMUNK
lf
OPOSSUM
1-5/8"
lr
WHITETAIL DEER
lf
2"
2-3/4"
lr
7.
Tracks and Signs. Many animals, such as muskrats, inhabit wetlands. Others like
opossums and raccoons, although not dependent upon wetlands, frequently visit them.
Tracks (paw or foot prints) and signs (body motion prints) are found in abundance. In the
summer, they are seen in mud or wet sand, while in the winter they are left in the snow.
They differ significantly in their pattern when the animal is walking, running, or bounding.
Tracks and signs are often diagnostic for the animals that produce them. Several excellent
field guides can be used to identify the animals that leave telltale marks behind. These
books often include ways to identify droppings and bird pellets as well. Some are listed at
the end of this activity. Readily recognized tracks include those of opossum, bear, vole,
raccoon, deer, otter, muskrat, many waterfowl, and shorebirds. Can you find any of these?
(lf = left front; lr = left rear)
lf
5-1/4"
2-1/2"
lr
BEAVER
STRIPED SKUNK
-6-
2"
MARTEN
GREAT BLUE HERON
TOAD
WALKING
MALLARD
DUCK
4"
TRACKS OF
EARTHWORMS
IN WET MUD
GARTER SNAKE
FROG
(size varies with species)
HOPPING
-7-
Often, tracks of turtles and signs of crawfish also are discernible. They look like this:
CRAYFISH BURROW
UNDER WATER
(2 entrances)
SNAPPING TURTLE
RIVER OTTER
RACCOON
3"
MEADOW VOLE
BOUNDING
lf
lf
lr
4"
MINK
1"
lr
1-3/8"
Signs of animal activity include meadow vole “runways” cut in the thickly matted grass of soggy
ground. These “runways” disappear into holes where the animals nest. Shrews and deer mice
use the “runways” of meadow voles. Therefore, fecal droppings from several species, as well as
clippings of wetlands plants, can be found in them.
Beaver lodges and muskrat mounds disclose the presence of these animals. However, it should
be remembered that not all animals are so obvious as the ones mentioned above. For example,
-8-
the water shrew, though living very close to water as the name implies, leaves few
distinguishing signs behind.
In winter, you may discover a smooth, round tunnel through the snow leading to an “airhole” in
the ice of a river. These are mink architecture that tell us the animal has been searching
underwater for dinner. If the hole is somewhat “muddy,” the mink has been foraging on the river
bottom for frogs or other food.
When we ask the right questions, trails and signs reveal many things including territorial
boundaries. They can tell us a lot about the interactions among members of the same species,
as well as about the dynamics between different kinds of animals.
-9-
Cryptic Clues: Plants. The following are some clues useful in identifying plants from wetlands.
Remember, unless instructed by the appropriate person, leave plants or plant fragments in the
wetlands.
PIN OAK
BASKET OAK
SWAMP WHITE OAK
RED ASH
LEAFLET
TWIGS
WITH LEAF
Buds
STALK SCARS
FRUITS
of
RED ASH
BLACK ASH
Scar
ASH
TWIG
- 10 -
FRUIT
BUD
leaf
stalk
TWIG
Note: hollow leaf
stalk
SYCAMORE
CUT
FRUIT
FRUIT
LEAF
LEAF
(cut to show
rolled edges)
CASSANDRA
BOG ROSEMARY
- 11 -
FRUITS
NOTE:
OPPOSITE
LEAVES
RED MAPLE
LEAF
TWIG
FRUITS
FLOWER
BUD
LEAF
BUD
LEAF STALK
SCAR
BUD
FRUITS
ALDER
SPICEBUSH
TWIG
TWIG
FRUIT
(HIP)
WINTER
BERRY
SWAMP ROSE
- 12 -
FLOWER
BUD
ARROWHEAD
TWIG
DRIED
CAPSULES
FLOWER
LEAF
Soil Line
CATTAIL
SKUNK CABBAGE
FLOWER APPEARS IN LATE WINTER;
LEAVES IN SPRING
- 13 -
OLD
FLOWERS
AND
CAPSULES
SPIRAEA
FERTILE
FROND
RATTLE
BOX
STERILE
FROND
SENSITIVE
FERN
SPIKE
RUSH
BUR
RUSH
BULL RUSH
- 14 -
GLOSSARY OF TERMS
Amphibian
An animal such as a frog, toad or salamander that spends part of its life in
water, the other portion on dry land
Birds of Prey
Birds that primarily obtain food by the killing and consuming of other animals
Bogs
A wetland, usually with blocked drainage of acidic conditions, where cushion
plants and peat moss (sphagnum) dominate
Carnivore
Feeding behavior associated with flesh-eating; subsisting on animal tissue
Clutch
A nest or group of eggs
Fecal
Waste or excrement
Fen
A marsh
Gelatinous
