The
Amateur Herpetologists Guided Field Journal for
Lizards
In
Terry Legg
Final Project
Bi 410
Personal Information
1.
Name
_________________________________________
2.
Age
___________________________________________
3.
Year in
School __________________________________
4.
Lizard
Species of Interest ________________________
_______________________________________________
5.
First
Lizard Memory ____________________________
__________________________________________________
___________________________________________________
__________________________________________________________
Welcome to
the Amateur Herpetologist’s Guided Field
Journal for Lizards in
This guided field journal will hopefully provide you with…
ü
An
introduction to herpetology
ü
Background
information on lizards, the suborder Sauria
ü
A
description of lizard species found in
ü
Preparation
for field investigation
ü
Description
of field techniques
ü
Guided
field exercises
And…
ü
An
exciting introduction to the world of lizards!
Remember to always…
ü
Practice
“catch and release”!
ü
Record
all observations
ü
After
catching lizards keep them in a cool place until release
And…
ü
Have fun!
Table of Contents
Section 1: “The Importance of a Field Journal” p. 5
Section 2: “Terms and Definitions: Scientific Vocabulary Decoded” p.6
Section 3: “Lizards: The coolest little “reptiles” in the world!” p. 7
Section 4: “What’s so special about lizards? General Information” p. 10
Section
5: “So, why are lizards so cool?” p.16
Section
6: “Lizards of
Section
7: “What are you waiting for? Let’s go catch Lizards?” p. 24
Section
8: Field Worksheet p. 25
Section
9: Bibliography p. 28
The Importance of A Field Journal
When studying in “the field” it is necessary to create a field journal. In field journals you write down all observations that you make in the field. These observations can be about the specific subject you are studying, or they can be about the weather, the field site location, other animals and plants you see, or any thoughts and feelings you have throughout the day.
Field journals
are important resources for any scientist because they serve as a record of
your work. You can look back at your
field journal later and get ideas for different types of field study based on
what you have already done. Your field
journal is also important resource for other scientists. For example, say that on
You may be
thinking to yourself, “There is no way that is going to happen to me. I’m not going to discover a new
species!” However the species that are
already identified and classified may only represent a small fraction of true
biological diversity that exists. A
biodiversity inventory project in the
Terms and Definitions: Scientific Vocabulary Decoded
Many people are turned off by science because they think it is too hard to understand. It isn’t that science is especially difficult it just has a different set vocabulary that helps describe phenomena that don’t have proper words in the everyday English language. The following list of terms and definitions will give you a headstart on decoding some scientific vocabulary used in biology and herpetology. Throughout the text of this guided field journal, all of the words used that are defined in this section will be highlighted in bold.
1. Amphisbaen: a wormlike lizard, also called a worm lizard,
belonging to the family Amphisbaenidae
(120 species) occurring in tropical and subtropical
--The Macmillan Encyclopedia 2001, Market House Books Ltd 2000
2. Biodiversity: The number and variety of living organisms;
diversity within a species, species diversity, and ecosystem diversity.
3. Carnivorous: Describes an organism that eats animals.
4. Cladogram: A branching diagram that illustrates taxonomic relationships.
5. Cloaca: an organ that processes food and waste products in lizards.
6. Ectotherm: An animal whose temperature fluctuates with that of the environment; an ectotherm may use behavioral adaptations to regulate temperature; sometimes referred to as cold-blooded.
7. Endotherm: An animal that uses metabolic energy, such to maintain a constant body temperature despite environmental temperature.
8. Eukaryote: Organism whose cells possess nuclei and other membrane-bound organelles.
9. Habitat: The natural environment of place where an organism, population, or species lives.
10. Mammals: Class of vertebrates characterized by hair, mammary glands (milk producing glands), a diaphragm and a differentiation of teeth.
11. Morphology: The structures and form of an organism, including its bone structure, body size, skin characteristics, etc.
12. Omnivorous: Describes an organism that eats a variety of things including animals, plants, insects, detritus, carrion, etc.
13. Phylogeny: The complete evolutionary history of a group of organisms.
14. Prokaryote: A cell that lacks a nucleus and other membrane- bound organelles; includes bacteria.
15. Taxonomy: The science of naming, describing and
16. Temperate
17. Thermoregulation
Lizards: The coolest little “reptiles” in
the world!
