Florida Chicken Turtle -  Deirochelys reticularia chrysea

          Eastern Chicken Turtle -  Deirochelys reticularia reticularia

          Western Chicken Turtle - Deirochelys reticularia miaria

Chicken turtles are medium (males)-to-large (females) basking turtles & females achieve fair bulk (females roughly on par with female RES, but males smaller than male RES). The carapace has a brown to grey base color with a distinctive reticulate pattern (think ‘irregular chain link fence’). The plastron tends toward plain yellow. There's a single broad yellow stripe down the front of the fore-legs. Between rear leg & tail is vertical striping. They are famous for having very long necks (by U.S.A. standards; they don’t reach true ‘snake neck’ proportions. They do carry the nickname ‘American snake neck’). Some have an upward-angled light stripe from the rear of the mouth to the nose,  giving them an upturned snout look (like a hognose snake, but the snout doesn't actually turn up), sort of a smiling expression (vaguely like a male common map turtle). There's a bar or partial bar across the eye pupil.

Florida chicken turtles have the more ornate reticulations & possibly head striping (the 'loudest' coloration). Keith B. described some stereotypical sub-species differences (warning: not all individuals will match these, & intergrades are expected):

1. Florida Chicken - Broad orange or yellow lines on the carapace, a wide color band on the carapace rim, no markings on the plastron.

2. Eastern Chicken - Duller in color compared to Florida chickens, narrow green or brown lines on the carapace, a more narrow color band on the carapace rim, black markings on the underside of the lateral & rear marginals.

3. Western Chicken - Flatter carapace, broad but faint lines on the carapace, dark markings along the plastron seams (Note: Paul V. (Chelidman) noted the Western is the only sub-species with plastral markings)& apparently no markings on the underside of the neck & chin on adults (although an adult in Turtles of the World Vol. 2²⁰ Page 39 with dark carapacial markings does show a striped chin & underside of the head!).Turtles of the World Vol. 2²⁰, Page 39 depicts a Western chicken with dark plastral markings but striping on the chin & underside of the head; Tom C.'s male sub-adult Western has a plain underside of the head but lacks notable plastral markings! Chelidman commented that the general rule of thumb is western s have markings along the plastral seam and reduced or absent striping on the underside of the neck, but some show divergence from that.

Greg notes adult female Florida Chicken Turtles tend to get much larger & bulkier than the other subspecies, with larger, domed shells necessitating more enclosure space (Note: a number of Florida turtles have more domed shells, including the Florida Redbelly Turtle and Florida Snapper; it’s been speculated this may be an anti-alligator adaptation). However, Cris notes chicken turtles have thinner, weaker shells than some basking turtles (i.e.: sliders), & tend to inhabit seasonal wetlands (where alligators don’t predominate). But be warned; adult females of any sub-species are quite large.

Size: 4-6 inch carapace length; record 10 inches¹ (Note: I consider the Peterson’s typical size figure quite conservative & expect many captives will exceed it. Patrick has a male with a 6 7/8” carapace). Females are over 1.5 x’s larger than males³. Turtle Pimp has an 11" SCL female. Males have longer, thicker tails with a more distal vent (past the carapace rim), as also seen with sliders & map turtles.

 Temperature Range (°F): (All ranges are estimates)

• Air Temperature:  Mid. 70’s to 80’s

• Basking Temperature:  Roughly 85-90º

• Water Temperature:  Roughly mid-70'sº; go with 80º the first few months of life

CARE DIFFICULTY

Usually ‘no.’ For a dedicated person, yes. Females in particular don’t stay small like Southern & Midland Painteds or some male map turtles (i.e.: Texas & Cagle’s maps), & are moderately expensive. I strongly recommend choosing a male (for the smaller size). If this turtle will be kept outside & hibernated, I recommend against the Florida subspecies since through much of their natural range hibernation might be minimal or unnecessary. In Keeping and Breeding Freshwater Turtles² (Page 117), Russ Gurley notes baby chicken turtles are a little more delicate than slider babies.

