Part 1: THINK HABITAT (about 1 hour) is conducted outdoors. Activities include walking, storytelling, noticing eco-regions, and looking under logs and coverboards.
Announcement prior to gathering: Insect repellent may be used but participants must wash their hands prior to departing. Repellent could harm the animals. Once the group gathers, introductions are made and the program is described prior to departure. Participants are invited to carry the snake bags or snake hooks.
Let participants know the expectations before embarking on the walk: the group will stay together while walking, everyone will tell a snake story, and everyone should have access to a field guide. Our participants are required to wear name tags and leaders are encouraged to call participants by name.
Participants sharing stories of snake experiences.
- snake bags
- hand wipes
- field guides to local reptiles and amphibians
- a snake hook (rarely used)
- hoes or sturdy rakes to turn coverboards
Everyone has a snake story they want to tell, so we begin our program taking turns telling stories as we walk the grounds checking coverboards. If a participant can’t think of a snake story, suggest they tell about their favorite snake or most-feared snake or a snake fact they find fascinating. Although most of the stories end badly for the snake, the Project Leader listens carefully, shows interest in the individual student, and is nonjudgmental. Storytelling provides a chance for the students to talk, to be heard, and to reveal a little about themselves. Most participants enjoy talking about themselves and learning about others in this way and thus this activity is a great ice-breaker.
Questions you might ask along the way: Why are coverboards attractive for animals? Do you think coverboards in sunshine or shade would be most attractive for snakes? Do you think two different kinds of snakes will use the same coverboard at the same time? What are snakes eating in this area? Do any snakes eat plants? What do you think the ancestors of snakes looked like? What would you call this type of habitat?
This can be done solo, but having a group means we can designate two people as “catchers” and two people as “lifters.” Catchers are agreeable to catching reptiles or amphibians found under the boards. It is not unusual in our areas for all of the coverboards to be checked during summer, when our programs are held, and no snakes found (spring and fall are much better times for finding snakes under these types of cover). Lifters lift the coverboards, preferably using a tool such as a hoe, (reaching across the board to lift the side farthest away so that the animal underneath will not see the lifters. The catchers are ready to spring into action, but stand perfectly still as the board is being lifted. If a lizard or snake is uncovered, the catchers quickly gather it. Even if surprised, the lifters DO NOT drop the coverboard as it could harm the creature below.
Scrape around under the coverboard if leaves and other debris are present. Several animals of different or the same species may be present. Don’t forget to look for animals of all types, especially invertebrates. Try to decide if the invertebrates are herbivores or carnivores. Invertebrates can serve as food for various reptiles. When done looking, gently place the coverboard back on the ground.
Although our programs do not include snake watching outdoors (unless a special opportunity presents itself), you should let participants know that observing snakes from a comfortable distance is a worthwhile and enjoyable activity. One can learn a lot about snakes such as their behaviors, fears, and needs if you watch them long enough, though some stay perfectly still for hours. Observing snakes in nature or in captivity will allow you to begin thinking like a snake and to understand the motivations driving their behaviors. Not frightening the snake is important for both watching and catching. Of course, in order to watch snakes, one needs a suitable place where they are likely to find snakes moving about, basking, feeding, or swimming. Ask your local park ranger about good spots to find wildlife. Roads and platforms overlooking swamps are particularly suitable for this type of activity.
Using binoculars can be a great help, and you can let your birding friends know that binoculars are for more than watching birds! Insects, frogs, turtles, and other herps are exciting subjects too.
Part 2. THINKING LIKE A SNAKE is our indoor activity. This section includes Materials, Preparations, Empathy for Snakes, Snake Biology, Snake Senses, Snake Identification, Handling Guidelines, Shed Skin Study, and Measuring Snakes. Feel free to experiment with the order of these activities.
- 5-7 snakes (non-venomous, local, wild-caught and a few captive bred snakes)
- Cages with covers and DO NOT REMOVE COVER signs on each (where the snakes are kept)
- Snake identification books
- 5-20 shed snake skins, some from venomous species if available
- Hand-made squeeze box, string, and measuring tape or wooden meter stick
- Snake and mammal skulls (if available)
- Models of local venomous snakes (a good source is Morgan Reptile Replicas)
This section includes background material related to the numbers and types of snakes used in our program. We house 18-20 native wild-caught snakes so that 5-7 of them will be available each day for our 5-day program with 5-7 participants per group. Our snakes are caught specifically for this purpose and are released exactly where captured when the sessions are completed. This seems to be a successful strategy since we have caught some of the same snakes in successive years in the same locations.
