Care Sheet - Northern Map Turtle

Graptemys geographica

Photo by Jason Folt


Photo by Turtlepower122	Photos by Richard Lunsford
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Note: There's a transition underway moving from the common name 'Common Map Turtle' to 'Northern Map Turtle,' which became official via the SSAR (Society for the Study of Amphibians & Reptiles) a few years back. This change will be reflected in natural history & other works by the scientific community.

General Description: The Northern Map Turtle (Graptemys geographica) is a medium-to-large sized turtle capable of reaching straight carapace lengths of 4 to 6" in males & 7 to 10 3/4" in females (note: there's always the chance an individual will exceed the normal ranges). The Northern map is only one of the 12 currently recognized species of map turtle, a group of basking aquatic turtles native to large permanent water bodies in the U.S. Sexual dimorphism is pronounced.The body form is ‘classic basking turtle’ style, with an oval body form (circular in hatchlings), mildly domed on top & flat-bottomed, blunt head with peripherally-placed eyes & a blunt snout, feet with webbed (& clawed) toes & a small to medium tail. The shell has an internal bony foundation on which are bone plates covered with keratin laminae called scutes. The shell includes a mildly to moderately domed carapace (upper shell) & a hingeless plastron (lower shell); the turtle can withdraw into the shell but the shell cannot close at all (map turtles rely on vigilance, water, rapid swimming & hiding for protection; on land they're vulnerable to predators). The carapace scutes are smooth (note: captives reared too fast with excess dietary protein may have raised scutes (a 'bumpy' carapace) with concentric rings. This is termed pyramiding). In males & hatchlings the carapace is keeled (mildly triangular in cross-section; the sides slope upward to the spine, like the roof on a house) with some 'spikes' (knobs), but adult females have a rounded carapace (often with less keeling & no spines). In hatchlings the plastron has dark color along the scute seams & plastral scutes may have a few spots, but this tends to fade to a bland yellowish in adulthood. As Northern Maps mature & age they typically develop darker, duller carapaces & more subdued/obscured patterns.

Carapace: smooth scutes, keeled (more in juveniles & adult males; females are more rounded), hard, brown to olive base color with small light reticulate patterning (like roads on a map). On top down the spine is a single row of small knobs/spines in adult males & juveniles (may be absent in adult females). Marginal scute undersides have intricate circular patterns. Carapace rear mildly serrated. Northern maps tend to have smaller dorsal spines/knobs than Mississippi maps, and much smaller than black-knobbed maps. The dorsal keeling/knobs of map turtles are absent in sliders, cooters & painted turtles.

Plastron: Moderately sized (more developed than in snappers & musk turtles, less so than box turtles), hingeless (can't close like a box turtle's), cream to yellow base color (hatchlings have dark plastral seams with a few variable dark spots or smudges; often absent in adults).

Head: Males have a blunt face, peripherally placed yellow eyes with a horizontal bar through the pupil & a short snout (vaguely 'frog-faced'). Females have larger, broader heads. They typically have a small vaguely triangular yellow spot directly behind the eye. The head & neck have plenty of yellow striping on a dark skin. On the lower neck just behind the head a yellow line curves up to form a 'C' & in some a similar stripe curves down from the upper neck. Northern map turtles are considered part of the 'broad headed' map group, but this is most readily observed in adult females.

Size & Distinguishing Sex Characteristics: Male Northern Maps are much smaller than females, reaching ~ 4 - 6" adult SCL (vs. ~ 7 - 10 3/4"). Males' carapaces have more keeling & more prominent dorsal spines/knobs. Northern Maps don't have prominently elongated front claws (unlike sliders, cooters & the 'False Map' complex turtles) & their tails are much longer & have a much thicker base than females (broad base tapering to a point making a large triangle, much more prominent than in sliders); with the tail fully extended the cloaca will be past the edge of the carapace. Large females often develop bulky, muscular-looking heads.

As yet there are no common 'color morphs' of the Northern Map Turtle (i.e.: albinos) & should any come on the market pricing will likely be exorbitant.


