San FranciSco Garter SnakeThamnophis sirtalis tetrataenia

Family ColubridaeGenus ThamnophisSpecies sirtalisSubspecies tetrataenia

Geographic Range Western portion of San Francisco peninsula, along hillsides from San Francisco city line south to Crystal Springs Reservoir and along the coast to Año Nuevo State Nature Reserve.

Habitat Dense vegetation bordering ponds and wetlands with nearby open hillsides

Niche Terrestrial, semi-aquatic, diurnal, carnivorous

Wild Diet Frogs, toads, newts, small fish

Life Span Unknown in the wild, 8 – 15 in captivity

Appearance Body is black with turquoise and red stripes. Weight is between 120 – 190 grams, length is 18 – 51 inches, males are generally half as heavy as females.

Adaptations Female San Francisco garter snakes release pheromones to attract mates. They mate in the spring or fall and females give birth to live young with an average of 16 offspring. These babies are 5 – 7 inches long when born and will mature at two years of age. During dry summer months, when prey is hard to find, San Francisco garter snakes will sometimes aestivate in rodent burrows. When threatened, San Francisco garter snakes will escape into the water or try and defend themselves by releasing a powerful musk with their feces, this makes them smell and taste bad.

To see color photos of this animal, go to www.sfzoo.org/wildaboutartandscience

Fun Facts The San Francisco garter snake was one of the first species to be listed as endangered after the Endangered Species Act was passed. These non-venomous snakes will grab their prey and swallow it whole. They are one of the few animals able to eat the toxic California newt. The San Francisco Zoo is one of the only zoos in the country with San Francisco garter snakes.

At the Zoo Our San Francisco garter snakes live in the Koret Animal Resource Center.

Comparison San Francisco garter snakes have similar defense mechanisms to other kinds of snakes. When threatened, a snake will first try and escape. Depending on the type of snake this could be up a tree, under a rock, into a burrow or in the case of the San Francisco garter snake, into the water. If unable to escape, snakes will then resort to ‘bluffing’ such as a rattlesnake rattling or a cobra raising its hood. Lastly, they will try to retaliate; venomous snakes might strike and non-venomous snakes such as the San Francisco garter snake will emit a foul-smelling substance so that their attacker will release them.

Status and Conservation Endangered

Threats Habitat loss and fragmentation, preyed upon by introduced species, pet trade, decline of food sources, specifically the endangered California red-legged frog

Bibliography Nature Trail Handbook, Animal Diversity Web, Woodland Park Zoo website

Snakes – Amazing AdaptationsMeets 3rd Grade California Science Content Standards – 3a and 3c (see Standards Key)California Visual Art Standard 2.3 - Paint or draw a landscape, seascape, or cityscape that shows the illusion ofspace.Taking It Further - California Visual Art Standard 2.2 - Mix and apply tempera paints to create tints, shades,and neutral colors.

Animal to Draw for Art Contest – A snake

Writing prompt for the sentence of the back of the student’s drawing – Describe one amazingadaptation your snake has and how that adaptation helps it to survive.Objective – To learn some of the amazing adaptations that have allowed snakes to thrive for millionsof years.Time – 20-30 minBackground – Snakes most basic adaptation is the shape of its body. Their lack of arms and legs allowsthem to get into small areas that other predators can’t get into. They have evolved many otheradaptations (some listed below) that have allowed them flourish.Vocabulary –Adaptation – a modification of an animal or plant that makes it more fit to live in its habitat.Jacobson’s Organ – the two small pits on the roof of a snake’s mouth that assist with their sense ofsmell.Quadrate Bone – the bone that connects a snake’s lower jaw to the skull, it acts as a double-jointedhinge to allow the mouth to open extra wide to swallow prey.

List of Adaptations -Can enter narrow holes made by rodentsCan slither through grass or among rocks without causing a disturbanceUnusually flexible jaw with the quadrate bone, enabling them to swallow large preySnakes come in an incredible variety of colors and patterns, some for camouflage to avoid

detection and some are very bright as a warning to other animalsRattlesnakes have rattles on their tail that can be shaken to make a very loud warning soundCommon garter snakes are equipped with glands that exude a very smelly substance when thesnake is disturbedKing snakes have a tolerance towards rattlesnake venom which enables them to kill and eat

rattlesnakesRat snakes can climb up tree trunksGopher snakes can imitate rattlesnakes by flattening their heads and shaking their tail in dry leavesBackward facing teeth to keep food moving in the right direction

Forked tongue to deposit scent molecules into a special section of the nasal cavity called theJacobson’s organ, where the odor is sensed

Materials – images of many different snakes showing: camouflage, tongue, rattle, etc.

Directions –1. Break the class up into small groups of 3-5 students.2. Review the many snake adaptations that have been discussed.3. Explain to the groups that they will be designing their very own snake. Ask guiding

questions, such as: Will it be large and slow or small and fast? Will it be camouflaged so itcan’t be seen, or will it have bright colors to warn would-be predators?

4. In their groups, the students will work together to determine what their snake will look like,what it eats and then draw a sketch of it. Each student should suggest at lease onecharacteristic for the group’s snake. Have each group present their snake to the rest of theclass and show their sketch.

Questions for discussion – How does a snake’s lack of arms and legs actually help it to survive? Howdoes a snake’s forked tongue help it to smell?

Website/books/other resources – A Snake Mistake by Harriet Ziefert and Mavis SmithSnakes: Biggest! Littlest! by Sandra MarkleThe Snake Who Was Afraid of People by Barry Louis Polisar and David Clarkhttp://montereybay.com/creagrus/CAsnakeSFGarter.htmlhttp://www.californiaherps.com/snakes/pages/t.s.tetrataenia.htmlhttp://www.parksconservancy.org/our-work/park-stewardship/species/san-francisco-garter-snake.html

Current Event, San Francisco garter snakes relocated during construction -http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2000/01/27/MN70501.DTLChildren’s Book – Vernon and the Snake by Crystal J. Stranaghan You can read this story fromVernon’s perspective and then turn it over to hear the snake’s version of the story.

Taking it FurtherTongue TwistersSam saw a sneaky slimy snake in the sandbox.The silly snake swam slowly in the stream.

Conservation Action – San Francisco garter snakes live near ponds and marshes where they have easyaccess to their primary food source, red-legged frogs. Wetlands like these are disappearing due todevelopment and are sensitive to pollution. One great way to help take care of your local ponds andmarshes is to conserve water. Here are a couple of easy ways you can help:

While waiting for hot water to run from your faucet, collect the cold water and use itto water indoor and outdoor plants.

Take shorter showers – challenge your family members to see who can take theshortest shower and still get clean!

Source - http://www.backyardnature.net/snakadap.htm