Please note that caring for wild-caught snakes takes more experience than caring for captive bred snakes. Consult your state zoo or herpetological society for advice and use the considerable online resources that are now available. Sometimes local nature centers do not have someone on staff with the requisite expertise to advise you so seek experienced help.
Why so many snakes?
We house about three times as many snakes as we will use in any one day. The reasons are:
- Our programs are offered every day for five days. Programs offered less often would not need as many snakes.
- As a rule, we don’t handle individual snakes two days in a row. Snakes tire easily and the teaching sessions are more stressful for some species than others. Fatigued snakes are irritable and may strike at cage walls more readily.
- We don’t handle snakes that are in-shed (preparing to shed skin as evidenced by opaque eye coverings), but we use them to show students how to recognize snakes in-shed, sometimes called “in the blue.”
So in our program, it takes about 19-20 snakes to be able to have 6-7 ready for a daily session when programs are held daily. We also use 1-2 captive bred snakes for level-one snakes (see Levels of Engagement). Programs utilizing more captive bred snakes (pet snakes) may be able to house fewer captured snakes.
What kinds of snakes are used?
We want students to become familiar with local snakes so we use small, medium, and large species of non-venomous snakes that are common in our area. For example we use Eastern garter snakes (Thamnophis sirtalis), black racers (Coluber constrictor), black rat snakes (Elpahe [Pantherophis] obsoleta), worm snakes (Carphophis amoenus), brown snakes (Storeria dekayi), mole kingsnakes (Lamporpeltis calligaster), and the like. A high-quality model of the venomous copperhead (Agkistrodon contortrix) is used for identification and comparison with other blotched snakes.
Captive snakes can also be used along with local snakes, but using primarily local wildlife supports our goals of engaging participants with the local fauna, ecology and ecosystems. We use a few long-term captive snakes (captive bred) temporarily loaned by friends of the project or staff members.
Empathy for Snakes
Biology is very important, but to truly understand and appreciate snakes it is important to learn what is important to them, how they manage living successfully, and why it is important for humans to understand them. It is also important to know what scares snakes. Observing snake body language while they are in the cages is an important first step to empathizing with them.
Actively engage participants in every way possible. This student was recording responses to How do snakes respond when they are afraid?
Begin by asking participants what they think the word empathy means and describe what it means to you. Use the sample questions below or come up with others. Ask the question, then give time for responses. Be affirming and positive when students respond (even with wrong answers) and don’t give the correct answers right away. How can you tell when a snake is afraid? or How do snakes respond to threats? These questions are particularly important so make time to discuss this subject in some depth. Have a student write the responses of the participants on board. Let the students call out ideas. Note that no one type of snake will exhibit all the responses mentioned.
Discuss and elaborate as this is one of the best exercises to help students develop empathy for snakes. Answers should include at least all the following: flight, increased respiration, kinking body (muscle contractions), jerking movements, striking, biting, musking, twisting if you are holding them, flattening head, some species hiss and spread neck (e.g. hognose snake), thrashing, dropping from limbs in an attempt to escape, playing dead, coiling, shaking tail, increased alertness, etc. Additional questions related to the same concept are:
Nails on either side of vent in pythons and boas are vestigial structures, which provide support for lots of other evidence that snake ancestors once had legs. Photo by M. Baumeister.
What does it mean when the muscles of the snake tense up? When a snake strikes at a person, what is it trying to accomplish?
Describe some of the other body language of snakes not related to fear. Tongue flicking, ambush position, coiled in hiding, actively moving about.
What is important to a snake? Food, mates, water, privacy, safety, dens or rookeries for some species, ability to control temperature, etc.
Why are snakes important? Are snakes predators or prey? Snakes are important as both prey and as predators. Discuss the food chain and the importance of predators to the health of the ecosystem and to the species that they prey on (population control).
