TURTLES AND TORTOISES Pamela M. Rose, Docent Class of 2002 Docent Training, January 2011.

TURTLES AND TORTOISES

Pamela M. Rose, Docent Class of 2002Docent Training, January 2011


are REPTILES



What does that mean?



Ectothermic, oviparous, “scales” – in this case, a protective shell



Basically lizards with a suit of armor



Can you identify these specimens?




South American Red footed tortoise




South American Red footed tortoise – located in our Reptile House

and…




South American Red footed tortoise – located in our Reptile House

and… in the Education Dept. = Jabuti




Eastern box turtle




Eastern box turtle – Located in… ???




Eastern box turtle – Located in… Education Dept. =

Timmy




Eastern box turtle – Located in… Education Dept. = Timmy

Are there other box turtles at the Zoo?




Eastern box turtle – Located in… Education Dept. = Timmy

Are there other box turtles at the Zoo? YES! Indochinese box turtle in the Reptile House




African Pancake tortoise




African Pancake tortoise – located

in… ??




African Pancake tortoise – located in…

Reptile House





Reptile House

What is the signature feature of this particular tortoise?





Reptile House


Shell is flattened due to ability to squeeze itself into small openings to escape predators





Reptile House


Shell is flattened due to ability to squeeze itself into small openings to escape predators – thus we cannot say that ALL tortoises have rounded shells =

always exceptions in the animal kingdom




North American spotted turtleClemmys guttata





Located in… ???





Located in… Reptile House and Education Dept. = Clemm


What is the difference between a turtle, a tortoise

and a terrapin?

Red-eared slider turtles Galapagos tortoise

Diamondback terrapin


What is a Chelonian?


In general, Chelonian is a good scientific umbrella term = order

Chelonia, from the Greek word for tortoise


Terminology differs depending on endemic area of the world in which

species reside


For example, in Australia, only sea turtles are called “turtles” – all others

are “tortoises”


Spend most of their life in water

Hard shells (are their exceptions… ???)

Turtles


Spend most of their life in water

Hard shells (are their exceptions… ???)

YES – soft-shelled turtles have fewer bones, cartilaginous plastron and a leathery covering

Turtles (cont.)


Spend most of their life in waterHard shells (are their exceptions… YES – soft-shelled turtles have fewer bones, cartilaginous plastron and a leathery covering)Varying degrees of webbing on feetFlattened legs for swimmingLive in fresh water (ponds and lakes) and the seaClimb out onto banks, logs, or rocks to bask in the sun. Burrow into the mud in cold weather - go into torpor until springSea turtles especially adapted with long feet that form flippers and a streamlined body shape – exit water only to lay eggs

Turtles (cont.)


Straight necks - Cryptodira - all North American turtles

Side necks - Pleurodira - refers to the way the turtle withdraws its neck into its shell (they curve neck around and tuck it along the side)

Lifespan

slow growth pattern, mature at 5-7 years

depending on species, 25-50 years (red-eared sliders commonly 40, some Eastern box turtles alleged to make it to 100)

Turtles (cont.)


Live on landRounded or domed shells rather than shells streamlined for water (are there exceptions? – remember our Pancake tortoise)Eat low-growing shrubs, grasses, and even cactus Elephantine hind legs, shovel-like forelegs for diggingLifespan

Some species live 200+ yearsRed-footed tortoise 50-60 years

Largest tortoise: Galapagos >500 lbs. Smallest tortoise: Speckled Cape Padloper < 3”

Tortoises


Spend time in water and on landInhabit brackish, swampy areas in eastern and southern U.S. coastTerm not commonly used except for this particular speciesMalaclemys terrapin terrapin (for you taxonomists)Diamonback terrapin is the official reptile of what state?

Terrapins


Spend time in water and on landInhabit brackish, swampy areas in eastern and southern U.S. coastTerm not commonly used except for this particular speciesMalaclemys terrapin terrapin (for you taxonomists)Diamonback terrapin is the official reptile of what state? -- Maryland, also official mascot of U. of MD College Park; protected in MDIUCN NT=near threatenedCheck out http://www.terrapinconservation.org/

Terrapins (cont.)


Plastron = lower/under shellCarapace = upper/top shell

To which structure is the carapace attached?

Chelonian parts


Plastron = lower/under shell

Carapace = upper/top shell

To which structure is the carapace attached? RIGHT! The spine!

Chelonian parts


Evolution

Permian – 290-248 million years agoAncestors of first turtles (possibly Owenetta) living in Oklahoma

Triassic – 248-206 million years ago

Oldest known turtles from late Triassic: Odontochelys (only carapace and had teeth) and – within just 10 million years – Proganochelys (carapace and plastron, vestigial teeth, spiked neck and tail, could not retract head)

Jurassic – 206-144 million years ago

Cretaceous – 144-65 million years ago


Ribs are immovable, so unable to breathe like other reptiles or mammals. Instead, abdominal muscles perform the function of the ribs: two muscles enlarge the chest cavity to breathe in, and others press the organs against the lungs to force the air out.Tortoise carapace hardens about 3 years after hatchingEastern box plastron hinge firms up 2-6 years (Eastern box)

Development and Function


As the shell (made from keratin) grows, the number of scutes remains the same, but each becomes larger.

In some turtles, old scutes are shed and replaced by larger, new ones. In other species, including box turtles, tortoises, and wood turtles, scutes enlarge in diameter as new keratin is laid down. Scutes that cover both halves of the shell are grouped and named - used in species recognition

Development and Function (cont.)


