OLMS AND MUDPUPPIES: Proteidae

PHYSICAL CHARACTERISTICS

Olms and mudpuppies are medium-sized to large salamanders with a long, squared-off snout, small legs, and large, bushy, red gills. Gills are organs for obtaining oxygen from water. Most olms are pale and nearly eyeless. Mudpuppies are dark with large spots and have small eyes. Olms and mudpuppies are large for salamanders, more than 16 inches (40 centimeters) from the tip of the snout to the tip of the tail.

Olms and mudpuppies spend their entire lives in water, never making the move to land the way many amphibians do. Amphibians (am-FIB-ee-uhns) are vertebrates (VER-teh-brehts), or animals with a backbone, that have moist, smooth skin; are cold-blooded, meaning their body temperature is the same as the temperature of their surroundings; and, in most instances, have a two-stage life cycle. Olms and mudpuppies have the same body features as adults that they do as larvae. Larvae (LAR-vee) are animals in an early stage that change body form in a process called metamorphosis (MEH-tuh-MORE-feh-sis) before becoming adults. These features include three pairs of large, bushy, red gills; a short tail that is flat from side to side, like an eel's tail; a tail fin; and small eyes.

GEOGRAPHIC RANGE

Olms live in southeastern Europe, and mudpuppies live in eastern North America. The Appalachian Mountains form a wedge separating the coastal waterdogs from the inland mudpuppies. Olms live in the limestone cave systems along the Adriatic Sea from western Slovenia and northeastern Italy in the north to Montenegro in the south. Most of them live in western Slovenia.

HABITAT

Olms and mudpuppies live in freshwater. Olms live in underground streams and lakes in limestone caves, where it is always dark and where the water is cold year-round, usually about 46°F (8°C). These salamanders are thought to group together in deep cracks in the stone. Most sightings and captures of olms have been in places where they either have been flushed out by heavy rains or have been hunting for food. Mudpuppies live in muddy canals; ditches; large, rocky, fast-flowing streams; reservoirs; and large, cool lakes. Mudpuppies can be found at all seasons of the year and are even active beneath the ice in mid-winter.

DIET

Mudpuppies eat fish, fish eggs, crayfish, worms, small mollusks, and water insects, in short, almost anything that moves and will fit into their mouths. They are especially fond of fish called sculpins and sometimes can be found gorged with these fish. Little is known about what olms eat in the wild, except that they seem to feed on tiny crustaceans, insect larvae, and other small invertebrates. Olms use chemical sensors to find prey in total darkness. Mollusks (MAH-lusks) are animals with a soft, unsegmented body that may or may not have a shell, such as slugs and snails. Crustaceans (krus-TAY-shuns), such as crayfish, are water-dwelling animals that have jointed legs and a hard shell but no backbone.

The Mudpuppy Goes to College

Mudpuppies are the most commonly used amphibians in college comparative anatomy and physiology classes.

BEHAVIOR AND REPRODUCTION

Mudpuppies crawl slowly over the bottoms of streams and lakes, but they can swim rapidly when frightened. In captivity, mudpuppies are secretive and hide under any available object, including one another. They appear to be repelled by light. In water with a low amount of oxygen, mudpuppies constantly fan their gills, which can become large, bushy, and bright red. Under such conditions, the mudpuppies often rise to the surface to take gulps of air. In water with plenty of oxygen the gills tend to be held motionless against the sides of the neck and eventually shrink. There is some evidence that mudpuppies are capable of homing behavior. Olms are friendly to one another, at least when they are not breeding, and tend to group together in deep cracks in the cave walls. Scientists believe olms use chemical sensors to mark and find their home shelters.

Scientists know little about how olms and mudpuppies reproduce. The breeding season for mudpuppies is in the fall or winter, depending on the species and where the animals live. Males that are ready to mate have a swollen cloaca and a pair of enlarged finger-like structures that stick out toward the rear of the body. The cloaca (kloh-AY-kuh) is the chamber in some animals that holds waste from the kidneys and intestines, holds eggs or sperm about to be released to the outside, holds sperm entering a female's body, and is the passage through which young are born.

