Order Anura: Frogs And Toads
Description: Frogs and toads (order Anura) are divided into 16 families, with a total of some 2700 species worldwide. Adult frogs and toads lack tails, have well-developed front legs and even larger hind legs adapted for hopping and leaping. Most have a well-developed ear and a voice used to attract mates, drive off intruders, and warn of their presence.
Anurans in our area are members of the following families: Bufonidae (toads), Hylidae (treefrogs and chorus frogs), and Ranidae (true frogs). All require some sort of open water?such as a pond or calm shallow part of a stream?to breed. Eggs are laid in clusters or strings encased in a jellylike substance until larval tadpoles emerge.
Tadpoles go through many stages of growth and development until they take on the appearance of adult frogs. While tadpoles are herbivores, feeding on algae and aquatic vegetation, adult frogs are carnivorous. They possess large mouths and a tongue attached to the front of the lower jaw that flips out to capture prey which is swallowed whole.
Family Bufonidae, True Toads
Key Characteristics: Large, kidney-shaped parotoid glands; large spots on back usually encircle 1-3 warts; enlarged warts on lower leg.
Key Characteristics: Parotoid gland is oblong in shape; large dark spots on back encircle 1?6 warts; no enlarged warts on lower leg.
Habitat: Streams, ponds, and lakes; often encountered a long distance from water. Typically in lowland areas where the soil is sandy or well-drained.
Family Hylidae, New World Tree Frogs
Key Characteristics: Small with a pointed snout; warty-skinned; a dark triangle, pointed backwards, usually evident between the eyes.
Habitat: Can be found in virtually any wet habitat, but most common in open areas surrounding lakes, ponds, rivers, swamps, and marshes.
Habitat: Most common in large forested tracts. Avoids small isolated forest patches except when adjacent to a stream or other permanent source of water.
Habitat: They are most abundant in extensive tracts of wet forest, but can be found in oldfields, open marshes, and other habitats. They can often be found hopping through leaf litter or climbing in grass clumps or other vegetation, especially during rainy or wet weather.
Habitat: Found in marshes, prairies, agricultural fields, and other open habitats, and occasionally in woods and forested swamps. Essentially a prairie animal that is tolerant of agriculture and thrives in intensively-farmed landscapes.
Family Ranidae, Riparian Frogs And True Frogs
Key Characteristics: Dorsal lateral ridge wraps around tympanum (does not run down back); snout blunt.
Habitat: Inhabits virtually any permanent body of water.
Habitat: Ponds, lakes, streams, swamps, and other permanent or semi-permanent water bodies. They are more tolerant of sparsely-vegetated habitats than are Bullfrogs.
Habitat: Ponds, creeks, and marshes in northern Illinois; in central and western parts of the state found in cold springs and rocky, high-gradient streams (often in cave streams along the Mississippi river bluffs). Avoids warm sluggish water.
Key Characteristics: Dark mask on side of head extending backward from the eye; tan to black in coloration; unspotted back
Habitat: Restricted to fairly large tracts of mesic coniferous, mixed, or deciduous forest where vernal pools are present.
Family Scaphiopodidae, North American Spadefoots
Habitat: Most abundant in open fields with loose, sandy soil. Occasionally in wooded areas.