CAPTIVE DIET

In Keeping and Breeding Freshwater Turtles², Russ Gurley states chicken turtles exhibit a carnivorous feeding pattern & hatchlings & youngsters feed on aquatic insects, tadpoles & crayfish. In Greg’s experience chicken turtles are aggressively carnivorous, much more so than, say, cooters, & given opportunity will kill large numbers of fish in a day. They can expand their throats to ‘vacuum’ assist capture (this may cut down on water resistance during the strike, rather than sucking prey in¹⁹). In Turtles of the United States and Canada¹⁸ (Page 365), research is cited & a claim made that during the first year they’re at least partially carnivorous¹¹, but adults probably more omnivorous (it’s stated adults take romaine lettuce but juveniles refuse plant material). It’s noted the chicken turtle has a well-developed hyoid apparatus to literally suck in food items (as Greg has seen).

I am not aware of any stomach content studies providing occurrence by frequency or volume of plant or animal matter, or a breakdown of just what’s eaten. Given their long necks, vacuum-strike technique & carnivorous bent it seems likely they may have greater ability to catch small fish than, say, sliders & painteds. It seems reasonable to figure varied invertebrates (insects, larvae, crayfish, etc…), tadpoles & occasional small fish are dietary fixtures.

Based on the available information, I recommend proceeding on the assumption chicken turtle hatchlings are carnivores that progress to predominantly carnivorous adults. This is not unlike some map turtles, with the caveat we don’t expect chicken turtles to eat intact shellfish (as some female maps can) & map turtles lack the expected chicken turtle fishing capability. Patrick finds his love catfish nuggets & fillets. These could be a treat. His turtles also eat vegetation (collard greens, water hyacinth, iceberg & romaine lettuce, & they love algae).

Hatchlings may be offered a moderate protein diet once daily, graduating to every other day after 6 to 12 months. Romaine lettuce, Anacharis, Water Hyacinth & other safe edible aquatic plants should be offered often to encourage low-protein intake (daily romaine lettuce is fine). Choose a good brand name commercial food (i.e.: Mazuri, ReptoMin, etc…) & augment with live food offerings (crayfish, earth worm, cricket, etc…). Some people cut dietary protein by using some commercial tortoise food. As discussed under Hatchling Care, Diet, include small crayfish or shrimp & Hikari vitamin-enriched frozen bloodworms.

RECOMMENDED FEEDING SCHEDULE

Our standard recommendations would state for the first 6 months of life, feed commercial pellets or meaty foods such as earthworms or fish once daily, enough to diminish appetite but not gorge the turtle. (As discussed under Hatchling Care, Diet, I recommend feeding moderate amounts twice daily the first month.) After 6 months, switch to every other day feeding. Romaine lettuce, Anacharis, Water Hyacinth & other safe edible aquatic plants & other leafy greens may be offered daily for graze at will (if your chicken is an odd-ball & likes plants) to encourage low-protein intake (daily romaine lettuce is fine). Over time adjust diet content & schedule accounting for growth, activity level & appetite. Overfeeding high-protein foods can cause rapid growth& is believed harmful to the liver & kidneys.

However, an experienced Florida breeder produces live food in an outdoor container (variety of organisms, including tiny native shrimp) & offers enough food daily that hatchlings may forage at will. He believes they do better with food available all the time (Turtle Pimp also favors feeding vigorously). However, much of their intake will be very small food items, & live prey items include substantial indigestible chitin (exoskeleton) & are largely water, unlike nutrient-dense commercial turtle foods (like ReptoMin). That said, spreading the food over the course of the day is more natural so try giving hatchlings at least twice daily small feedings. This same breeder has noted better hatchling survival since adding Hikari vitamin-enriched frozen bloodworms to the diet (Hikari sells vitamin-enriched & not; use the former) so I recommend including some in the diet.

You may optionally feed hatchlings & young juveniles a few times daily, with the stipulation you exercise the discipline to spread the food supply over the day rather than increase it over what would be given once daily.