Breeding in olms does not appear to be related to the seasons, reflecting the stability of their underground habitat. Olms seem to be much more territorial than mudpuppies during breeding. All species for which information is known use some kind of mating ritual in which the males and females stimulate each others' cloacas. The male then releases a bag of sperm, which the female picks up with her cloaca. The female may store sperm in special structures inside her cloaca for six months or more. Fertilization (FUR-teh-lih-ZAY-shun), or the joining of egg and sperm to start development, takes place inside the female's body. When the female lays them, the eggs usually attach to the bottom of an object such as a rock or a log, and the female guards them.

The eggs of olms and mudpuppies hatch two to six months after they are laid, depending on the species and the temperature. The larvae develop gradually into adults without going through metamorphosis. Scientists do not know when mudpuppies are old enough to reproduce, but olms can reproduce when they are seven years old. Scientists believe olms and mudpuppies live nine to sixty years.

OLMS, MUDPUPPIES, AND PEOPLE

Olms and mudpuppies have long been used for scientific studies. Mudpuppies are caught and sold as pets. Olms are a tourist attraction, particularly in Slovenia. Because of their thin skin and dependence on clean water with plenty of oxygen, olms and mudpuppies may be good indicators of water quality.

CONSERVATION STATUS

The World Conservation Union (IUCN) lists one species of olms and mudpuppies as Endangered, one as Vulnerable, and one as Low Risk/Near Threatened. Endangered means facing very high risk of extinction in the wild. Vulnerable means facing high risk of extinction in the wild. Low Risk/Near Threatened means at risk of becoming threatened with extinction in the future.

Olms have been protected in Slovenia since 1949. The main threats to olms are economic development, industrial pollution, and over-collecting. Mudpuppies are threatened by chemical pollution, changes in habitat, and over-collecting.

OLM (Proteus anguinus): SPECIES ACCOUNTS

Physical characteristics: Olms are long and thin and have pale, pinkish white skin. The head is flat and narrow, and the eyes are tiny. Three pink gills stick out from each side of the head. The legs are small, and there are only three toes on the front feet and two toes on the rear feet. These features are thought to be adaptations to living in underground waterways. Some olms turn darker when exposed to light. These olms have larger eyes than do olms that never leave their caves. Olms have a squared-off snout and a short tail that is flat from side to side. They reach a length of about 12 inches (30 centimeters) from tip of snout to tip of tail.

Geographic range: Olms live in Europe from the Dinaric Alps of Slovenia and Italy in the north to Montenegro in the south.

Habitat: Olms live in underground lakes and rivers in limestone caves.

Diet: Olms feed at night, using chemical sensors to find small crustaceans and insects and other invertebrates.

Behavior and reproduction: Olms are friendly to one another except during the breeding season, when they defend their territory. Olms are secretive and rarely seen, except when they leave their caves either to feed or because of flooding. Breeding is not related to the seasons. Fertilization takes place inside the female's body after she picks up a sperm bag that has been released by a male. The fertilized (FUR-teh-lyzed) eggs are large and yellowish and are laid under rocks and other cover and guarded by the female. The eggs hatch in about six months. Larvae develop directly into adults without going through metamorphosis. Scientists believe some olms give birth to a pair of well-developed young rather than laying a batch of eggs.

Olms and people: Olms are a tourist attraction. They are popular in the pet trade and are used in scientific research.

Conservation status: The World Conservation Union (IUCN) lists olms as Vulnerable, or facing high risk of extinction in the wild. ∎

MUDPUPPY (Necturus maculosus): SPECIES ACCOUNTS

Physical characteristics: Mudpuppies reach a length of 8 to 19 inches (20 to 48 centimeters) from tip of snout to tip of tail. They have small eyes, a short tail, small legs, and a squared-off snout. Mudpuppies have camouflage coloring against the dark bottom of lakes, rivers, and streams. The colors vary from deep rusty brown to gray or even black with scattered black or bluish black spots and blotches. The spots sometimes form two rows along the back. A dark bar extends through the eye to the gills. The belly is paler than the back and may or may not have dark spots. The edges of the tail often are tinged with reddish orange. The colors of mudpuppy larvae can be strikingly different from that of adults.

