Harlequin Frogs True Toads and Relatives: Bufonidae

The World Conservation Union (IUCN) lists five species in this family as Extinct, which means that they are no longer in existence. These include the golden toad, the last of which was seen in 1989; the jambato toad, last seen in 1988; the longnose stubfoot toad, last seen in 1989; and two other species known only by their scientific names: Adenomus kandianus, last seen more than one hundred years ago; and Atelopus vogli, the only individuals of which were seen only during a 1933 expedition and in just one spot in the world. Scientists are especially concerned about the species that disappeared in the late 1980s. Although they are not certain, they believe that the frogs may have died off because of infection with a fungus, known as chytrid (KIT-rid) fungus, which has harmed many different species around the world. Global warming, which has changed the world's weather patterns, pollution, the introduction of fish that eat frogs, and loss of habitat may also have played a role in some of the species' extinctions.

In addition, the IUCN lists the Wyoming toad as Extinct in the wild. This means that the frog is no longer alive except in captivity or through the aid of humans. The Wyoming has a typical toad appearance: chubby body, numerous warts on its back and legs, large paratoid glands, and a short, round-snouted face. It once lived in a larger part of Wyoming and was quite common in the 1950s, but began to disappear in the 1960s. Scientists had thought that it had already become extinct by the 1980s, but a small population turned up in 1987. The toad now only exists within a national wildlife refuge. Currently, ecologists are keeping a watchful eye on the population and are raising toadlets in captivity to release into the refuge. Without this help, scientists believe the toads would likely have already become extinct. They are unsure why the frogs are disappearing, but think that the chytrid fungus may have been a cause.

Other frogs noted by the IUCN include eighty-two species that are Critically Endangered and face an extremely high risk of extinction in the wild; seventy species that are Endangered and face a very high risk of extinction in the wild; forty-nine that are Vulnerable and face a high risk of extinction in the wild; twenty-six that are Near Threatened and at risk of becoming threatened with extinction in the future; and sixty that are Data Deficient, which means that scientists do not have enough information to make a judgment about the threat of extinction.

The U.S. Fish and Wildlife Service lists three U.S. species as being Endangered and one as Threatened. The Endangered species are the Wyoming toad, which was described above, the Houston toad, and the arroyo or southwestern toad. The Threatened species is the Puerto Rican crested toad.

The Houston toad, which the IUCN also considers to be Endangered, once lived in Texas along the coast of the Gulf of Mexico. It became less common in the last half of the twentieth century when the city of Houston became bigger and people began building in what had been the toad's habitat. In addition, the area had a spell of extremely dry weather, which also hurt the toads. The toads now live in a much smaller area.

Half of the arroyo toads, listed by both the U.S. Fish and Wildlife Service and the IUCN as Threatened, disappeared between 1994 and 2004. The toads make their homes in parts of northwestern Mexico and California. The drop in their numbers probably happened as the result of several things, including the construction of roads, dams, and buildings; too much cattle grazing, which is hurting the plants in the frog's habitat, and the introduction of frog-eating fish to the toads' habitat.

Only twenty percent of the Puerto Rican crested toads that lived on Earth in 1994 were left by 2004. As of 2004, fewer than 250 adult toads remained in the wild. The species is listed as Threatened by the U.S. Fish and Wildlife Service and Critically Endangered by the IUCN. The toad, which is native to Puerto Rico and the British Virgin Islands, probably disappeared because people began cutting down and building in the forest where the toads lived so people could move into and live in the area. According to the IUCN, people drained the pools of water where the toads once mated and laid their eggs to make the area into parking lots. Scientists have been able to raise baby crested toads in captivity, but when they are set free, these young toads die. One small population of toads still survives in the wild. It lives inside a national forest and appears to be safe from further habitat destruction.