(Agassiz, 1857)
Ornate box turtle
Recognition
The carapace (to 14 cm) is generally round or oval and high domed; the highest point is directly above or anterior to the plastral hinge. It is without posterior serrations and is flattened dorsally. Essentially the carapace is keelless, as only rarely does a weakly developed medial keel occur on the posterior half of the 3rd and anterior half of the 4th vertebrals. The 1st vertebral is elevated at a low angle (45° or less), and the 1st marginal usually is irregularly oval or triangular. Usually all vertebrals are broader than long. The carapace is dark brown to reddish brown, often with a yellow middorsal stripe; each scute shows radiating yellowish lines. The plastron is often as long as or longer than the carapace, and its lateral margin is not usually indented. The plastral formula is: an > abd >< gul > fem >< pect > hum; the hindlobe lacks a posterior notch. No bridge is present, and there is usually no axillary scute (if present it is at the 5th marginal). The plastron has a pattern of radiating lines on each scute. The head is small to moderate in size with a nonprotruding snout and an unnotched upper jaw. It is brown to green with yellow spots dorsally and yellow jaws. Other skin is dark brown with some yellow spotting. The tail may have a yellow dorsal stripe. There usually are four toes on each hind foot, rarely only three.
The karyotype is 2n = 50: 26 macrochromosomes (16 metacentric, 6 submetacentric, and 4 telocentric) and 24 microchromosomes (Stock, 1972; Bickham and Baker, 1976a; Killebrew, 1977a; Bickham, 1981).
In adult males the iris is red; in females it is yellowish brown. In males the first toe on the hind foot is thickened, widened, and turned in. The hindlobe of the plastron is slightly concave in males, flat or convex in females. Females grow larger than males.
Distribution
Terrapene ornata ranges from Illinois, Iowa, South Dakota, and eastern Wyoming south to southwestern Louisiana, Texas, New Mexico, southeastern Arizona, and Sonora and Chihuahua, Mexico. It also occurs locally in northwestern Indiana, and there is a record from Wisconsin.
Geographic Variation
Two subspecies are recognized. The ornate box turtle Terrapene ornata ornata (Agassiz, 1857) ranges from western Indiana and eastern Wyoming south to southwestern Louisiana and eastern New Mexico. It is distinguished by the five to eight radiating lines on the 2nd pleural and by its generally dark appearance. The desert box turtle T. o. luteola Smith and Ramsey, 1952 ranges from the Trans-Pecos region of Texas and southeastern Arizona south into northeastern Sonora and northern Chihuahua, Mexico. It has 11-14 radiating lines on the 2nd pleural and is generally yellowish in color. Shells of old individuals often lose their pattern and become uniformly pale green or straw colored; this pigment loss does not occur in T. o. ornata.
Habitat
Terrapene o. ornata is a "prairie" turtle, inhabiting treeless plains and gently rolling country with grass and scattered low brush as the dominant vegetation. T. o. luteola, however, often lives in more arid semi- to desert habitats, where individuals select microhabitats with lower soil temperatures, higher ambient temperatures, and lower humidity levels (Nieuwolt, 1996).
Natural History
Sexual maturity is more closely correlated with size than age. In Kansas, males mature at 10.0-10.9 cm plastron length at ages 8-9 years, and females are mature at 11.0-12.9 cm at ages 10-11 (Legler, 1960a). Blair (1976) reported Texas males matured at seven years, but that females first reached maturity at eight years. The smallest gravid female in New Mexico examined by Nieuwolt-Dacany (1997) had a carapace length of 10.7 cm. The spermatogenic cycle begins in May in all parts of the range and reaches its peak in September, and is completed in October when sperm pass into the epididymides, where they are stored over the winter; thus females are inseminated with sperm produced the previous year. The ovarian cycle begins in July after ovulation, and continues until the next spring. Follicular growth is rapid during the period from spring emergence to ovulation. Large follicles remaining after ovulation often represent eggs that will be possibly laid later the same season.