WILD & CAPTIVE HABITAT

Chicken turtles are considered basking semi-aquatic turtles (along with sliders, cooters, painted & map turtles). Turtles of the United States and Canada (Page 359) states they inhabit still waters (including ponds, lakes, ditches, marshes, cypress swamps & Carolina bays), normally with ample amounts of aquatic vegetation and a soft bottom. South Carolina-based research⁴ shows Eastern chicken turtles are capable living in ephemeral habitats (such as South Carolina Bays, whose water levels drop over summer); they can burrow into upland forest floor (‘refugia’), presumably to escape drought. (Note: Carolina Bays are unusual habitats where water levels drop a lot over the summer & can create bad conditions & concentrate turtle populations leaving them vulnerable to predators; fleeing to upland refugia (typically late summer to early autumn) may provide shelter from poor environment & predators)⁴. Chicken turtles can migrate overland when the need arises, but one study found Eastern Chicken turtles less likely to emigrate from a drying habitat than YBS & Florida cooters (though they decreased reproduction), & noted most populations in that region were associated with fluctuating, non-permanent bodies of water⁶. Turtles of the World (CD Edition)¹⁷ notes sometimes large aggregations can be found in temporary pools, & states that apparently they don’t live in moving-water habitats. Chicken turtles hibernate through colder parts of their habitat.

Cris drew on his experience & contacts to note they seem to predominate in seasonal wetland habitat rather than large, permanent water bodies. Cris suspects this may be to avoid alligators (given their thinner, weaker shells). What’s more, they will head overland & burrow (shallowly) into forest floor, whereas sliders & cooters abandoning a water body seek another instead.

Patrick reports that they are very secretive in the wild (& suspects adults bask less than juveniles). However, Greg said his have always basked only ‘the slightest bit less’ than cooters & sliders. My impression from forum experience is that they are much harder to field herp than sliders, painteds & cooters.

Turtle Pimp noted chicken turtles (including hatchlings) burrow into mud to roust out crayfish, & in his experience in Florida around mid-afternoon (between 3 & 4:00 p.m.) they'd burrow into the mud in shallow water looking for crayfish, heads first into the mud.

RECOMMENDED ENCLOSURE

The basic layout is that of a standard semi-aquatic turtle setup; largely aquatic with a good-sized basking platform (which dries completely to maintain plastron health) large enough to allow the turtle to choose its distance from the heat lamp & self-regulate its temperature. Since still sluggish vegetated waters are preferred in nature, avoid strong currents & loudly splashing water, & provide tank ‘furniture’ (driftwood, plastic or live plants, etc…) to provide a complex environment to interact with.

Patrick finds his like to move their heads & necks amongst branches (think mangrove-like), & are very inquisitive. PetsMart & other pet store chains offer synthetic resin stumps & roots that may serve this purpose.

I recommend an enclosure no smaller than a 75 gallon aquarium for 1 to 2 adult male chicken turtles, and no smaller than 125 gallons for a large female. The enclosure should have adequate water depth (at least 2/3’rds full, but beware escape by climbing out) & a large basking platform that dries completely. If you are to breed them, a larger enclosure with a nesting site is needed.

Patrick notes they love the bottoms of ponds (20” depth in his), & Greg notes the famous ‘I-4’ (a wild-caught female Florida chicken turtle) seems to enjoy relaxing on the bottom when not feeding or basking, floating at the surface when basking and chasing minnows, and tends to bask before the other turtles steal the spot (Greg goes at least a foot deep). With this in mind, plan on a fairly deep enclosure if you can.

WATER DEPTH

For adults, plan water depths at least 1.5x SCL; the same guideline is fine for hatchlings, although with time you can offer juveniles deeper water with the stipulation you provide plenty of underwater 'furniture' for support (i.e.: driftwood, synthetic rocks & logs, plastic plants, etc...).