Why are they important to humans? Snakes consume animals that we consider pests and protect our food stores by consuming rodents. Snake venom is very important in the production and development of many medicines. Since snakes are important to their ecosystems they are also important to us – stress that humans are a part of the surrounding ecosystems.
Why is it important for people to understand snakes? Snakes are important elements in the landscape and the biological communities in which they are found. Many, many times snakes are brutally killed because people needlessly fear them or their intentions – mostly out of ignorance or instilled fears. Most children do not naturally fear snakes; it is normally a taught attitude. It can be said that the level of environmental awareness, education and compassion is revealed by one’s attitudes towards snakes.
What is the difference between vertebrates and invertebrates? Which kind of animal is a snake? Vertebrate, reptile.
Which kind of animal are we? Vertebrate, mammal.
What do you think a snake ancestor looked like and behaved like? Just so you know, dinosaurs are not ancestors to snakes. Hint: This type of animal is still around today. Evidence suggests that snake ancestors were a type of burrowing lizard of the early Cretaceous. Snakes lost their legs by growing them more slowly or for a shorter period of time, resulting in shorter and shorter legs, until the legs eventually disappeared. Not having legs gave pre-snakes an advantage in life underground. Those with slower growing legs or shorter legs lived longer and had more offspring (babies) thereby increasing the numbers of leg-less individuals in the population until its legs were lost altogether. However, a few snakes still have remnants of leg bones and nails, like boas and pythons.
Tongue. What do snakes use their tongues for and why are they forked? Have students observe snakes tongue flicking. Show the students the books in the room that have diagrams of the head of the snake.
The tongue is a sensory organ used to sample the air for important information. Air is full of molecules that are invisible to the eye. Tips of tongues grab samples of air. The two tips of the tongue insert air into two openings in the roof of the mouth where an organ is located. Anyone know the name of that organ? It is Jacobson’s organ, which reads scent and sends messages to the brain. The scent molecules in the air may reveal there is food available nearby or water or mates. Neonate rattlesnakes read scent trails to find their way to the wintering den. The tongue is forked to increase the amount of molecules that are received and also to provide a directional component, comparable to our two ears. If the right fork of the tongue grabs air that has a more powerful signal than the left fork, this tells the snake that the source of the scent is to the right and vice versa. Thus the snake may follow a scent without opening its mouth. This allows a stealthy way for snakes to know what is going on in the world without drawing attention to themselves.
Ears. Do snakes have ears? They don’t have external ear openings but are very sensitive to vibration. Serpents evolved from a type of ancestral lizard and lizards have ear openings, but external ear openings may have been a disadvantage for them. Perhaps they were prone to infection from debris entering the openings, so the ancestor burrowing lizards with small ear openings or no ear openings may have lived longer. Living longer allowed them more years to lay clutches of eggs and they produced more offspring, thereby increasing the number of individuals in the population with small ear openings. Over time, snakes lost ear openings altogether. When they emerged from a sub-terrestrial existence and began living above ground, they came up without external ears.
The snake (left) has no ear opening is compared with lizard (right) with ear opening. Photos by Wayne VanDevender
Touch. Snakes are very sensitive to touch. Along with their sense of smell, touch plays a very important role in their ability to survive and respond to threats. Snakes depend heavily on information that comes through their skins and are, at times, able to detect the size of prey and predators based on their vibrations. They are able to feel the slightest changes in their environments and are able to quickly respond to these changes.
Teeth. Preparation: Randomly place skulls on the table. Without explanation ask two students to separate the skulls into those with heterodont dentition and those with homodont dentition. Students can often figure this out themselves and then you can ask them what the words heterodont and homodont mean.
What do snakes eat? All snakes eat meat.
Why are their teeth curved? How would you describe the teeth? Show a snake skull. Mammals, like us, have different kinds of teeth, some sharp, like our incisors, to bite into food, and some flat, like our molars, to grind food. Our teeth are not all the same, and this is called heterodont dentition. Snakes’ teeth are all similar so we would describe snakes as having homodont dentition.
Which animals eat snakes? Who are their predators? Why is predation so important to life? Are you a predator?
How do you tell where the tail of the snake starts? At the vent.