As you probably already know,
lizards are part of a larger group of animals commonly called reptiles. Other reptiles include turtles, alligators,
crocodiles and snakes. All these animals
are in a scientific classification group called the Class Reptilia. The scientific classification system is set up to
understand the way organisms are related to one another. Therefore all of the animals in the Class Reptilia share certain common
characteristics.
Within
the Class Reptilia, some animals are
more closely related than others. Lizards
are most closely related to snakes, and are members of the Order Squamata along
with snakes and amphisbaens. It might be easier to understand the
relationships between lizards and other reptiles by looking at a family tree,
also called a phylogenetic
tree, or a cladogram.
In a cladogram, relationships are represented by how close one group is to another on the tree. For example of the animal groups represented in the cladogram amphibians are the most related to turtles and the least related to tuatara, snakes and lizards.
“Beasts of a Feather?” According
to an article published in July of 2000 scientists found a fossil of an
ancient lizard called Longisquama that grew long,
feather-like scales from muscles in its back. This fossil was probably lived 75 million
years before the first known bird, and before most of the dinosaurs. This new finding begs the question again
of which lineage birds evolved from.
Did they evolve from ancient lizards? From dinosaurs? Who knows! And the debate continues… (Petit
2000)
As you can see even though the term “reptile” includes only
turtles, alligators, crocodiles, tuatara, snakes and lizards, non- reptiles
such as mammals and birds are more closely related to alligators, snakes and
lizards than turtles
are. Therefore the group we call “reptiles” may not be so
related after all. One way to adjust for this would be to
include mammals and birds in the general category of reptiles.
This mis-organization of animal groups is mostly due to
changes in genetic technology. Recent discoveries in genetics
have helped to reorganize phylogenetics in a way that presents us with a much clearer picture of relationships between organisms.
Although some reptile groups are somewhat mistakenly thrown together, many reptiles do share a few general 1) physiological, 2) morphological, 3) behavioral and 4) life history characteristics. The following are examples from each of the four categories of characteristics reptiles share.
1) Physiological
All reptiles are ectothermic, meaning that they rely on the environment for maintaining a preferred body temperature. In contrast to endotherms like mammals ectotherms must spend a large portion of their lives maintaining their body temperature, also called thermoregulation. Since humans are endotherms when we are very hot our body reacts to cool us off by perspiring. Reptiles have no such physiological system that maintains an optimal body temperature.
2) Morphological Reptiles have dry, scaley skin. Unlike amphibians reptile skin is very thick, and doesn’t require hydration. Also, if you’ve ever touched a reptile’s skin you know that it usually feels smooth if you stroke it from head to tail, but rough in the other direction. That is because of the direction in which the scales lie on the skin top layer of skin.
Another thing you would have learned from touching reptile skin is that it is hairless. This is another feature that separates reptiles from other animal relatives such as mammals.
3) Behavioral
As ectotherms reptiles often control their body temperature using behavioral techniques. Although these behaviors vary between reptile species, there are some general behaviors that most reptiles use to thermoregulate. For example when outside temperatures are very warm reptiles often hide under a rock or a shady place so that their body temperature does not become so high that it is fatal.
4)
Life History
Contrary to popular belief not all reptiles lay eggs. However most reptiles do practice internal fertilization whereby a female’s eggs are fertilized by a male’s sperm inside her body. Internal fertilization and reproduction will be explained further in the next section.
When studying lizards it is important to think about how they are related to other reptiles as well as organisms in other animal Classes. As you follow along in this field journal remember these shared general characteristics of reptiles and look for examples of species that do things a little differently. To be a smart scientist you must always question generalizations and look for the exceptions!
What’s so special about
lizards?
General Information on the
suborder Sauria
So you thought you could forget about the Scientific Classification system? Not so, my friend. In order to understand lizards you must understand the way they are organized into Classification categories. As reviewed in the previous section lizards are in the Class Reptilia, and they are in the Order Squamata with snakes and amphisbaens. Squamata is the most diverse of four living orders of reptiles, containing 96% of known species (Brodie, Jr., Nussbaum, Storm 1983). The Order Squamata is further divided into two Suborders, Serpentes and Sauria. The Suborder Sauria represents all of the lizard Families, including Anguidae, Iguanidae, Scincidae, and Teiidae. Each of those families is further organized into families and species. There are over 2,300 lizard species known and classified in the world (Brodie, Jr., Nussbaum, Storm 1983). Specific characteristics about these families, genus and species will be discussed in the Section 6, “Lizards of Oregon.”