COMMUNITY HABITAT

Few enough people keep chicken turtles to make comments anecdotal, but I've neither experienced nor heard of any problems keeping chicken turtles with other species, as long as those tank-mates are non-aggressive. One exception - my young adult male appeared very interested in my juvenile spiny softshell & fearing imminent attack I have kept them separately since. Chicken turtles will compete directly with tank-mates for food (i.e.: 'tug-o-war') & can cause or receive scratched eyes & such. Be warned adult mud turtles are known to prey on hatchling chicken turtles; don't expose hatchlings to much larger turtles of any species (this applies to hatchlings of any species).

The main restrictions on tank-mates are enclosure needs (cooters, sliders, painteds, maps, musk) have similar needs.

Breeding – Chicken turtle egg laying patterns vary with region. They’re unusual in having a ‘winter nesting pattern.’¹⁶ Those in South Carolina were noted to nest late winter/early spring and fall/early winter^{7,12,13, 16}, whereas those in Florida did so continuously mid-Sept. to early March¹⁶ (Florida is partly semi-tropical, which may account for the difference). Females can retain their eggs for months (possibly in response to unfavorable conditions)¹⁴. They are noted to undergo diapause (arrested development) & require a period of chilling to resume development^9,10. In Keeping and Breeding Freshwater Turtles³ (Page 117), Russ Gurley states in warmer climates females lay multiple clutches of eggs (6-10/clutch) which hatch in 75-85 days depends on incubation temperature, & recommends 82ºF & 75-85% relative humidity for a mixed male/female crop (he didn’t mention diapause). Sex determination is temp. dependent so you can choose their gender! Turtles of the United States and Canada (Page 364) states 100% of eggs incubated at 25ºC produce males, but at 30ºC only 11% were males¹⁵.

Ron Allen in KY incubated a batch of eggs; he acquired a batch of 7 eggs (presumably Florida chicken, but taken from the Gainesville area close enough to Eastern range for possible intergradation) in August. He incubated 5 at a constant 82º & none hatched. He incubated 2 at that same 82º but after ~ a month he cooled them in his basement (to maybe the mid. 60’s?) for ~ 1.5 months, then resumed 82º incubation – both hatched.

Cris Hagen knows a scientist who’s hatched eggs and been involved in scientific research on chicken turtles. After consulting with him, Cris relayed the following info. The eggs are incubated normally (28-30ºC) for a couple of weeks after they’re laid. Then put them in a refrigerator (or other cool environment) for 1-2 months. Then resume normal incubation & they should hatch in 70-90 days! Cooling the eggs down for a month or more is thought crucial or else embryonic development will not resume from diapause & they die.

Turtle Pimp was aware of an outdoor breeder who places a wire cage (roughly 3' x 18" x 18" screen enclosure) around the nest & when it gets close to hatching time attaches a long wire mesh tube that extends to the water and on the end of the wire tube there is another semi-submerged wire cage to keep the hatchlings from getting free into the pond. (Note: Moles are a significant predator of nests).

In Keeping and Breeding Freshwater Turtles (Page 117), Russ Gurley notes baby chicken turtles are a little more delicate than slider babies. That's an understatement; we've had healthy hatchlings in appropriate enclosures with skilled keepers die a few days later for no clear reason (2 of our members had this happen with 1 each). For that reason, I advise a regimen of 'best care practices' with some measures that might be useful in theory:

1. Have the setup already going for a few days before you get the turtle.

2. Start out with fairly shallow water (~ 2x SCL) to minimize stress & exertion.

3. Use very clean water. We don't know much about the impact of pH, so check pH & make sure it's not extremely acidic (< 6.0) or alkaline (> 7.6) & if it's too alkaline add some distilled water (sold at Wal-mart) to dilute the water's buffering capacity & reduce the pH toward neutral. It's highly unlikely tap water will be acidic. This is a theoretical concern, not one that's been shown to matter.

4. A few live plants like some strands of Anacharis to help maintain water quality should be good.

5. Provide plenty of cover (i.e.: plastic plants & a hide-cave) to provide a sense of shelter/protection & minimize stress.