Covered with a slimy substance; slippery or quivering when handled
Habitat
The location or site where a plant or animal usually lives and grows
Herbaceous
Plants that are soft-bodied, having little or no woody tissue and generally living
only one growing season
Herbivore
Feeding behavior associated with plant-eating; subsisting on vegetative tissue
Loon
A fish-eating, diving bird
Marsh
A wetland where the dominant plants are herbaceous, such as reeds, cattails,
rushes, grasses and sedges
Omnivore
Feeding behavior associated with eating both animal and plant substances
Pellets
Incompletely digested food that is cast up from the digestive system of animals
Population
A group of interbreeding plants or animals of the same species (type)
Regurgitate
To throw up; cough up
Shallow Pond
Wetland areas of small acreage, where the water is usually less than 2 meters
(6.6 feet), and the water temperature is uniform from surface to bottom
Shrew
A mole-like animal with a long pointed snout, small eyes, ears and soft fur
Scat
animal waste (excrement); droppings
Snag Wood
Dead trees; usually a tall trunk with a few remaining limbs attached; valuable
habitat for animals
Submerged
Aquatic Vegetation
Those plants that live and grow completely underwater or just up to the water
surface
Swamp
A wooded wetland where the dominant vegetation is trees and/or shrubs
- 15 -
Variation
The difference in appearance or characteristics of a plant or animal from those
typical to its group; important in the evolution of a species because survival
rests on individuals best adapted to changing conditions
Vole
Mole-like animal with a blunt snout and short ears
- 16 -
Quiz for Cryptic Clues: The Wetland Classroom
A.
B.
C.
D.
E.
F.
- 17 -
I.
H.
G.
K.
J.
L.
M.
All prints have been taken from: Headstrom, Richard. 1971. Identifying Animal Tracks: Mammals, Birds,
and Other Animals of the Eastern United States. New York: Dover Publications, Inc.
- 18 -
Answer Sheet
Quiz for Cryptic Clues: The Wetland Classroom
A.
Raccoon running
B.
Mink walking
C.
White-tailed deer galloping
D.
Heron walking
E.
River Otter running
F.
Duck walking
G.
Opossum walking
H.
Striped Skunk walking
I.
Sensitive Fern Fertile Frond
J.
Red Maple fruit and leaf
K.
Rattle Box, Seed Box (Ludwigia alternifolia)
L.
Ash
M.
Sycamore bud and leaf stalk
- 19 -
Additional Resources
Burt, William Henry and R. P. Grossenheider. 1976. A Field Guide to the Mammals: North
America north of Mexico. Peterson Field Guide Series 5. Boston: Houghton Mifflin Co., 289 p.
Conant, Roger. 1975. A Field Guide to Reptiles and Amphibians of Eastern & Central North
America. Peterson Field Guide Series 12. Boston: Houghton Mifflin Co., 429 p.
Core, Earl, L. and Nelle P. Ammons, 1981. Woody Plants in Winter: A Manual of Common
Trees and Shrubs in Winter in the Northeastern United States and Southeastern Canada.
Pacific Grove, CA: The Boxwood Press, 218 p.
Harlow, William M. 1946. Fruit Key and Twig Key to Trees and Shrubs. New York: Dover
Publications, Inc. 50 p. + 56 p.
Harrison, Hal H. 1975. A Field Guide to Bird’s Nests. Peterson Field Guide Series 21. Boston:
Houghton Mifflin Co., 257 p.
Headstrom, Richard. 1971. Identifying Animal Tracks: Mammals, Birds, and other Animals of the
Eastern United States. NY: Dover Publ., Inc. 141 p.
Knobel, Edward. 1972 Identify Trees and Shrubs by Their Leaves: A Guide to Trees and
Shrubs Native to the Northeast. NY: Dover Publ., Inc., 47 p.
Magee, Dennis W. 1981. Freshwater Wetlands: A Guide to Common Indicator Plants of the
Northeast. Amherst: The University of Massachusetts Press, 245 p.
Murie, Olaus J. 1974. A Field Guide to Animal Tracks. Peterson Field Guide Series 9. Boston:
Houghton Mifflin Co., 375 p.
- 20 -
For more information, visit DEP’s website at www.dep.state.pa.us,
keyword: Watershed Publications.
For more information contact:
Department of Environmental Protection
Bureau of Waterways Engineering and Wetlands
Division of Wetlands, Encroachments and Training
P.O. Box 8460
Harrisburg, PA 17105-8460
717.787.3411
3150-BK-DEP1392
Rev. 9/2015