How do you tell if a snake is male or female? It is hard to tell without one of each sex. Look at the first part of the tail, just posterior to the vent; in males the first part of the tail will be thicker and does not taper immediately. In a female the tail will start to taper immediately posterior to the vent. This characteristic is highly variable and the best way to tell is to see snakes mating, because they certainly know which are males and which are females! Another way to tell is by using specialized probes to insert into the cloaca, but we don’t use them and don’t recommend their use as it is very easy to harm a snake unintentionally using probes.
How do snakes reproduce? Do all snakes lay eggs? Many of our local snakes do not lay eggs but are actually livebearers. Live little snakes called neonates emerge from the female’s vent.
What is unusual about a snake’s penis? There are two of them, called hemipenes! Snakes can be identified to species from the morphology of the hemipenes. When mating, male snakes will insert only one into the cloaca of the female. Also see: http://www.sjonhauser.nl/hemipenes-amazing-copulatory-organs-of-snakes.html
How would you describe a snake to someone who had never seen one? Let the students call out ideas. Have a student write responses on the board.
Prior to having students identify snakes, have them look at characteristics of the skin using shed skins. Distribute shed skins among the participants and talk about the shedding process and why snakes shed their skin.
Do we shed our skin? Yes, but not all at once, we are continually shedding skin cells.
If an opaque snake (about to shed) is available, it can be shown to the participants but should not be handled much. Ask students to find a shed skin with strongly keeled scales, one with weakly keeled scales, and one with smooth scales. Keeled scales have ridges, weakly keeled scales have small ridges and smooth scales have no ridges at all.
Are the ventral tail scales divided or not divided? Can this tell you anything about what kind of snake shed this skin? Is the vent scale divided or not divided? How do the dorsal scales differ from the ventral scales?
How often do snakes shed their skins? It depends on how much they are eating and growing. Some fast growing snakes with a good food supply, especially young snakes, may shed several times a year.
Giving each student a shedded snake skin will help them see the difference between the types of scales.
Looking carefully at live snakes. Snake cages are covered when participants enter the room so they won’t become alarmed. Snakes should always be in cages by themselves. Lightweight display cages with clear bottoms (such as deli containers) will enable participants to see the ventral colors and patterns. Once the participants settle down, the covers are removed and students may move quietly around the room.
Participants work alone or in pairs to identify the snakes. Announcement to participants: Working with a partner or by yourself, use a field guide to determine the species of the snake. Focus on the coloration of dorsal (back) and ventral (belly) sides, anterior and posterior, shape of head, rough/keeled or smooth scales, typical species behaviors and the range of occurrence as indicated by the range map in the identification book. It is recommended to have at least three identifying characteristics before confidently stating which species you have.
Using the copperhead model, students are asked to give an elevator speech (a very short and to the point speech given in the amount of time it would take to ascend in an elevator) describing the difference between a copperhead and another blotched snake such as the mole kingsnake.
At least three characteristics are needed to support a species identification in our program. In this case, the participant used the ring around the neck, the ventral coloration, and dorsal coloration to support the identification as a ringneck snake.
Handling Snakes. The absolute best part of the program for all of us and the most fun is getting to handle the snakes. We have developed a system that motivates students to rapidly overcome fears and to try to engage with the various serpents in challenging ways. At the beginning of our program students are asked to use Levels of Engaging with Snakes poster (see below) to identify the level of engagement they are presently comfortable with in regards to snakes. They are then given the opportunity to see others handling snakes and to touch them if they wish, and, without exception, they all touch a snake before the program is over.
It is useful here to emphasize that this experience is much unlike a visit to a nature center where visitors may use two fingers to touch a captive-reared docile snake or possibly even hold one. Our program allows participants to engage with nonvenomous serpents in the way that herpetologists do. They may, if they wish, pick up a snake from the cage or the floor or catch one outdoors.
Video Picking Up a Snake for the First Time:
Video Picking Up a Snake from a Box:
Video Picking Up an Adult Snake from an Aquarium:
They may engage with challenging snakes, ones that are nervous, ones that react suddenly, or ones that may strike or bite. Each person decides if he or she wants to climb the ladder of engagement and has calm, professional support from the Project Leader and/or Assistant Leader.