This section serves as a basic “crash course” in lizard ecology. In order to actually find and catch lizards in the field, you will need to understand the fundamental aspects of life as a lizard. Understanding these fundamentals will help you make sense of why lizards are grouped together in one Suborder. Hopefully this information will also explain how their shared morphological, physiological, behavioral and lifestyle characteristics differentiate lizards from other reptiles. Of course not all lizard species have the same physical or lifestyle characteristics, but they do also share many things in common.
“A body built to size”: Lizard Morphology
“New Lizard
Ties for ‘world’s smallest’” In
December of 2001 scientists S. Blair Hedges and Richard Thomas discovered
the smallest lizard in existence.
This lizard in only 16 millimeters long from the tip of its nose to
the tip of its tail! The new species,
called Sphaerodactylus arisae
lives in moist leaf litter in the This
species has other fascinating characteristics in addition to its miniature
size. Female S. arisae only lay
one egg at a time, and each egg is almost the size of the mother’s
body! This huge egg hatches to
release a baby lizard that is no less than ¾ of the size of an adult. Maybe size doesn’t explain everything! (Milius 2001)
You are
already familiar with a lizard’s basic body shape and design. Most all lizards have an elongated body, four
well- developed limbs, a sprawling gait, relatively short bodies (compared with
snakes), a head and a tail. Lizard
bodies are covered with scales that vary in size and shape between species. All of the lizard species in the Northwest
are about the length of an adult human hand or smaller, roughly ranging snout
to vent length (tip of the nose to the end of the body, not including the tail)
from 54 mm to 140 mm long. Lizard size
is measured excluding tail length because tails can break off, fall of or be
eaten off!
Small lizard size is a benefit for species in
the
Basin and Southwest desert region. Small objects
have a high surface area-mass ratio, which means
that the surface area of their body is proportionally
greater than their relative mass. This, in addition to
the elongated shape of their body increases rates of heat loss. In a hot desert climate this is definitely an advantage.
“What’s for Dinner?”
Lizards do not all share a specific eating strategy. Lizards can be carnivorous, omnivorous and insectivorous. Lizards’ food choices are very related to their physiology, and their ability to withstand various environmental conditions. Lizards that are carnivorous predators can “sit and wait” for their prey to run by instead or foraging for a large portion of the day like omnivores. Foragers expend much more energy than predators in finding food and their physiology must be designed to withstand a greater energy needs.
“Home, Home on the Range…”: Habitat and
Territory
Lizards are able
to survive in a variety of different habitat types. Lizard species in
Saxiculous habitats are rocky
hillsides, usually located near desert and/or sagebrush steppe
environments. The rocky nature of saxiculous habitats provides plenty of shade and shelter,
but they are also plagued with extreme temperatures, as are the native
sagebrush/juniper and sagebrush/grassland habitats. Advantages of the sagebrush habitats include
that they provide plenty of shade and shelter as well as open, sandy places on
the floor for lizard predators to snatch their dinner. Unfortunately these native habitats are often
altered by cattle ranching. Cattle
prefer non-native grasses such as cheet grass and
crested wheat grass to the native bunch grasses. In contrast to the bunch grasses that allow
for open areas on the grassland floor, the non-native grasses planted in
Oak savanna habitats and forest habitats are
generally located in areas with milder daily and seasonal temperature
fluctuations. Forested habitats in
A majority of the lizard species found in
“A Day in the Life of a Lizard”
A lizard’s daily activity is largely dependent on temperature. Temperature, especially in desert- type environments can vary dramatically and therefore a lizard’s activities can vary throughout a day and even hourly. In general a lizard spends its time in a given day looking for food, eating, protecting itself from predators, and regulating its body temperature. In desert environments lizards usually spend the morning and evening hours out and about, finding food and warming themselves. During the warmest and coolest parts of the day lizards find a sheltered environment to avoid dangerous body temperature levels and predation by other animals.