	The Northern Map Turtle has by far the largest natural range of any map species. They naturally range from the north-central to north-eastern U.S. (extending up to Montana, Wisconsin, Michigan, the northern border of New York, up to southwestern Maine & extreme southeastern Canada) & extend down in 2 separate branches, a west branch descending across Iowa down through Missouri & into Arkansas, & an east branch coming down through Indiana & Ohio through Kentucky & Tennessee into Alabama. Ranges given via my interpretation of Peterson's Field Guide³ range map (Page 168)³. Only the False map and Ouachita maps extend nearly as far north, & neither has such a broad northern distribution. Northern Map Turtles are mainly restricted to large, permanent water habitat such as rivers & large lakes, but are occasionally found in smaller water bodies such as permanent streams (i.e.: 'Little River' in southwestern Kentucky). Map turtles are avid baskers & require habitat with basking platforms. In a Pennsylvania river the most captures occurred in deep, slow-moving areas, large turtles were more often caught in deeper slow areas & smaller turtles in shallower slow areas, and large adults avoided areas with emergent vegetation but congregated in areas with fallen limbs (Pluto & Bellis, 1986)⁷. In The Amphibians and Reptiles of Arkansas (pages 222-223)² authors note larger turtles are more likely to occur in deeper water with swifter current, deeper water with slow currents is preferred for over-wintering, & cites research (Fuselier & Edds, 1994)⁶ indicating they seem to prefer streams with more rock or gravel substrate & shorelines with more shade than Mississippi & Ouachita Maps. Chris Lechowicz noted brush piles (i.e.: fallen trees) along the bank are important to map turtle populations, & offer shelter & habitat for young juveniles. In parts of their range they co-occur with other map species (i.e.: in Tennessee Northern, Mississippi & Ouachita Maps co-occur in some water bodies). Map turtles in general are wary baskers; juveniles can sometimes be approached by boats, older juveniles and males are more guarded and adult females are very hard to approach. Although some species such as Red-eared Sliders & Common Snappers often travel significant distances overland & colonize isolated smaller water bodies such as farm ponds, map turtles generally do not. Maps are more inclined to migrate via aquatic avenues such as temporary floodplains & irrigation/drainage canals. Map Turtles, along with Painted Turtles, are the main 'second tier' basking turtles in the U.S. pet trade (after the phenomenally numerous, wide-spread Red-eared Slider). However, the Mississippi Map turtle is far & away the most populous pet map turtle (in the U.S.), with Ouachita & False maps coming up next. Northern Map Turtles are somewhat uncommon in captive collections, sporadically available from online vendors but persistent searching for a few weeks on online classifieds in later Summer and Fall will turn some up. As of Fall '05 hatchlings ran around $30 apiece + shipping.

TEMPERATURE RANGE (°F)

Air Temperature: mid 70's - 80's
Basking Temperature: Adults: Mid. 80's up to 110º F.* Hatchlings: Mid. 80's up to 100º F.
Water Temperature: ~ 72 to 76 degrees for sub-adults & adults, 78 to 80 degrees for hatchlings & smaller juveniles.
*Cris Hagen reported captive map turtles kept indoors benefit from hotter basking platform temp.s than we typically recommend for basking turtles (i.e.: 85-95 degrees). He said this is a factor in the poor shell condition sometimes seen in map turtles at public exhibits. That said, with temp.s this high be sure to offer a large enough basking platform so the turtle can choose from a range of temp.s (up to 100-110º F, but not restricted to that range).

Northern Maps encounter a range of temperate climates across their range, making them a possible option for a year-round outside enclosure (if it's deep enough) in their native range & elsewhere with comparable (or warmer) climate. Research (Pluto & Bellis, 1988)⁸ documents that in Pennsylvania deep riverine pools are used as hibernacula, & a personal observation by Ernst that in Kentucky impoundments are often used to over-winter. This suggests they don't hibernate in the shallows near shore, so how well they over-winter in shallow man-made enclosures (i.e.: large stock tank, Koi ponds ~ 4 feet deep, etc...) isn't clear. Since local populations over long time periods may be shaped via natural selection to their local environment, in theory Northern Maps from the southern part of their range may not be well-adapted for winters in the northern part of their range. Be mindful of this if outdoor hibernation in the northern U.S. is planned (ask the breeder if he knows where the parent stock originated from). Other options for year round outdoor keeping up north include the Western, Eastern & Midland (but not Southern) Painted Turtles, Stinkpots & Common Snappers (all species on condition of Northern parentage).

CARE DIFFICULTY

Northern Map Turtles are decent beginner turtles for people with large aquariums or outdoor garden ponds (if deep enough) to house them year round. They are not considered particularly delicate but map turtles as a group have a reputation for being problem-prone if water quality isn't excellent; your mileage may vary, but if skin fungus or shell rot arise, check your water! Maps as a group have a reputation for being nervous/skittish around people but many are comfortable around people & vigorously beg for food (some tolerate some handling, some don't), & take readily to both commercial & natural foods. Males are medium-sized; females get quite large and can put a strain on housing. Map turtles lack the 'power strike' of chicken turtles & common snappers, & aren't gifted fishermen. Males are prone to harass females so incessantly permanent separation is often necessary. As with any turtle species, an individual may be naturally aggressive or a pair incompatible. That said, there are other good species who stay much smaller (i.e.: Texas maps & Cagles maps).