6. Use a dechlorinator that also handles chloramines; it's thought chlorine can harm intestinal flora in turtles.

7. Use a turtle 'sulfa block' (i.e.: Dr. Turtle) the first few weeks to cut down on bacterial counts in the tank & in theory possibly reduce the risk of acquiring infection. (Note: the whole block will dissolve in even a small amount of water, so break off a piece sized for the water volume you're using (1/2 for 10 gallons, 1/4 for 5 gallons, etc...).

8. 80 degree water - let's make sure those immune systems are working well. After a few weeks you can reduce to 76-78ºF.

9. Provide a good, warm basking spot from the word 'Go' so that turtle can get warm & fight off infections better if it needs to.

10. UV-B lighting right away - preferably fairly strong - sunlight is reputed to have healing power for turtles, but isn't an option for most indoor keepers (be very careful to prevent rapid over-heating if you try exposing hatchlings in small containers outdoors). A Repti-Sun 5.0 Tube bulb would be a fine choice (ideally in a hood with a reflector).

11. Feed daily but don't gorge them. We know baby smooth & spiny softshells can gorge & die (Timdog suspects they may take in so much the lungs have too little room to expand; why is less an issue than that this is known to happen, so in theory it could threaten any hatchling).

12. Don't try feeding outside the main tank the first month of life - the theoretical point is to minimize stress. And don't take them out for photos the first 2 weeks (theoretical concern re: stress).

13. Cover enough of the tank so there aren't drafts & the air stays warm.

14. Don't mix with other turtles or their things the first month of life; why expose to disease when it's new & stressed?

15. Make sure the room never goes entirely dark. It's thought in deeper tanks Eastern & Mississippi muds, and baby 3-striped muds, may be at drowning risk. No reason to suspect it of chicken turtles but I say why take a chance? A night-light, or a nearby fish tank with the hood light on, could do the trick.

DIET

Content same as adults, with feeding schedule covered under Recommended Feeding Schedule. However, Turtle Pimp noted that hatchling chickens survive on bloodworms and baby crayfish. Nothing else! They may eat everything in sight, but these two foods are the only thing that seems to get them over the 'hatchling hump.' He suspects they have a high calcium need & said despite being good 'fish-nabbers' crayfish are what they eat most. For the bloodworms, I recommend Hikari vitamin-enriched frozen bloodworms. The experienced Florida breeder who breeds them outdoors has a vat in which he propogates lives foods, & he gives his hatchling chicken turtles about as much shrimp as they'll eat! (That's in Florida; they have some species of grass shrimp). Turtle Pimp also favors feeding vigorously, has raised many hatchlings, & for him they did best on baby crayfish & mayfly larvae. For that reason, I recommend feeding moderate quantities twice daily the first month of life to get them started, but I don't recommend completely gorging them. Chelidman noted hatchlings can be difficult feeders, refusing any kind of pelleted food for 6 months to a year, & said it's best to start them on natural food (frozen or live is fine) and you can try to wean them over to pellets later by keeping them with baby turtles that do take pellets.

Personality: Patrick finds his to be inquisitive & quite personable turtles. In the wild they’re considered quite wary baskers.

Availability in the Hobby: The Florida subspecies seems most common in the pet trade. Not common but can usually be found with persistence (much less common on dealer lists than sliders, painteds & cooters; similar to Blandings). Hatchings tend to cost ~ $50-75 apiece. I found 1 2-3” yearling for $115 with free shipping (by Underground Reptiles) and a 4” Florida chicken turtle for $75.00 (Abbott’s Turtle Farm). Phil Peak said from what he understand wild-caught adults often fare poorly & are often plagued by a form of shell rot, especially in the western part of their range (such as La), much like the bacteria that attacks the rear marginals in razorback musk from that region. Fortunately captive-bred hatchlings are available.

Longevity: Cris suggested we mention “…that Deirochelys is one of the shortest lived of all the Emydids. Males are mature by age 2, females by 5. They die between age 12-15. In captivity they may live 18-20 years.”