Mudpuppies have different shapes of gills, depending on their environment. Mudpuppies that live in the fast-moving waters of rivers and streams have small gills that stay close to the sides of the animal's head. In warm or slow-moving rivers and lakes, the gills are big and bushy.

Geographic range: Mudpuppies live in North America in a range that covers essentially the entire Mississippi River drainage system. The range extends from southern Manitoba and Quebec, Canada, in the north to Georgia, Alabama, Mississippi, and Louisiana, United States, in the south.

Habitat: Mudpuppies live in a variety of water habitats, including rivers, streams, canals, and lakes.

Diet: Mudpuppies eat water-dwelling invertebrates and vertebrates, including crayfish and other crustaceans, mollusks, worms, insect larvae, fish, and other amphibians.

Behavior and reproduction: Mudpuppies are active all year and have been seen moving around beneath the ice in mid-winter. Adults are mostly active at night, when they look for food. Mudpuppies hide under rocks and other objects or in burrows during the day. The mating season for mudpuppies is in the autumn or winter, possibly extending into spring, depending on where they live. The fertilized eggs are laid in May or June and attach to the bottoms of large rocks. The female takes care of the eggs and defends them against predators. Hatching takes place in one or two months, depending on the temperature of the water. The newly hatched larvae are approximately 1 inch (2.5 centimeters) long and have two yellow stripes on a dark background. Mudpuppies grow into adults without going through metamorphosis.

Mudpuppies and people: Mudpuppies are collected in large numbers by biological supply companies for use in classrooms and laboratories around the world. They also are caught and sold as pets.

Conservation status: Mudpuppies are not considered threatened or endangered. ∎

FOR MORE INFORMATION

Books:

Arnold, E. N., and J. A. Burton. Field Guide to the Reptiles and Amphibians of Britain and Europe. 2nd ed. London: HarperCollins Publishers, 1998.

Bernhard, Emery. Salamanders. New York: Holiday House, 1995.

Bishop, S. C. Handbook of Salamanders. Reprint. Ithaca, NY: Cornell University Press, 1994.

Conant, Roger, and Joseph T. Collins. A Field Guide to Reptiles and Amphibians, Eastern and Central North America. New York: Houghton Mifflin, 1991.

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

Lawlor, Elizabeth P. Discover Nature in Water and Wetlands. Mechanicsburg, PA: Stackpole, 2000.

Llamas Ruiz, Andres. Reptiles and Amphibians: Birth and Growth. New York: Sterling, 1996.

Petranka, J. W. Salamanders of the United States and Canada. Washington, DC: Smithsonian Institution Press, 1998.

Web sites:

Hawes, Alex. "On Waterdogs, Mudpuppies, and the Occasional Hellbender." Zoogoer.http://nationalzoo.si.edu/Publications/ZooGoer/2000/2/waterdogsmudpuppieshellbender.cfm (accessed on April 8, 2005).

Heying, H. "Proteidae." Animal Diversity Web.http://animaldiversity.ummz.umich.edu/site/accounts/information/Proteidae.html (accessed on April 8, 2005).

"Mudpuppy and Waterdog." BioKIDS.http://www.biokids.umich.edu/critters/information/Necturus_maculosus.html (accessed on April 8, 2005).

"Proteidae (Gray, 1825) Mudpuppies, Waterdogs, and Olms." Livingunderworld.org.http://www.livingunderworld.org/caudata/database/proteidae (accessed on April 8, 2005).

Siebert, E. "Necturus maculosus." Animal Diversity Web.http://animaldiversity.ummz.umich.edu/site/accounts/information/Necturus_maculosus.html (accessed on April 8, 2005).