CAPTIVE DIET

Throughout their lives, Northern maps are predominantly carnivorous but even juveniles may take some vegetation (such as Anacharis), although not as much as cooters, sliders & painted turtles. Their raw drive to gorge on higher protein foods makes it easy to feed too much protein (causing very rapid growth & a pyramided shell, & suspected to cause liver & kidney damage & shorten life span). Keep a check on the turtle's diet and ensure it gets a low-volume well-rounded diet. There are many foods they eat: Mazuri and ReptoMin, Reptile/Pond 10, Cichlid Sticks, feeder fish, feeder crickets, earthworms, krill, blood worms, occasional crayfish & ghost shrimp; try aquatic plants (such as Water Lilies, Water Hyacinth, Duckweed, Anacharis, Water Lettuce, Water Fern, Pondweed, Water starwort, Hornwort, Water milfoil, and Frogbit) & some vegetables (such as Zucchini, Squash, Collard Greens, Beet Leaves, Endive, Romaine, Red Leaf Lettuce, Kale, Escarole, Mustard Greens & Dandelions). Many keepers use a good brand name commercial diet (usually Mazuri or ReptoMin Aquatic Turtle Diets) for a substantial portion (say, 25 - 80%) of the carnivorous portion of the diet, & round that out with treats of crickets, earth worms, crayfish, ghost shrimp & krill, & use Romaine lettuce (chosen over iceberg for higher fiber) & Anacharis as mainstays for the herbivorous portion of the diet. Since wild Northern Maps likely don't encounter fruits often we don't recommend use of Bananas & other fruits except as rare treats (if your turtle even takes such). Some people offer hairless mouse pups to turtles on occasion; never feed hairy animals to animals who don't naturally eat them (like Northern Maps) since hair is poorly digestible & can form trichobezoars (hairballs) & cause G.I. obstruction in some animals (so in theory perhaps turtles). Bottom Line: Start out using a brand name commercial turtle food (i.e.: ReptiMin or Mazuri) for ~ 25-80% of the diet, add variety with feeder crickets, ghost shrimp & earth worms, & offer Romaine lettuce & Anacharis often.

One critical point: if you keep your map indoors & don't provide UV-B lighting (i.e.: a ReptiSun 5.0 or 10.0 fluorescent bulb), be sure you provide adequate dietary Vitamin D₃. This involves either using a commercial pellet food that includes it, or a powdered supplement like Rep-Cal for feeder insects. Beware using large amounts of food containing Retinol, a form of Vitamin A that (unlike β-Carotene) can interfere with Vit. D₃ absorption in the body. UV-B doesn't penetrate glass well so sunlight coming through a window won't do.

Another critical point: you must provide adequate dietary calcium. The ratio of calcium to phosphorous (preferably 2 or more to 1) is important. Typical feeder insects have a poor calcium to phosphorous ratio, meal worms have a terrible ratio, & it's thought by some advanced keepers calcium-containing 'gut load' feeds may not add enough calcium to feeder crickets.

Insufficient Vit. D₃ or calcium over time can cause soft shell & skeletal disfigurement (Metabolic Bone Disease).

We've a decent research base on wild dietary patterns. In general, Northern Map Turtles are opportunistic predominantly carnivorous omnivores who eat invertebrates & mollusks, & may tailor their diet to a narrower niche due to competition when sharing a habitat with other map species. Peterson's Field Guide³ states snails & crayfish are the chief foods. Turtles of the United States and Canada¹ cites a number of sources on the subject: 1.) Unpublished notes from Fred Cagle stating that in White River, Arkansas males ate small snails & some insects (including trichopterans) while females ate large crushed snails & earth worms (no other prey were found despite an abundance of other invertebrates in the habitat), 2.) (Ernst & Barbour 1972)⁹ listed snails, clams, insects (esp. immature stages), crayfish, water mites, fish & aquatic vegetation as foods, 3.) (Penn 1950)¹⁰ reported crayfish made up 24% of the diet in the eastern U.S., 4.) (White & Moll 1992)¹¹ noted a particular species of small snail made up 94.1% by volume & 98.9% by frequency of food in digestive tracts of adults from a river in Missouri, while crayfish made up 2.9%, and insects & plants 3.0% by volume & 5.) (Vogt 1981)¹² indicated that in Wisconsin (where they co-occur with False & Ouachita Maps) Commons specialize in mollusks to reduce competition (but foods included mollusks, fish, caddis flies, mayflies, damselflies & some plant matter). In The Amphibians and Reptiles of Arkansas (page 222)² authors note snails & clams for the greater part of the diet, & states the broad, flat jaws are indicative of this mollusk specialization.

Note 1: Snails of the genus Goniobasis have been implicated in transmitting the lung fluke Heronimus mollis to loggerhead musk turtles¹⁷, & the snail Physa integra identified as an intermediate host for H. mollis^{18, 19} & both it & Physa gyrina are natural intermediate hosts²⁰. Lung flukes do infect other turtle species, including Midland Painted Turtles & Common Snappers. Aquatic snails are well-known as intermediate vectors of a range of parasites affecting a range of animal species, so we at Austin's Turtles Page do not recommend feeding wild-caught snails, or snails bred in containers with wild (or otherwise at risk to be infected) turtles present, to pet turtles. The extent of the danger of parasitism is theoretical & unclear. Some people do feed their pets wild-caught snails. Note 2: We have an anecdotal report of a young stinkpot being trapped & drowned by a freshwater clam, so be wary of larger shellfish.

RECOMMENDED FEEDING SCHEDULE

For the first 6 months of life, feed commercial pellets and/or other 'meaty' foods (such as earthworms, crickets or fish) once daily, enough to diminish appetite but not gorge the turtle. After 6 months, switch to every other day feeding. Romaine lettuce & other leafy greens may be offered daily for graze at will. Over time adjust diet content & schedule accounting for growth, activity level & appetite. Overfeeding high-protein foods causes rapid growth, shell deformities (pyramiding) & is believed harmful to the liver & kidneys. If the carapace scutes develop a prominent concentric ring pattern &/or thicken, making the carapace bumpy, cut back strongly on protein in the diet or your turtle will have a permanently pyramided shell. While growth rate varies amongst different hatchlings, at 1 year of age we want to see an SCL of 2 to 3.5". At all ages recommendations on the amount of meaty food to offer vary; some suggest enough to fill the head back to the rear of the head if it were hollow, others let the turtles gorge but only feed twice per week, & some simply feed enough to slake appetite a bit. For a 50 cent piece-sized hatchling, I'd start out giving ~ 3 Baby (or 1 regular) ReptoMin pellets per day.