Personality: Patrick finds his to be inquisitive & quite personable turtles. In the wild they’re considered quite wary baskers.

Hibernation: Turtles of the United States and Canada¹⁸ (Page 362) states at least in the northern part of their range these turtles hibernate in mud & aquatic vegetation, but in Florida don’t (remaining active except on cold days). But Cris notes they can & do hibernate on land, as well. He provided a paper⁴ stating Deirochelys & Kinosternon subrubrum were commonly found in terrestrial refugia during late summer through winter at distances up to 165 m (average duration 185 days) & 135 m (average duration 170 days) (respectively) from the delineated wetland boundary. However, in Cris experience keeping chicken turtles outdoors in South Carolina (mild to moderate winters; cold periods with a few weeks of days roughly 45-60º, nights roughly 20’s-30’sº) an Eastern chicken turtle can survive in a large well-vegetated stock tank. He doesn’t recommend outdoor hibernation in climates with extended periods of sub-freezing weather (occasional cold snaps may be okay; 3 or 4 months straight freezing temp.s is not).

Subspecies Differences: Hard to provide in detail given the scarcity of info.; much of our research base is on Eastern Chicken Turtles in South Carolina, yet The Florida subspecies has a more continuous nesting season vs. the Eastern, in keeping with the semi-tropical vs. temperate habitat difference. Greg notes female Floridas are larger & bulkier with larger, domed carapaces. My Speculation: Eastern & Western have more temperate climate ranges so I predict their hibernation fitness & cold tolerance may be greater.

XII.) Useful Online Resources

             U.S. Army Corp of Engineers Western Chicken Turtle Information Sheet.

An Online Research Summary News Release about Chicken Turtles.

eNature.com’s Chicken Turtle Profile.

            Virginia Fish & Wildlife Info. Service – Chicken Turtle Page.

Corkscrew Swamp Sanctuary’s Chicken Turtle Entry – (Note: they claim the adult Florida Chicken Turtle’s diet is primarily vegetation, in contrast to the information I got from other sources).

World Chelonian Trusts Photo Gallery on Chicken Turtles

XIII.) Useful Books 

1.)    Turtles of the United States and Canada - Roger Conant and Joseph T. Collins. (Excellent natural history reference for North American species).

2.)    Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles – A. C. Highfield. (Excellent general husbandry guide, but its species profiles do not include the chicken turtle!).

3.)    Keeping and Breeding Freshwater Turtles – Russ Gurley. (Another fine general husbandry guide – does have a 1.5 page profile on chicken turtles).

XIV.) Credits

             Authors/Contributors:

First Author: Richard Lunsford

A Florida Breeder who preferred anonymity.

Greg Brashear

Patrick Carew

Cris Hagen

Phillip Peak

Ron Allen

Keith B.

Turtle Pimp

Paul V. (Chelidman)

Bob MacNally

Belinda

* Special Thanks to Cris for sending me some scientific research papers; good info. & interesting reading.

XV.) Bibliography

1.) A Field Guide To Reptiles and Amphibians of Eastern/Central North America, 3’rd Ed. (The Peterson Field Guide Series). Roger Conant and Joseph T. Collins. Houghton Mifflin Company, Boston, New York. Page 187.

2.)    Keeping and Breeding Freshwater Turtles – Russ Gurley, Director, Turtle and Tortoise Preservation Group. 2003. Published by Living Art Publishing & Russ Gurley.

3.) Gibbons, J. W. and J. E. Lovich. 1990. Sexual dimorphism in turtles with emphasis on the slider turtle (Trachymys scripta). Herpetol. Monogr. (4): 1-29. (This reference was cited in Turtles of the United States and Canada).

4.) Buhlmann, Kurt A. and J. Whitfield Gibbons 2001. Terrestrial Habitat Use by Aquatic Turtles from a Seasonally Fluctuating Wetland: Implications for Wetland Conservation Boundaries. Chelonian Conservation and Biology, Vol. 4, Number 1: 115-127.

