PARSLEY FROGS: Pelodytidae

PHYSICAL CHARACTERISTICS

Parsley frogs have little dark green blotches on their backs that look somewhat like pieces of parsley. Many people are familiar with parsley as the small, ruffled leaf that often decorates a plate of food at a restaurant. The frogs are rather thin and somewhat flattened with short, slender forelegs and long back legs. Their backs are brown, light greenish brown, or gray and speckled with small rounded warts. The Caucasus parsley frog, also known as the Caucasian parsley frog or Caucasian mud-diver, may have some red dots on its back. The underside in all three species is whitish to gray. The toes on their front feet are long and thin and have no webbing between them. The even-longer toes on the back feet have only a small amount of webbing. These frogs have large eyes with vertical pupils, a rounded snout, and no obvious eardrum on the side of the head. They are rather small frogs, growing to 1.8 to 2.2 inches (4.5 to 5.5 centimeters) long from snout to rump.

Males and females may be quite similar. In the Caucasus parsley frog, however, the female has a reddish back and lower belly. During mating season, the male parsley frog may develop small, rough pads on the toes of its front feet, on its forelegs, and/or on its chest. The rough spots, called nuptial (NUHP-shul) pads, help the male hold onto the wet and slippery body of the female during mating.

Until the year 2000, scientists thought that two of the three species in this family—the common parsley frog and the Iberian parsley frog—were the same species. The Iberian parsley frog, however, has some slight differences. Additional studies are now needed to find out whether populations that were thought to be common parsley frogs are actually Iberian parsley frogs and how the "new" species is surviving overall. In other research, scientists believe this family once had more than just three species. Based on fossils they have studied, they think the extinct species may actually outnumber the living ones.

Some people group the parsley frogs within the family spadefoot toads, but most scientists believe the parsley frogs should be separated into their own family as they are listed here.

GEOGRAPHIC RANGE

All three species of this family live in Europe and/or western Asia. The species known simply as the parsley frog or common parsley frog is found in southwestern Europe. The Caucasus parsley frog lives in Turkey and other areas near the Caspian Sea. The Iberian parsley frog lives in the southern parts of Portugal and Spain.

HABITAT

Parsley frogs live in various moist places, often near water. Some may live in forests near a stony stream, and others in a meadow near a pond. Tadpoles can survive in somewhat salty water.

DIET

Mostly night-feeders, the parsley frogs eat insects, worms, slugs, and other invertebrates (in-VER-teh-brehts), or animals without backbones.

BEHAVIOR AND REPRODUCTION

By day, parsley frogs take cover under rocks or in the bushes or grass that grow along walls. They leave their hiding places as the sun sets and begin hopping about looking for food. They usually stay fairly close to a body of water. If they feel threatened, they can either use their long, strong legs to leap out of sight on land or into the water, where they are good swimmers. The warts on their skin contain a bad-tasting poison, which is useful if a predator happens to catch and try to eat one.

When fall comes, some of the parsley frogs that live in colder areas prepare for hibernation (high-bur-NAY-shun), which is a state of deep sleep. They may start hibernating as early as September and not become active again until the following March. The Iberian parsley frog, which lives in the warmer climate of southern Spain and southern Portugal, remains active all year long and actually is the most lively in winter, when the cold-climate species are hibernating.

For cold-climate species, mating begins in the spring when warm rains soak the ground. In its much warmer climate, however, the Iberian parsley frog mates from fall to spring and becomes less active in the hot summer months. The males travel to ponds, puddles, and sometimes very slow-flowing streams and start calling. Scientists believe that they may call underwater. To mate, a male climbs onto female's back, and she lays her eggs. A female may lay several dozen eggs at a time and, depending on the species, may lay several hundred over the whole night. Sometimes, they may breed more than once a year, such as spring and fall. The eggs attach to sticks and leaves underwater and eventually hatch into tadpoles. Eggs of the Iberian parsley frog hatch quickly, needing just a week before the tadpoles wiggle out.

Depending on the species of parsley frog and the weather, the tadpoles may change into froglets about two to three months later, may hibernate as tadpoles and make the change the second year, or may hibernate yet again and change into froglets in their third year. Tadpoles hibernate by sinking into the mud at the bottom of their pond or pool of water and remaining there until the spring. Tadpoles that wait longer to change into froglets can grow quite large, sometimes even becoming bigger than the adults. Parsley frogs usually are old enough to have young of their own when they are two to three years old. Only frogs, and not tadpoles, can mate and have young.

BIG BABIES

In some species, such as the parsley frogs, the tadpoles can be larger than the adults. How can this be? The answer is in the tail. As a tadpole changes into a froglet, it absorbs its tail. In other words, the tail disappears into the body. Often, new froglets still have small stumps of tail that have not yet vanished. In most frogs, tadpoles make the change into froglets when they are just a few months old. In parsley frogs and some other types of frogs, however, the tadpoles may not become froglets for one or two years. These especially old tadpoles can grow to be quite large—sometimes nearly twice as big as the adults.

PARSLEY FROGS AND PEOPLE

People rarely keep these frogs as pets, do not eat them as food, and do not collect them for experiments or for making medicines. Since parsley frogs spend their days hidden away, most people never see them. The frogs may still be helpful to humans, however, because they eat insects that some people consider pests.