CAPTIVE HABITAT

Northern Map Turtles are avid baskers, so a basking platform with a heat lamp to maintain daytime temp.s around 85-90°F is needed (platform should dry completely for plastron health). Note: Small enclosures (i.e.: 10 to 20 gallon tanks) are easily overheated by basking bulbs, so monitor temp.s closely. We recommend also using UV-B lighting since UV-B provides the means to convert a precursor to Vitamin D₃ in the skin, used to process calcium (& lets them auto-regulate Vit. D₃ levels, which dietary Vit. D₃ doesn't), & recommend ReptiSun 5.0 or 10.0 tube fluorescents for the beginner. A submersible heater is recommended to keep water temp.s in the proper range (turtles are rough & at risk to get burned; use a Tronic heater guard or a home-made version on glass heaters, or a steel heater to prevent breakage). Note: Always unplug the heater before lowering the water level; they get dangerously hot very fast in air. Northern Maps are excellent swimmers and adults should have water as deep as possible without permitting escape (at least equal to SCL). Aquatic substrates are optional, ranging from a bare bottom (easiest to clean during water changes) to sand, river rock or any size gravel. There are reports of rare cases in aquatic turtles (not necessarily this species) of G.I. obstruction or intestinal prolapse due to ingesting gravel, so some keepers use River Rock too large to swallow. We recommend you provide submerged driftwood or other means for the turtle to rest near the surface, especially juveniles (recall they favor brush piles in the wild; a bland, empty tank is not good). It's hotly debated whether leaving the tank lights on 24/7 is problematic vs. turning them off at night. Some other animals have internal circadian rhythms influenced by 'photo-period' (day length), & in nature they experience day & night, so we recommend using a timer for a consistent day/night cycle with 'lights on' ~ 12 hours/day (the convenience of a timer will surprise you). Aquatic turtles excrete nitrogen-containing wastes including ammonia, & a powerful filter is needed to convert ammonia to nitrite to nitrate (called 'biofiltration,' which isn't in effect until the filter 'cycles' over ~ 4 to 6 weeks. Add some old biomedia from an established filter to your new one to speed the process). The impact of ammonia & nitrite on turtles aren't yet clear but they can kill fish so we recommend a filter rated for at least double the enclosure size (i.e.: a FilStar XP3 rated for a 175 gallon tank does well on a 75 gallon) to ensure rapid breakdown. Nitrates & other dissolved wastes are kept dilute via water changes; you've got a lot of choice here. A 25% water change weekly in a sparsely populated tank may be okay. A large (50 - 90%) water change every 2 to 3 weeks using a Python system to gravel vacuum, remove old water & replace with new is easier - the sudden shift in water temp. & pH shouldn't hurt the turtle but may kill delicate fish. We've had reports of turtles acting like chlorine irritated their eyes, & chlorine could damage your filter's beneficial biomedia bacteria, so we recommend you use a dechlorinator (that also handles chloramines, since they're much more stable over time & some cities are switching to them).

RECOMMENDED ENCLOSURE

Barring the larger exceptions, single adult male Northern Maps could do okay in a 75 gallon aquarium. Single large adult females need a minimum of a 125 gallon tank. This allows them decent room (quality of life) in addition to plenty of water to assist in good health and filtration. Basking areas can be made of dirt, sand, gravel, smooth rocks or flat rocks, driftwood or anything that will support their weight and is non-abrasive. Adult Northern Maps can be kept in smaller enclosures, but the setups tend to resemble cells with inmates.

For adding additional Northern Maps we recommend you increase the size of the tank accordingly by half for each (actually 2 can share a habitat suitable for one, but males are apt to sexually harass females & may require separate housing). Large stock tanks are cheap, sturdy alternatives to glass and acrylic aquariums.

Hatchlings can start out in a 20 gallon long glass aquarium if need be, although the total setup cost will likely run ~ $350 (tank, stand, hood, UV-B bulb, basking lamp & bulb, filter, submersible heater, substrate) & a 75 gallon setup ~ $1,000 or a 125 gallon setup ~ $1,600 (see How To Set Up Your First Turtle Enclosure).