Courtship and mating occur most commonly in spring, soon after emergence from hibernation but sometimes in summer. Brumwell (1940) described mating in T. o. ornata. A male pursued a female for nearly 30 min, first nudging the margins of her shell and later approaching rapidly from the rear and hurling himself on her back while emitting a stream of liquid from each nostril. Presumably the liquid was water: both turtles had imbibed in a pond just before courtship began. After the male had achieved intromission the pair remained in coitus for 30 min; however, the act may last as long as 2 h. In another instance Brumwell saw four males pursuing a single female; they exhibited the same nudging and lunging behavior. Males that attempted to mount other males were repelled by defensive snapping. The female, too, snapped at some of the males that tried to mount her. One male was finally successful and thereafter was unmolested by the other males. In the several matings that Legler (1960b) observed, the male, after mounting the female, gripped her just beneath her legs or on the skin of the gluteal region with the first claws of his hind feet and used the remaining three claws to grip the posterior edges of her plastron. In most instances she secured his legs by hooking her own around them. This coital position differs from that of T. carolina, at least in the position of the male's legs.
Nesting extends from early May to mid-July and is most frequent in June. However, Ernst's captive females, which remain active all year, have laid as early as mid-March and as late as August. About 33% of females lay a second clutch in late June or early July (Legler, 1960a). Nesting sites that are open, well-drained, and have a soft substrate are preferred. The nests are flask shaped and 50-60 mm deep. Females have a much larger pelvic aperture than males, presumably to aid in egg passage (Long and Rose, 1989), and pelvic width is correlated with egg width (Nieuwolt-Dacanay, 1997).
Clutch size ranges from one to eight; four to six eggs are usual, and the number of eggs laid per clutch is positively correlated with female body size (Nieuwolt-Dacanay, 1997). T. o. ornata lay larger clutches (mean 3.5 eggs in Wisconsin, Doroff and Keith, 1990; mean 4.7 eggs in Kansas, Legler, 1960a) than T. o. luteola (mean 2.5 eggs in New Mexico; Nieuwolt-Dacanay, 1997). Spring rains may increase the number of females ovipositing in summer, and in years with dry springs females may not nest at all (Nieuwolt-Dacanay, 1997). The ellipsoidal eggs have finely granulated but somewhat brittle white shells (21-41 x 20-26 mm). Natural incubation lasts about 70 days.
The almost round hatchlings are approximately 30 mm in carapace length. Their carapace is dark brown to black, with yellow spots on the scutes and a yellow dorsal stripe along the vertebrals. The plastron is yellow to cream colored, with a large, dark central blotch; the hinge is not yet developed. The hinge becomes functional in the fourth year.
Under natural conditions T. ornata is chiefly carnivorous; captives, however, eat a variety of vegetable matter as well as meat. Insects (chiefly beetles, caterpillars, and grasshoppers) account for approximately 90% of their natural food. Dung beetles constitute the most important staple element of the diet: the disturbance of piles of dung by turtles in the course of their foraging is a characteristic sign of T. ornata. Insects form the bulk of the diet most of the year, but certain other foods (for example, mulberries) are eaten in quantity when especially abundant, sometimes to the exclusion of other foods. T. ornata also eats carrion.
The daily cycle of activity of T. ornata consists of periods of basking, foraging, and rest that vary in length in keeping with environmental conditions. These turtles emerge from their nighttime burrows, forms, or other places of concealment soon after dawn and ordinarily bask for at least a few minutes before beginning to forage. Although foraging sometimes continues in shady spots throughout the day, it usually ceases between midmorning and noon, when the turtles seek shelter. They remain under cover until mid afternoon or late afternoon, when they again become active. Activity of all except nesting females ceases at dusk. As temperatures rise in summer the period of midday quiescence is lengthened and the turtles sometimes spend the warmest hours in pools of water. At least in the southwestern part of its range, activity of T. ornata seems to be largely controlled by rainfall: it becomes specially active during and after thunderstorms.
Ornate box turtles begin to enter hibernation in October; by the end of November most or all of them are underground. In Kansas, autumn activity is characterized by movement into ravines and other low places and into wooded strips along fields or small streams (Legler, 1960b), places good for basking and burrowing as well as for protection from the wind. The turtles often use animal burrows along the banks of a ravine for temporary shelter, and the overhanging sod at the edge of the ravine provides cover beneath which the turtles can easily dig. Emergence is in March or April.
IUCN Red List Status (1996)
Lower risk: near threatened. While Terrapene ornata remains locally abundant in some parts of its range, it has been eliminated from vast areas that have been undergone agricultural conversion from prairie to intensive cultivation. This turtle seems to be largely compatible with the use of grasslands for light to moderate grazing of livestock, but usually disappears with the introduction of irrigated crops such as corn. Ornate box turtles have also been locally impacted by mass collection for the commercial pet trade. Such exploitation is ill advised from both conservation and humanitarian perspectives, since this turtle rarely survives for long when kept as a pet in humid regions outside of its natural range.