Age estimation based on growth layers, however, can be erroneous for several reasons:

Some turtles produce multiple growth zones per year. Growth is determined by stressors in the environment, so age determination by examination of growth rings would be less accurate in wild turtles, than those kept in environments which do not change significantly.Growth layers may wear with age, so older turtles may be estimated to be younger than they really are.



Shell is a marvelous product of evolution - collar bone and pelvis have been moved inside the rib cage which is then fused to the shell. Somehow the ancestral form managed this feat -- so successful that very few changes have been made to the basic turtle morphology in over 200 million years.



Turtle shells develop as embryonic ribs which eventually outgrow and enclose the shoulder and hip bones, forming the upper shell (carapace) and lower shell (plastron). The backbone fuses with the flattened ribs, forming a rigid bony case for the vital organs.



Legs have to be sturdy and dense for support so leg bones have little marrow for blood cell production

Carapace has channels and spaces that produce red blood cells



Shells differ in protective ability: soft-shelled turtles including Leatherback sea turtles have a type of thick skin rather than hard shell. Box turtles hinges provide added protection to soft internal organs BUT may not be fully functional until about 6 years old. NOTE that mud and musk turtles have hinged plastrons, but they don’t fully close



Snapping Turtles! Not very well protected by their shells. The plastron in particular is tiny and doesn't begin to cover the animal. Compensate by fierce defense if threatened and ability to swing neck around greater than half-way back so, what does one NEVER do?



Snapping Turtles! Not very well protected by their shells. The plastron in particular is tiny and doesn't begin to cover the animal. Compensate by fierce defense if threatened and ability to swing neck around greater than half-way back so, what does one NEVER do? RIGHT! Never pick up a snapper with your hands, even toward the rear sides of the shell. Use a stick to help move off the road.Signature of a Snapping turtle is the V-shaped cuts in back of plastron.



Hearing: internal ear structures, although hearing isn't very important because their senses of vision and smell are excellent.Vision: seven types of cones for color reception give turtles the most complex cone system described for vertebrates. Many turtles have a horizontal black line running through their pupil that remains horizontal and parallel with the horizon even when the turtle is held vertically, suggesting that the line serves an optical purpose, perhaps to detect polarized light.



Yellow-spotted Amazon River TurtleLocated in the Rainforest A type of side-necked turtle (waay cool!) – what term was that again?

Other Turtles at the Zoo


Yellow-spotted Amazon River TurtleLocated in the Rainforest A type of side-necked turtle (waay cool!) – what term was that again?RIGHT! Pleurodira CITES II designation



Giant South American River TurtleLocated in the Rainforest These turtles engage in mutual groomingSex of hatchlings determined by temperature of the nest Endangered and protected



Largest turtle: Leatherback 95” head-tail Leatherbacks maintain core body temps higher than surrounding frigid water (30-40 degrees), disputing the “cold blooded” label. They primarily eat jellyfish -- esophagus has many backwards-pointing, stiff spines which aid in swallowing soft-bodied foods. Incapable of chewing hard prey due to their weak jaws.

Largest tortoise: Galapagos >500 lbs. Located in the RainforestNo venomous or poisonous turtles (no teeth or venom sacs)Baby turtles tend to be carnivores, adults omnivores, most tortoises are herbivores (but NOTE: our Jabuti is sometimes offered pinkies!)Young Loggerhead Turtles have an amazing navigation system, involving detecting magnetic fields Stinkpot or Musk Turtle (Maine) lets off musky smell when disturbedWood turtles, or “woodies" (Maine) thump the ground to make worms think it's raining so they come up, then get eaten

Fun Facts!


Spotted turtle: Lifespan up to 30 years, mature at 8-10 yearsnest temperature dictates sex: cooler=more malesspot distribution varies and changes with agesexually dimorphic: males elongated carapace and thicker, longer tail, dark jaws while females have yellowish color on jawsSpecial concern in NYS Habitat loss, sensitivity to pollution and toxins, and pet trade threatsClemm, 5 years old, is a “no touch” animalHow did Clemm get is name? Clemmys guttata

Fun Facts!


Red footed tortoise: Lifespan 50-60 yearssexually dimorphic similar to Eastern boxUsed for food – in South America, tortoises are considered "fish" by the Catholic church and during holy week, red-foots are consumed in huge numbers During mating make a clucking sound like a hen“Jabuti” is the species name in BrazilCites II

Fun Facts!


Box Turtles: Shell so is so strong it can readily support weight 200 times greater than its own (this DOES NOT mean you can stand on Timmy!)slightly sexually dimorphic… males have longer, wider tails, more flattened shells, orange or red eyes, and a slightly concave plastron. Females have brown or light orange eyes and a very flat plastron.able to eat mushrooms which would make humans sick, and thus if humans eat box turtles they may become illFemales can store sperm up to 4 years, so can lay eggs for several seasons from one matingEven though turtles are considered aquatic as a group, box turtle feet are only slightly webbed, shell is more tortoise-likeState reptile (and only land turtle) in North CarolinaLifespan 30-40 years in the wild, may live up to 100 in captivity: Timmy is 35CITES II – threatened due to habitat loss and pet trade

Fun Facts!


TURTLES AND TORTOISES Pamela M. Rose, Docent Class of 2002 Docent Training, January 2011.

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