You'll need a sizeable enclosure, basking lamp & bulb, UV-B lighting (typically a fluorescent hood & UV-B bulb), basking platform, submersible heater (or 2; you want 3-5 watts/gallon), powerful filters (rated for at least double maximum tank size) & a substate (if you wish). A sample adult setup for females (prices rough estimates, high to reflect tax &/or shipping, but are consistent with online vendors (except tank combo. & stand). Buying the whole system local retail will cost a lot more):

Example Glass Aquarium Setup for up to 2 Northern Maps, sized to accommodate adult females.
1.) 125 Gallon glass aquarium combo. with fluorescent light hood & glass canopy:	~ $650.
2.) Oak Stand Cabinet:	~ $450.
3.) Black Clamp Lamp with Ceramic/Porcelin socket for heat bulb:	~ $20.
4.) 2 200 watt Stainless Steel submersible heaters:	~ $40.
5.) 2 Rena FilStar XP3 Canister Filters with additional purchase of biomedia:	~ $200.
6.) Large Turtle Ramp (for female RES or big males plan to build your own platform):	~ $30.
7.) Digital Thermometer:	~ $10.
8.) 1 Can ReptoMin Aquatic Turtle Food:	~ $10.
9.) Python System for water changes:	~ $30.
10.) 3 Bags of 'River Pebbles' from Lowe's (cheaper than pet store gravel):	~ $25.
11.) 100 watt Ceramic Heat Emitter (more expensive but longer lasting than light bulbs)	~ $25.
12.) 1 ReptiSun 10.0 tube fluorescent bulb for UV-B: (Use in place of one of the fluorescent bulbs that came with your tank combo. with this bulb, nearest the basking platform).	~ $25.
Total:	~ $1,500.

Note: This would make a fine setup for 1 or 2 females & could serve as a community tank with fish or a few other turtles (i.e.: stinkpot, southern or midland painted), etc... A 75 gallon setup for a couple of males would be a good deal cheaper.

Budget Options: use a pond filter (noisier but cheaper & good mechanical filtration for water clarity), a single 300 watt stainless steel heater (no fall back if one fails), build your own basking platform, use a regular 100 watt light bulb for basking heat & a large stock tank (warning: stock tanks look 'smaller' for their volume than glass aquariums & you can't see through the walls. A 140 gallon Tuff Stuff stock tank seems smaller than a 125 gallon glass aquarium).

Note: While not as common a safety practice as it should be, we recommend using a Ground Fault Circuit Interrupter. Using electrical equipment around water entails some risk & even a GFCI can't eliminate that completely, but it may help.

WATER DEPTH

Northern Map Turtles are fine swimmers. In the wild, hatchlings tend toward shallower water habitat (particularly around brush piles), and adults more to deeper water. For hatchlings, I personally recommend relatively shallow water (4 to 6 inches, you can go deeper after they have gained more strength.) with plenty of structure to rest on should they tire of swimming. Older juveniles and adults can be housed in much deeper water as long as a submerged rest area is provided. They require a haul out area/basking platform, which should be large enough to offer both a warmer end nearer the heat lamp & a cooler end for resting without heating up.

COMMUNITY HABITAT

Northern Maps make decent community inhabitants with other similar-sized species from the same region, provided that adequate space is given. Do not mix with snappers & be careful mixing with softshells (mainly that the softies don't get scratched up or their noses bitten). Males may sexually harass females & thus be incompatible. Aggressive feeders may out-compete some tank mates (i.e.: musk turtles) so take care to insure everyone eats well. Larger maps have fairly powerful jaws and can potentially injure smaller turtles (i.e.: biting hunks out of the shells of hatchlings, permanently disfiguring or killing them), so only turtles of comparable size are recommended (exception: adult musk turtles such as stinkpots & razorbacks can be kept with maps if everyone gets along).

Note: Northern Maps are not very abundant in the U.S. turtle market & while not expensive seem to sell fairly quickly so they're a reasonable choice to breed if you wish.

This info. is modified from Timdog's technique for breeding Midland Painted Turtles. Tim has kept Northern Maps & incubated Northern Map eggs but not bred his own Northerns. This technique should also work for Common Maps, although Northern Maps may use a rapid head bobbing (rather than fore-claw flutter) to show interest in females). Per Tim:

Northern Map turtles can be bred in captivity. Tim has heard Northern Maps can be tough to breed indoors & you may need to induce breeding behavior via a 90 day hibernation or 'cool down' period. Courtship involves the male sniffing the female's face & using a head-bobbing maneuver to entice the female. Eventually the female may give into his advances and allow him to mount. If need be you may introduce more than one male (to induce competitive behavior) &/or separate the sexes ~ 4 weeks then reintroduce them to stimulate interest in mating. Two or three weeks after copulation the female should be palpitated for eggs (you can do this by gently inserting a finger between carapace & plastron in front of the rear legs. If she is indeed gravid, you will feel several lumps. At this time provide a sizeable nesting area.

Provide an area of damp sandy, loamy soil 12 - 14" deep. The female will search out a suitable area, possibly digging several ‘test nests’ before choosing a spot to lay. The egg chamber is constructed with alternating scoops of the hind feet. If laying is not witnessed, look for recently disturbed ground and carefully look in that area for eggs. If you have doubts that she has laid eggs, just palpitate her again. She should feel considerably lighter.

Tim's observations of wild Northern Maps are that sandy areas with sparse vegetation are preferred over rocky, hard, clay-based substrates. All nests he's found were laid well above the high-water line but almost always within 100 years of the water, in wide open areas receiving sunlight most of the day.

