The plains leopard frog is medium-sized, with a light tan ground color and numerous rounded spots on the back. The head is wide and blunt, giving this species a stocky appearance. There is a distinct light line along the upper jaw. A white spot is almost always present on the tympanum (rounded ear spot). The ridge of skin along each side of the back is broken near the groin and a small hind section of it is usually displaced upward (further toward the midline). The numerous brown or green-brown spots on the back and legs are usually circular and uniform in shape. A dark spot is usually present on the snout. The belly is white with pale yellow near the groin and lower inner thighs.
The call of male plains leopard frogs is a rapid series of guttural “chuck-chuck-chuck” sounds at a pulse rate of 3 per second.
Similar species: Missouri’s two other leopard frogs and the pickerel frog all lack the distinctively broken and displaced skin ridges along the sides of the back, and by the absence of distinct white rings around each spot on the back.
In a number of Missouri counties, the plains leopard frog occurs within the same geographic range as the southern leopard frog, and in our northwestern counties, it can occur in the same places as the northern leopard frog. Hybridization with these two species may occur, usually where habitats have been altered due to human activity. When a breeding habitat is changed, the environmental barriers that would normally isolate species during their breeding season are lost, and hybridization may occur. The hybrid offspring usually show a blend of their parent species' characteristics and may be tricky to identify.
Missouri has eight members of the true frog family. These are typically medium- to large-sized, have long legs, smooth skin, and well-developed webbing between the hind toes. Another common characteristic is a glandular fold or ridge of skin along each side of the back (these are called dorsolateral folds).
Adult length (snout to vent): 2 to 3¾ inches; occasionally to 4½ inches.
Occurs throughout most of Missouri, including the Bootheel, but rarely present in the Ozarks.
Habitat and Conservation
Active from March to October. Primarily a Great Plains species. In Missouri, the plains leopard frog lives in grasslands, including former prairie regions and associated river floodplains of northern, central, and western Missouri, as well as the sand prairie and river floodplains in the Bootheel. It uses a variety of aquatic habitats, including water-filled ditches, farm ponds, river sloughs, small streams, temporary pools, and marshes.
During winter, these frogs retreat into the mud and dead leaves at the bottom of ponds and streams.
In the summer, individuals are active in and around wet areas, but they will venture into grassy areas well away from water.
This species can be quite abundant in favorable habitat. Hundreds have been seen on dirt roads adjacent to wetland marshes in Holt County during the night, presumably foraging for prey.
The plains leopard frog eats a variety of small invertebrates, such as flies, beetles, spiders, worms, crickets, and grasshoppers.
Taxonomy: The true frog family (Ranidae) is the largest and most widespread family of frogs. It contains 365 species in 14 genera and probably originated in Africa. Representatives of this cosmopolitan family occur on every major land mass except New Zealand, Antarctica, most oceanic islands, the West Indies, and southern South America. The largest genus in the family in the New World (North and South America) is Lithobates (formerly Rana), with about 50 species. Missouri’s species, formerly in genus Rana, are all in genus Lithobates. As of taxonomic understandings in 2016, the Rana genus is considered restricted to the eastern hemisphere and western North America. In Missouri, the genus Lithobates is represented by eight species.
Breeding in Missouri is generally from mid-April to early June (sometimes as early as mid-March in southeastern Missouri); some years they breed in autumn, too, if the weather is cool and rainy enough. Males gather at a marsh, pond, or temporary pool and begin calling after sunset. Females lay eggs in round or slightly oblong masses that are surrounded by a thin coating of clear, protective jelly. The clusters are attached to submerged stems or branches in shallow water. Each mass can have 4,000–6,500 eggs, which hatch in 2–3 weeks. Tadpoles become froglets in midsummer (about 3 months after egg laying) or may overwinter in the breeding ponds and transform the next spring.
As predators, these amphibians help decrease populations of many insects that are pests to humans. Additionally, their strange, rhythmic calls add to the magic of a Missouri evening.
Missouri’s anglers sometimes use plains leopard frogs as live bait (daily limits apply, however; check current fishing regulations to make sure you’re using them legally).
Frogs are predators that help keep populations of insects and other small animals in balance. They, and especially their eggs, tadpoles, and young froglets, become food for both aquatic and terrestrial predators. This species is known to fall prey to ribbonsnakes and gartersnakes.