As the session progresses, students tend to become more and more engaged and seek to climb the ladder of engagement. Each day we have a new group in the snakes unit, but word gets out about the snakes and the engagement levels. By the end of the week-long program, new participants are primed for advancement by the gossip as well as the other programs they have experienced in the HRE where they have become accustomed to handling reptiles and amphibians. On the last 2 days, most of the students reach the highest level of engagement and joyfully proclaim such during lunchtime reports. None of our snakes has ever been harmed in this program, nor has any participant been hurt. Only rarely does a student get bitten, but when they do they are quite proud of the marks left on their skin, if they are lucky enough to have something to show off.
Before you engage participants in this way, please review the information on catching and handling snakes at the beginning of this material.
Ask students to think of three different ways one might measure the length of a snake. (Have a student write these on board) Some possible responses include “stretch the snake”, “let it crawl along a wall”, “put it into a tube”…
A person could try to stretch a snake but, if you do, you could damage the vertebrae because the muscles will tense in response to your stretching. Snakes will squeeze up and loosen up, shortening and lengthening the spinal column, making it impossible to get an accurate reading.
Dead snakes measure considerably longer than live snakes because there are no muscle contractions to compress the spaces between the vertebrae. Snakes have over 200 synovial joints (moveable joints like our knees and backbones) on their skulls and backbones, which is why live snakes can stretch and shrink depending on muscle contractions and dead snakes with no muscle contractions are so much longer than live ones. My 9-year-old neighbor was fascinated by this news and was inspired to say “That must be why snakes are so bendy!” Indeed it is Jack, indeed it is.
Since there really are no good ways to get a single accurate measurement of live snakes, we use a squeeze box because it is the least stressful method we know. A squeeze box is a home-made unit that consists of a piece of foam, a clear piece of Plexiglass the same size as the foam, and a piece of plastic or vinyl that is also the same size.
Above left : Gentle pressure on the plexiglass covering the snake allows the animal to remain calm, safe, and unharmed. Once under the glass, the spine is traced with a dry erase marker then the snake is released. Above right: The line is measured with a string, and the string is then measured with a meter stick.
The video shows how it is assembled and used and why the snakes remain calm, safe, and unharmed.
Video Snake Measuring:
A snake may be in the squeezebox for a minute or less. Simply place the snake between the Plexiglass and the covered foam and gently press down. The snake becomes immobilized without being harmed. Quickly use an erasable pen to draw a line on the Plexiglas from the head of the snake down the vertebral column to the tip of the tail. Then release the snake and return it to the cage. Take yarn or string and trace the line you just created, then measure the length of the yarn or string to get the measurement of the snake. In order to compare snake lengths, one must measure all of the snakes being compared using the same technique.
Venomous and Non-venomous
How can you tell if a snake is venomous by looking at it? (Ask a participant to write all the answers on the board). Some snakes have facial pits near the nostrils. These are the pit vipers. Other snakes, like the coral snake, have heads that look a lot like non-venomous snakes. (Dispelling myths about venomous snake “characteristics”?)
Venomous Copperhead, Agkistrodon contortrix and the non-venomous Northern Watersnake, Nerodia sipedon (right) are often confused.
Anyone know about what percentage of NC snakes are venomous? Of the 37 species of snakes in NC there are only 6 venomous snakes, which is about 16% meaning that 84% of our NC snake species are non-venomous. The six venomous snakes in NC include the Copperhead, Eastern Rattlesnake, Pygmy Rattlesnake, Timber Rattlesnake, Cottonmouth, and the Coral snake.
Do you die if you are bitten by a venomous snake in NC? Venomous snakes may inject some, all, or none of their venom when biting. When no venom is injected it is called a dry bite. It takes a large investment of energy to produce venom so when a snake strikes defensively rather than to acquire food, the venom is sometimes conserved. Most NC venomous snake bites are not fatal but all should be considered serious if any venom at all is injected. A bite from an Eastern Diamondback is an emergency, though the likelihood of encountering one of these snakes is extremely low. Most cottonmouth and copperhead bites are not fatal for humans.
Mole kingsnakes, corn snakes, and juvenile rat snakes are often mistaken for copperheads and killed. Look at coloration, shape of body, and shape of head to identify snakes. A good policy is to just leave them alone and admire and observe them from a distance.