Wild female Northern Maps from Niangua River in Missouri averaged 10.1 eggs/clutch (range 6-15), & data indicated they laid at least 2 clutches/year (maybe even 3) (White and Moll, 1991)¹⁵.

This is Timdog's technique for incubating North American turtle eggs shown to work for common snappers, common map turtles, Alabama map turtles, painted turtles, musk turtles, softshells & box turtles; it should work well for Red-eared Sliders. Per Tim:

The easiest way I have found to incubate the eggs is to place them in a plastic container with a mixture of peat moss and cactus succulent potting soil or vermiculite (punch a few drainage holes in the bottom of the container with the eggs to prevent moisture from pooling). The eggs should be buried in the substrate with only the top of the egg exposed (mark the top with a pencil in case they need to be moved for candling) The container is then placed on a wire rack inside of a cooler with a few inches of water at the bottom. Heat is provided by an aquarium heater set to 78º to 83º F. This will also maintain a humidity level of 75 to 85 % (Humidity is important; for example, Midland Painted Turtle eggs are leathery and will dent or collapse and die if relative humidity is not maintained at 80% or better.) Incubation at 83º F will produce hatchlings in as little as 50 days. 78º F, 55 to 60 days. It is important to keep the substrate choice slightly moist, not damp and the eggs should be covered by a layer of moss or a slanted lid to prevent condensation from dripping directly on the eggs. In the last 2 weeks of incubation watch moisture levels closely, too much and the egg can rupture prematurely. When the eggs start hatching you can help the turtle hatch if it appears to be having trouble doing so on its own. The neonate will slice the egg with the egg tooth and use its front legs to peel back the rest of the egg. If the front legs are all that emerges you can gently remove the shell in front of the neonates head. This can prevent drowning in the egg. The Neonate will remain in the egg for several hours or up to 2 days before absorbing enough of the yolk sac to emerge. It will then promptly bury itself in the substrate to finish absorbing the yolk (they should be then placed in another container inside the incubator to avoid them disturbing any unhatched eggs. They can be introduced to very shallow water as soon as the yolk sac is almost completely healed. They will accept food within 5 to 6 days of absorbing the yolk.

Tim's estimate of 50 to 60 days is roughly accurate for midland painted eggs incubated artificially but may vary a bit for maps; in Turtles of the World (Page 218)¹⁶ the authors report wild hatchlings emerge after about 75 days. The cooler the temp.s the longer they take to incubate. Northern Map Turtles exhibit temperature-dependent sex determination, & turtles produced by specifically incubating to produce an all-male or all-female clutch are called 'temp. sexed,' although breeders hardly ever offer temp.-sexed Northern Map hatchlings.

Mainly males are produced when incubation temps are maintained at 77° F (25° C) (Bull and Vogt, 1979)¹³, (Ewert and Nelson, 1991)¹⁴.

Females are produced at a maintained temp. of 86° F (30° C) or higher. (Bull and Vogt, 1979)¹³, (Ewert and Nelson, 1991)¹⁴.

Mixed genders produced between at intermediate temp.s.

Hatchling a few weeks old.

Photo by Richard Lunsford.

ENCLOSURE

A hatchling's captive habitat should mimic that of an adult. The requirements are the same pertaining to lighting, heat, basking (albeit perhaps not quite so hot, & be sure that basking lamp doesn't overheat the water!) and water depth. Some keepers worry that their turtle might drown in a deep water aquarium and opt to give the hatchling a shallow habitat. That is inaccurate. Hatchlings - even fresh day old hatchlings - can tolerate deep water. However, in the wild smaller Northern Maps tend toward shallower water than adults, so provide plenty of structure (i.e.: driftwood, live or artificial plants, etc...) for stability, hiding and climbing. The temperature range for hatchlings and yearlings onward is a bit different due to shallower waters being warmer in nature & to optimize immune system function (conventional wisdom is turtle immune systems work better at warmer temp.s, & hatchlings are more delicate than older turtles). Hatchlings and yearlings should be maintained in the same range as the daytime and basking temperatures listed above, but their water temps should be kept between 78° and 80°F. Wild Northern Maps use the UV-B content of natural sunlight shining on their skin to convert a precursor in the blood into Vit. D₃. This process is self-regulating to prevent overdosing. Dietary Vit. D₃ supplementation is not self-regulating & gross over-supplementation can cause toxic effects. Therefore we recommend providing brand name UV-B lighting (i.e.: ReptiSun 5.0 & 10.0 tube fluorescent bulbs) & a diet containing at least some Vit. D₃ (most good brand commercial aquatic turtle diets do).

DIET

Covered under 'Recommended Feeding Schedule' in the adult section. Northern Map Turtles vary in growth rate. You're looking to see yearling SCL ~ 2 to 3.5", & a smooth carapace without raised, bumpy scutes or concentric rings on the scutes (a few slight 'ripple' waves near the scute bottom are okay). You can feed larger volumes of natural prey items (i.e.: feeder insects) than commercial turtle pellets since the latter are nutritionally 'denser' due to much lower moisture content. However, if you feed a hatchling exclusively on feeder insects (i.e.: crickets & mealworms) without vitamin supplements & keep it indoors without UV-B lighting, it'll be calcium & Vit. D₃ deficient, that soft hatchling shell won't firm up, the turtle will develop metabolic bone disease & pyramiding of the shell, & it'll eventually die from bad care. We strongly recommend a good brand name commercial food comprise at least 50% of the carnivorous portion of the diet, & that you provide UV-B lighting.