“A year in the life of a lizard”
Lizards also change their behavior throughout the year depending on the climate conditions of a particular season. In warmer months of the year a lizard’s activity is that of the daily activity explained in the previous paragraph. During the cooler months lizards retreat into a hibernation- like state, although they do not technically go into hibernation. Lizards are able to exist when their body temperatures are low and they have very low levels of activity. Unlike humans their body temperatures are not maintained at a constant temperature. This allows them to survive throughout the entire year, even during periods of cool temperatures with almost no energy requirements or energy expenditure.
“Loco Locomotion”
Lizards have four limbs and in general they use all of
their limbs for locomotion, or in other words they are quadrapedal. Most lizard species can move quickly using
their four legs, as you will attest to after spending a day in the field chasing
after them. Other lizard species, such
as the Mohave Black-Collared lizard (Crotaphytus bicinctores) are known to travel at great speeds on
only their hind limbs! Scientists in the
“Let’s Talk About Sex, Baby…”
All lizards develop from an egg, although not all lizard species hatch from eggs that have incubated outside the mother’s body for any length of time. Lizard eggs are internally fertilized, meaning that the male inserts his sperm into the female to fertilize the female’s eggs. Mating in lizards can be a sort of performance involving rituals, and behavioral displays. The males are primary actors in this performance and they attempt to attract females by doing head bobs, push- ups, and fighting with other males. Once a mate has been chosen, males usually grab females by the neck skin and insert their hemipene into the female’s cloaca. The female stores the sperm in her body for up to a few weeks until her eggs have grown to the point of being ready for fertilization.
Once the eggs are fertilized females either deposit them
under some sort of shelter or they keep them in their body. The species that lay shelled eggs are called
oviparous, and the species that keep the eggs in their bodies until the young
hatch are called viviparous. In vivipary the eggs have an advantage because the mother
protects the young from infection, bacteria and other organisms that may want
to eat the eggs.
“So, why lizards are so cool?” Comprehension Questions
- Name 3 ways that lizards are different than mammals.
- Possible answers: ectothermic, thermoregulation, no hair, scaley skin
- Explain why you can find more lizards out and about on a warm spring day than on a cold morning in December.
- In your own words, “What is thermoregulation?”
- Guess one reason why some lizards lay eggs and some lizards give birth to live lizards.
- Name two different strategies lizards use to get food. (And no, there is no lizard supermarket)
- Where in the world do Lizards live?
- What is the absolute coolest thing you now know about
lizards?
Lizards of
There are four families in the suborder Sauria, including Anguidae, Iguanidae, Scincidae
and Teiidae. Within
these families there are a total of 11 species found in
Anguids
1.Northern Alligator Lizard, Elgaria coerulea
a.Physical description: Usually 100 mm long from snout to vent with a very long tail. Brown, green-brown or dark brown in color. Dark eye color, brown in general. Dark lines run down the edges of the underside of the lizard.
b.Habitat Description: Humid areas in forest or forest clearings,
even along the
2.Southern Alligator Lizard, Elgaria multicarinata
a.Physical Description: This lizard is large, especially compared to the Northern Alligator Lizard, up to 141mm in snout to vent length. Has yellow eyes, and a gray underside with streaks down the center of. Olive-grey, brown or olive- brown in color. The edge of some of the scales are white. There are dark bands down the back and sides.
*Juveniles of the species are slightly different in appearance because they do not have dark bands down their backs and they are tan in color.
b.Habitat
Description: Oak savanna areas, pine
forests for example the
Iguanids
1.Mohave Black-Collared Lizard, Crotaphytus bicinctores
a.Physical Description: Distinguishing characteristic is the “Black collar” or double black lines seperated by a white line that wraps around the neck. Approximately 109 mm in length(S-V) and females are smaller than males in general. Gay, tan or reddish back with lighter polka dots. Males may have a blue- black or black throat patch.
b.Habitat
Description: Prefers saxiculous habitat, rocky slopes and rock piles in dry
climates. Found in
2.Long-Nosed Leopard Lizard, Gambelia wislezenii
a.Physical Description: The back is covered in dark leopard spots, and the underside is white with gray stripes on the throat. They have large heads and are typically 100-116mm long depending on the sex. Females are larger than males.
b.Habitat Description:
3.Short- Horned Lizard, Phrynosoma douglassi
a.Physical Description: Small lizard, about 66 mm in S-V length, with a round body. The body is edged with pointy scales and there are two enlarged scales or “horns” on the back of its head. Back is spotted and coloration usually matches the color of the habitat floor and surrounding features.
b.Habitat Description: Sagebrush plains, and juniper and pine woodlands near the Cascades. An be found at high elevations, up to 3,200 m. This lizard requires loose and sandy soil for burrowing.