5.) Bennett D.H., J.W. Gibbons, and J.C. Franson, 1970. Terrestrial activity in aquatic turtles. Ecology 51:738-740. (This reference was cited in Turtles of the United States and Canada).

6.) Gibbons, J.W., J.L. Green, and J.D. Congdon, 1983. Drought-related responses of aquatic turtle populations. J. Herpetol. 17:242-246.

7.) Gibbons, J.W. 1969. Ecology and population dynamics of the chicken turtle, Deirochelys reticularia. Copeia 1969:669-676.

8.) Gibbons, J.W., and J.L. Green. 1978. Selected aspects of the ecology of the chicken turtle, Deirochelys reticularia (Latreille) (Reptilia, Testudines, Emydidae). J. Herpetol. 12:237-241. (This reference was cited in Turtles of the United States and Canada).

9.) Ewert, 1985. Embryology of turtles. (In Gans, C., F. Billett, and P.F.A. Maderson, eds. Biology of the Reptilia, vol. 14, Development A, 75-267. John Wiley & Sons, New York). (This reference was cited in Turtles of the United States and Canada).

10.) Ewert, 1991. Cold torpor, diapause, delayed hatching and aestivation in reptiles and birds. In Demming, D.C., and M.W.J. Ferguson, eds. Egg incubation: Its effects on embryonic development in birds and reptiles, 173-191. Cambridge University Press, New York). (This reference was cited in Turtles of the United States and Canada).

11.) D.R. Jackson, 1978. Evolution and fossil record of the chicken turtle Deirochelys, with a re-evaluation of the genus. Tulane Stud. Zool. Bot. 20:35-55. (This reference was cited in Turtles of the United States and Canada).

12.) Gibbons, J.W., and J.L. Green. 1979. X-ray photography: A technique to determine reproductive patterns of freshwater turtles. Herpetologica 35:86-89.

13.) Gibbons, J.W., and J.L. Green. 1990. Reproduction in the slider and other species of turtles. In Gibbons, J.W., ed. Life history and ecology of the slider turtle, 124-134. Smithsonian Institution Press, Washington, D.C. (This reference was cited in Turtles of the United States and Canada).

14.) Buhlmann, Kurt A., Tracy K. Lynch, J. Whitfield Gibbons and Judith L. Greene. 1995. Prolonged Egg Retention in the Turtle Deirochelys reticularia in South Caronlina. Herpetologica, 51(4), 457-462

15.) Ewert, M.A. and C.E. Nelson, 1991. Sex determination in turtles: Diverse patterns and some possible adaptive values. Copeia 1991:50-69. (This reference was cited in Turtles of the United States and Canada).

16.) Jackson, D. R. 1988. Reproductive strategies of sympatric freshwater emydid turtles in northern peninsular Florida. Bull. Florida St. Mus. Biol. Sci. 33: 113-158. (This reference was cited in the Turtles of the World CD & Turtles of the United States and Canada).

17.) Turtles of the World (CD-ROM Edition) - C.H. Ernst, R.G.M. Altenburg and R.W. Barbour. Version 1.0 (Mac), 1.2 (Windows). Springer Verlag. 1998.

18.) Turtles of The United States and Canada –Carl H. Ernst, Jeffrey E. Lovich and Roger W. Barbour. Smithsonian Institution Press, Washington and London. ©1994.

19.) Kinematics of Aquatic and Terrestrial Prey Capture in Terrapene carolina, With Implications for the Evolution of Feeding in Cryptodire Turtles - Adam P. Summer,* Kayvan F. Darouian, Alan M. Richmond & Elizabeth L. Brainherd. Department of Biology and Graduate Program in Organismic Evolutionary Biology, University of Massachusetts, Amherts, Massachusetts 01003.

20.) Turtles of the World Vol. 2, North America - Holger Vetter. Terralog series. Publisher Andreas S. Brahm. © 2004. 128 Pages. ISBN 3-930612-57-7, ISBN 3-936027-52-8.