Activity Cycle: Northern Map Turtles are a diurnal species and their activity varies by climate. In nature during cooler seasons they spend more time basking to warm up than during the heat of summer. In captive enclosures some common basking turtles seldom bask if the water is quite warm (i.e.: 80-82º). Captive basking turtles vary as individuals; many sleep under water, but some may sleep on a basking platform.

Map turtles don't wander on land as much as Red-eared Sliders do. Due to their inability to close the shell like a box turtle they are vulnerable to raccoons & other predators. Dogs can chew through turtle shell fairly quickly.

Hibernation occurs throughout their range.

In The Amphibians and Reptiles of Arkansas (pages 222-223)² authors note like all map turtles Northerns are hard to trap because they don't readily respond to bait. Note: There are other ways to trap them (i.e.: for research purposes).

Personability & Issues Interacting with Humans:

Northern Map Turtles make good pets if you can meet their care needs. The need for a large enclosure is the main hurdle many keepers face. Juveniles should acclimate shortly to a human presence, associate the human with food & vigorously beg for food (which can get annoying). While map turtles have a reputation for nervousness/skittishness, individuals vary & yours might become quite personable.

Wild Northern Map Turtles are frightened of humans & dive in from basking sites quickly. If handled they withdraw into the shell; some may void the bladder & offer to bite. Most won't lash out (as common snappers do) but a finger put closely in front of the face may be bitten hard.

Northern Map Turtles, like other reptiles & a number of non-reptile pets (including dogs & cats), can transmit Salmonella bacteria, which can cause the disease Salmonellosis in humans. Research this condition, become familiar with it & practice hygienic pet care to minimize risk of contracting it. Always wash your hands with a bactericidal hand sanitizer after contacting any reptile, its enclosure, water or items that have contact with same. If a Python water-changing system will only fit your kitchen sink, not your bathroom sink, you must decide whether to use it & what precautions to take (i.e.: disinfecting the sink with bleach after a water change). The same concern is raised if you wash tank accessories (i.e.: clean the filter) in the sink. Austin's Turtle Page, TurtleForum.com & our ITTN affiliates are not medical sites & do not offer professional medical advice regarding Salmonellosis, risk, diagnosis or treatment although individual community members may express good faith lay opinions & their practices. Ultimately, the responsibility for decisions regarding disease risk management rests with the pet owner. See our Useful Online Resources section below to start learning.

Basking:

Northern Map Turtles bask extensively in captivity. As long as there are no signs of obvious health problems (swollen eyes, runny nose or gaping) and your turtle is active, eating & willing & able to enter the water, swim & submerge, frequent & extended basking is normal.

1.) Austin's Turtle Page - our central information base & teaching site for general aquatic turtle care.

2.) Designing Your First Turtle Enclosure - our ATP article on planning a freshwater aquatic turtle setup, including different size classes, budget options & cost.

3.) Crash Course in Baby Water Turtle Care - A concise setup guide for people who have a hatchling water turtle (including maps) in hand & need to get a starter setup together right now.

4.) Rubbermaid Tubs vs. Aquariums as Enclosures - exploring a budget option for people keeping juvenile on up to smaller adult male Common Maps.

5.) Choosing Your First Turtle - please read thoroughly before you buy. Common Map turtles aren't the best starter turtle for everyone, & there are excellent options such as male Texas maps, male southern painted turtles & stinkpots who stay smaller & have similar care requirements.

6.) Concise Guide to Choosing North American Turtles as Pets - a 'window shoppers' guide' to what's out there, with photo.s & basic facts.

7.) Where to Get a Turtle - an article introducing you to the market & how to get what you're after.

8.) Filtration - get up to speed on mechanical, biological & chemical filtration & the popular aquarium filter models keepers are using. Also check out ATP Product Reviews - Filters, and our Comparison of the FilStar XP3, Fluval 404 & Eheim Pro II 2028 large canister filters.

9.) ATP Guide to UV-B Lighting - if you want to really get into this complex topic.

10.) What to Keep with Turtles - a review of animals & fish you might try with your turtle.

11.) The Basking Spot Page - a multi-page article at our ITTN affiliate ATP Habitats, discussing both commercial basking platform products & ways to make your own.

12.) Pet Warehouse - a reputable major online superstore for pet supplies. You can often get higher priced items like canister filters, ReptiSun 5.0 & 10.0 UV-B tube bulbs & ceramic heat emitters at drastic savings over retail.

13.) That Pet Place - a reputable major online superstore for pet supplies. You can often get higher priced items like canister filters, ReptiSun 5.0 & 10.0 UV-B tube bulbs & ceramic heat emitters at drastic savings over retail.

14.) Big Al's Online - a reputable major online superstore for pet supplies. You can often get higher priced items like canister filters at drastic savings over retail.

15.) Reptile Direct - a smaller yet reputable online pet store widely popular for rock bottom prices.