4.Desert
Horned Lizard, Phrynosoma platyrhinos
a.Physical Description: Larger than the Short Horned Lizard, up to 95 mm in S-V length. Also has longer horns than the Short Horned Lizard and has black spots on the belly. These lizards als have a dark spot on either side of the neck. Otherwise they appear similar to the Short Horned Lizard.
b.Habitat Description: Open, flat or gently rolling deserts, or sagebrush habitat with sandy rocky soils are needed.
5.Sagebrush
Lizard, Sceloporus graciosus
a.Physical Description: Smaller than related species, only 60 mm S-V length with a long tail. Smaller, less spiney scales than the Western Fence Lizard. Males have blue patches under the throat and on the sides. Females have orange markings on their sides during pregnancy.
b.Habitat Description: Sagebush plains, open juniper and pine forests in elevations of up to 1,700m.
6.Western Fence Lizard, Sceloporus occidentalis
a.Physical Description: Large, spiny scales with a gray or brown back. Grow up to 88 mm in S-V length with very long tails, about 1 ½ times the length of its body. Grayish white belly with blue side and throat patches. Looks very similar to a Sagebrush Lizard but larger in size an dmore pronounced blue patches.
b.Habitat Description: Variety of habitats including foothill areas of the Coast and Cascade Ranges, logged forest areas, clearings, rocky canyons and rocky slopes of deserts and wooded areas. Not found in humid forests or flat desert valleys.
7.Side-Blotched Lizard, Uta stansburiana
a.Physical Description: The smallest lizards in
b.Habitat Description: Desert flats with sandy and gravely soil, rocky canyons and juniper/sage environments. They prefer open areas with no or few trees, and they are only found in elevations up to 1,825 m.
Scinidae
1.Western
Skink, Eumeces skiltonianus
a.Physical Description: Small to medium sized lizards that grow up to 76 mm in length. The back coloration is striped from head to base of the tail with a wide stripe down the center of the back and contrasting lighter and darker stripes on the sides. In juveniles and younger animals the tail is a striking blue color, and the older adults have more of gray- colored tails.
b.Habitat Description: Grassy hills, oak savanna, dryer coniferous
forests, rocky canyons and pine/juniper woodlands. Also found at elevations of 1, 525 on
Teiids
1.Western
Whiptail, Cnemidophorus tigris
a.Physical Description: Dark gray and brown in color with 4 stripes going down its bach from head to tail base. These stripes are seperated by spotted pattern. The tail is long and uniform in color. The back coloration looks like a seersucker pattern. The underside is also patterned. They can grow up to about 112 mm in S-V length and their tail can grow to a couple of hundred centimeters.
b.Habitat Description: Desert areas with dense, sagebrush-type vegetation, sandy areas and rocky areas. Loose soils with rodent burrows are charactersitic of Western Whiptail Habitat.
“What are you waiting for? Lets go catch so lizards!”
Hold on there. You need to know a few more things before you hit the trail. You need to know..
ü Best times of day to find lizards
ü Times when temperature is the least extreme, for example early evening and late morning.
ü How to “Noose ‘em”
ü Get a fishing pole or another type of long pole and tie a dental floss slip loop on the end. Move very slowly when you see a lizard and try to slip the noose over its head. Gently pull up once it is around the neck. When done correctly this does not hurt the lizard.
ü Other materials
ü Cotton bag, pillow case
ü Small cooler, especially if it’s a very hot day
ü Notebook, pen/pencil
ü Hat, sunscreen, water(!!!)
ü A lizard hunting buddy
ü
Your handy-dandy “The Amateur Herpetologist’s
guided field journal for Lizards in
In the Field: Notes, Drawings, Observations and Deep Thoughts
(This section of the field journal will be a number of duplicated worksheets students can fill in while in the field. The following is one example of this worksheet.)