CONSERVATION STATUS

None of these three species is generally considered to be at risk. However, several countries have listed them as Endangered or Vulnerable. An Endangered species faces a very high risk of extinction in the wild, and a Vulnerable species faces a high risk. In some populations, the number of frogs has dropped quite low. Often, the destruction of habitat is to blame. Sometimes, people drain water from a marsh or stream to turn it into farmland or to build homes or businesses. In addition, the habitat may become dangerous to frogs because of fertilizers and other pollutants that drain from human developments into streams and ponds.

PARSLEY FROG (Pelodytes punctatus): SPECIES ACCOUNT

Physical characteristics: Also known as the common parsley frog or mud-diver, adults of this species are thin, somewhat flattened frogs. They have brown, light brownish green, or gray backs with dark green blotches and have numerous, small warts. The belly and the throat are whitish, and the underside of their legs is yellow-colored. They have a thin, black stripe on each side of the head from the snout, through the middle of the eye, and to the foreleg, as well as dark blotches on the upper lip. Their eyes are large and copper-colored and have vertical pupils. They do not have obvious eardrums showing on the sides of the head. Their forelegs are smaller and thinner than their hind legs, and all four limbs are brown with green blotches. The parsley frog has long toes. The toes on the front feet have no webbing between them, and the toes on the back feet have only a little webbing at the bottom. Adults grow to 1.4 to 1.8 inches (3.5 to 4.5 centimeters) from the tip of the snout to the end of the rump. The tadpole is greenish brown with noticeable dark eyes. It has an oval-shaped head and body and a long tail. Tadpoles can reach 1.6 to 2.6 inches (4 to 6.5 centimeters) long from head to tail before they change into froglets.

Geographic range: The common parsley frog lives in southwestern Europe, including Belgium, Luxembourg, France, Italy, Spain, and Portugal.

Habitat: The common parsley frog lives in many habitats, including forests, shrubby woods, and farmland, that either have very damp ground or are near a pond or stream. They mate in streams and small ponds.

Diet: It eats insects and other small invertebrates.

Behavior and reproduction: During the day, these frogs hide under stones or in small dips or holes in the ground, but they sometimes will venture out during or after a good rain. They become active from dusk to dawn. Animals that are active only at sunup and sundown are crepuscular (kreh-PUSS-kyoo-ler). Animals active at night are called nocturnal (nahk-TER-nuhl). Using these terms, the parsley frog is both crepuscular and nocturnal. The parsley frogs that live in warmer areas are active almost all year long. Those that live in cooler areas may survive the winter by hibernating. Some hibernate from October to February or March.

When outside from dawn to dusk, the frogs protect themselves from predators in several ways. The colors of the back and head help blend them into the background and make them less noticeable to predators. If a predator does approach them on land, however, they are excellent jumpers and can often leap away. When they are near the water, they will jump in and swim. Although their hind feet do not have much webbing to help boost them through the water, they are still good swimmers. If a predator happens to catch a parsley frog, the warts in its skin ooze a mild poison that may taste bad enough to convince the predator to leave the frog alone.

Their mating season usually begins in the spring, but if the weather is right, they may mate almost any time of year, including the summer and fall. The male's call sounds a bit like a heavy, old door quietly creaking open. Females lay about 50 to 100 eggs at a time and may lay as many as 1,000 to 1,600 eggs a year in small strings or clumps. The eggs are tiny and brown and coated with a thick, see-through gel. The eggs stick to underwater plants and stems and hatch into tadpoles that may grow to be larger than the adult frogs.

Parsley frogs and people: Like most other frogs, this species eats insects that people may consider pests.

Conservation status: This species is not generally considered to be at risk, but Belgium, France, and other countries have listed it as Endangered or Vulnerable. In these areas, the numbers of parsley frogs have declined because of habitat destruction, especially the draining of water. ∎

FOR MORE INFORMATION

Books:

Arnold, E. Nicholas. Reptiles and Amphibians of Europe (Princeton Field Guides). Princeton, NJ: Princeton University Press, 2003.

Arnold, E. N., J. A. Burton, and D. W. Ovenden. Reptiles and Amphibians of Britain & Europe (Collins Field Guide). London: HarperCollins, 1999.

Duellman, William E., and Linda Trueb. Biology of Amphibians. Baltimore: Johns Hopkins University Press, 1994.

Halliday, Tim, and Kraig Adler, eds. The Encyclopedia of Reptiles and Amphibians. New York: Facts on File, 1991.

Zug, George R., Laurie J. Vitt, and Janalee P. Caldwell. Herpetology. 2nd edition. San Diego: Academic Press, 2001.

Web sites:

"Dramatic Declines for European Amphibians." IUCN press release. http://www.countdown2010.net/documents/european%20frog%20and%20toad-2.pdf (accessed on February 14, 2005).

Heying, H. "Pelodytidae" Animal Diversity Web.http://animaldiversity.ummz.umich.edu/site/accounts/information/Pelodytidae.html (accessed on February 14, 2005).

"Iberian Parsley Frog." Amphibians and Reptiles of Europe.http://www.herp.it/indexjs.htm?SpeciesPages/PelodIberi.htm (accessed on February 14, 2005).

"Parsley Frog, Common Parsley Frog, Mud-diver." Amphibians and Reptiles of Europe.http://www.herp.it/indexjs.htm?SpeciesPages/PelodPunct.htm (accessed on February 14, 2005).