16.) Herp Supplies - A smaller yet reputable online pet store I've found useful for surprising odds & ends like a 2 foot pair of tweezers, backgrounds, steel heaters & other things.

17.) The Center for Disease Control (CDC) Disease Information Page on Salmonellosis. This link opens the General Info. Page, but click on the Technical Info. & Additional Info. tabs for more information.

18.) The Center for Disease Control (CDC) Salmonella (Salmonellosis) Infection and Animals Fact Page.

19.) Pet Owners Beware: Reptiles Can Cause Salmonella Infections - WebMD article by Andrea Braslavsky from Nov. 10'th, 1999. Includes specific CDC recommendations.

20.) World Chelonian Trust's Map Turtle Care Sheet - our ITTN affiliate's general care guide for map turtles.

21.) Map Turtles of the United States. David Kirkpatrick, Ph.D. Reptile & Amphibian Magazine, Nov/Dec. 1993, pg 6-17.

22.) Graptemys.com - our ITTN affiliate devoted to map Turtles. Here's the Northern Map page. Site owner Chris Lechowicz.

23.) ATP World of Turtles Northern Map Photo Gallery - a collection of photo.s, both captive & wild.

BIBLIOGRAPHY

1.) Turtles of The United States and Canada. Carl H. Ernst, Jeffrey E. Lovich and Roger W. Barbour. Smithsonian Institution Press, Washington and London. ©1994. (Possibly the preeminent natural history text of North American turtles – not a care guide but very highly recommended).

3.) A Field Guide to Reptiles and Amphibians of Eastern and Central North America. 3'rd Ed., Expanded. Roger Conant & Joseph T. Collins. Houghton Mifflin Company. South New York, New York. (Probably the most prestigious field guide on the topic covering this large area. Not a care guide, but highly recommended).

6.) Fuselier, L., and D. Edds. 1994. Habitat partitioning among three sympatric species of map turtles, Genus Graptemys. J. Herpetol. 28:154-158.

7.) Pluto, T. G. and E. D. Bellis. 1986. Habitat utilization by the turtle Graptemys geographica, along a river. J. Herpetol. 20:22-31. Cited in Turtles of The United States and Canada¹.

8.) Pluto, T. G. and E. D. Bellis. 1988. Seasonal and annual movements of riverine map turtles, Graptemys geographica, along a river. J. Herpetol. 22:152-158. Cited in Turtles of The United States and Canada¹.

9.) Ernst, C. H. and R. W. Barbour. 1972. Turtles of the United States. University of Kentucky Press, Lexington. 347 pp.

10.) Penn, G. H. 1950. Utilization of crawfishes by cold-blooded vertebrates in the eastern United States. Amer. Midl. Natur. 44:643-658. Cited in Turtles of The United States and Canada¹.

11.) White, D., Jr. and D. Moll. 1992. Restricted diet of the common map turtle Graptemys geographica in a Missouri stream. South-west. Natur. 37:317-318. Cited in Turtles of The United States and Canada¹.

12.) Vogt, R. C. 1981. Food partitioning in three sympatric species of map turtle, genus Graptemys (Testudinata, Emydidae). Amer. Midl. Natur. 105:102-111. Cited in Turtles of The United States and Canada¹.

13.) Bull, J. J., and R. C. Vogt. 1979. Temperature-dependent sex determination in turtles. Science 206:1186-1188. Cited in Turtles of The United States and Canada¹.

14.) Ewert, M. A., and C. E. Nelson, 1991. Sex determination in turtles: Diverse patterns and some possible adaptive values. Copeia 1991:50-69. Cited in Turtles of The United States and Canada¹.

15.) White, D., Jr. and D. Moll. 1991. Clutch size and annual reproductive potential of the turtle Graptemys geographica in a Missouri stream. J. Herpetol. 25:493-494. Cited in Turtles of The United States and Canada¹.

17.) Cox, William A., Steven T. Wyatt, Walter E. Wilhelm and Ken R. Marion. (1988). Infection of the Turtle Sternotherus minor, by the Lung Fluke, Heronimus mollis: Incidence of Infection and Correlations to Host Life History and Ecology in a Florida Spring. Journal of Herpetology. Vol. 22, Number 4, pp. 488-490.

18.) Ulmer, M. J. and S. C. Sommer. (1957). Development of sporocysts of the turtle lung fluke, Heronimus chelydrae MacCallum (Trematoda: Heronimidae). Proc. Iowa Acad. Sci. 64:601-613. Cited by 10.), above.

19.) Crandall, R. B. (1960). The life history and affinities of the turtle lung fluke, Heronimus chelydrae MacCallum, 1902. J. Parasit. 46:289-307. Cited by 10.), above.

20.) Ulmer, M.J. (1960). Physa sayii, a new intermediate host for the lung fluke Heronimus chelydrae (Trematoda: Heronimidae). J. Parasit. 45:813-814. Cited by 10.), above.

Special Credits:

Special thanks to Chris Lechowicz (Graptemys), Cris Hagen (Batagur), Wendy (Turdle), Paul V. (Chelidman), Thomas Coy & other photo contributors for assistance with information & resources to make this care sheet possible.