*While you are in the field remember to record all observations, about the time, location and habitat in which you found each lizard. Feel free to also include any other thoughts and descriptions of the day, especially anything you see for the first time.
Observed Individual 1
Date:
Time:
Location:
Habitat Description:
Soil:
Plants:
Rocks:
Other Animals:
Other distinguishing characteristics:
Approximate Temperature:
Weather:
Catch technique (hand, noose):
Time spent catching individual:
Other Observations:
What does the Lizard look like?
Sketch:
Distinguishing body markings:
Coloration:
Locomotion: While chasing it, did the lizard run on hind legs, on 4 legs, was there anything interesting about the rate at which it moved or way in which it moved?
Movement/Activity: Is the lizard playing dead or squirming? Did it bite you? Is it acting hostile or docile?
Identification: Guesstimate the genus & species
Why did you guess this species?
What distinguished this individual from others you have observed?
Do you think it is a juvenile or an adult? Female or male? Why?
*Now check your guess against the identification key in Section 8.
Follow-up questions for observed individual 1:
- Did your species guesstimation fit the identification key?
- Was the lizard easy or hard to catch?
- Describe strategy
- Guess some reasons why this individual might have been easy/hard to catch.
i. For example, body shape, size, etc.
- Is this individual share similar characteristics with any other species you have seen/learned about?
- Does the time of day at which you found the lizard tell you anything about its behavioral characteristics?
- What type of predator do you think this species is? Why?
*you can refer to the species description guide if you like.
- What is the most interesting feature of this lizard, in your opinion? Why?
- Any other Thoughts?
Section 11: Scorecard
To keep track of your catches in the field, tally the individuals you observed here.
Northern Alligator Lizard (Elgaria coerulea):
Southern Alligator Lizard (Elgaria multicarinata):
Mohave Black-Collared Lizard (Crotaphytus bicinctores):
Long-Nosed Leopard Lizard (Gambelia wislizenii):
Short Horned Lizard (Phrynosoma douglassii):
Desert Horned Lizard (Phrynosoma platyrhinos):
Sagebrush Lizard (Sceloporus graciosus):
Western Fence Lizard (Sceloporus occidentalis):
Side-blotched Lizard (Uta stansburiana):
Western Skink (Eumeces skiltonianus):
Western Whiptail (Cnemidophorus tigris):
Plateau Striped Whiptail (Cnemidophorus velox):
Literature Resources
Adams, Mark and Sharon Downes. 2001. Geographic Variation in Antisnake Tactics: The Evolution of Scent Mediated Behavior in a Lizard. Evolution 55:605-614.
Benabib, Miriam, Karl M. Kjer and Jack W Sites, Jr. 1997. Mitochondrial DNA Sequence-based Phylogeny and the Evolution of Viviparity in the Sceloporus scalaris Group (Reptilia, Squamata). Evolution 51:1262-1275.
Bissel, Ahrash
N. 2001.
Population Differences and Behavior of Lizards: On the Road to Speciation? PhD Dissertation for the
Biology Department at
Brodie, Edmund D Jr., Ronald Nussbaum and Robert Strom. 1983.
Amphibians and Reptiles of the
Brown, H.A., R.B. Bury, D.M. Darda,
L.V. Diller, C.R. Peterson, and R.M. Storm. 1995.
Reptiles of
Downes, Sharon. 2001. Trading Heat and Food for Safety: Costs of Predator Avoidance in a Lizard. Ecology 82:2870-2882.
Gibbs, W. 2001. On the Termination of Species. Scientific American 285: 40-49.
Greenberg, Neil and Paul D. MacLean. 1978.
Behavior and Neurology of Lizards.
Huey, Raymond B. and Eric R. Pianka. 2001. How Often do Lizards Run on Empty? Ecology 82:1-6.
Huey, Raymond B., Eric R. Pianka and Thomas W. Schoener. 1983.
Lizard Ecology: Studies of a
Model Organism.
Milius, S. 2001. Reports on Discovery of Smallest Lizard in the World: New Lizard Ties for World’s Smallest. Science News 160:356
Petit, Charles. 2000.
Beasts of a Feather?
Summers, Adam. 2001. Sand Dune Two-Step. Natural History 110:90-92.