The Kihansi spray toad (Nectophrynoides asperginis ) is a small toad endemic to Tanzania. The species is live-bearing and insectivorous. The Kihansi spray toad is currently categorized as "Extinct in the wild" by the International Union for Conservation of Nature (IUCN), though the species persists in ex situ, captive breeding populations.
An insectivore is a carnivorous plant or animal that eats insects. An alternative term is entomophage, which also refers to the human practice of e...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
Jumping (saltation) can be distinguished from running, galloping, and other gaits where the entire body is temporarily airborne by the relatively l...
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starts withThe Kihansi spray toad is a small, sexually dimorphic anuran, with females reaching up to 2.9 cm (1.1 in) long and males up to 1.9 cm (0.75 in). The toads display yellow skin coloration with brownish dorsolateral striping. They have webbed toes on their hind legs, but lack expanded toe tips. They lack external ears, but do possess normal anuran inner ear features, with the exception of tympanic membranes and air-filled middle ear cavities. Females are often duller in coloration, and males normally have more significant markings Additionally, males exhibit dark inguinal patches on their sides where their hind legs meet their abdomens. Abdominal skin is translucent, and developing offspring can often be seen in the bellies of gravid females. The toad breeds by using internal fertilization, in which females retain larvae internally in the oviduct until their offspring are born.
Prior to its extirpation, the Kihansi spray toad was endemic only to a two-hectare (5-acre) area at the base of the Kihansi River waterfall in the Udzungwa escarpment of the Eastern Arc Mountains in Tanzania. The Kihansi Gorge is about 4 km (2.5 mi) long with a north–south orientation. A number of wetlands made up the habitat of this species, all fed by spray from the Kihansi River waterfall. These wetlands were characterized by dense, grassy vegetation including Panicum grasses, Selaginella kraussiana moss, and snail ferns (Tectaria gemmifera ). Areas within the spray zones of the waterfall experienced near-constant temperatures and 100% humidity. Currently, an artificial gravity-fed sprinkler system is in place to mimic the original conditions of the spray zones. The species' global range covered an area of less than two hectares around the Kihansi Falls, and no additional populations have been located after searching for it around other waterfalls on the escarpment of the Udzungwa Mountains.
An ex situ breeding program is maintained by North American zoos in the effort to reintroduce the species back into the wild. The program was initiated in 2001 by the Bronx Zoo when almost 500 Kihansi spray toads were taken from their native gorge and placed in six U.S. zoos as a possible hedge against extinction. Initially its unusual life style and reproduction mode caused problems in captivity, and only Bronx Zoo and Toledo Zoo were able to maintain populations. By December 2004, fewer than 70 remained in captivity, but when their exact requirements were discovered greater survival and breeding success was achieved. In November 2005, the Toledo Zoo opened an exhibit for the Kihansi spray toad, and for some time this was the only place in the world where it was on display to the public. The Toledo Zoo now has several thousand Kihansi spray toads, the majority off-exhibit. The Bronx Zoo also has several thousand Kihansi spray toads, and it opened a small exhibit for some of these in February 2010. In 2010 Toledo Zoo transferred 350 toads to Chattanooga Zoo, which has created a small exhibit for them. Groups numbering in the hundreds are now also maintained at Detroit Zoo and Omaha's Henry Doorly Zoo.
In August 2010, a group of 100 Kihansi spray toads were flown from the Bronx Zoo and Toledo Zoo to their native Tanzania, as part of an effort to reintroduce the species into the wild, using a propagation center at the University of Dar es Salaam. In 2012, scientists from the center returned a test population of 48 toads to the Kihansi gorge, having found means to co-inhabit the toads with substrates presumed to contain chytrid fungus. The substrates were extracted from the Kihansi gorge spray wetlands, and mixed with captive toads with their surrogate species from the wild. Reintroduction commenced because its substrate appeared to not harbor any infectious agents that could threaten the survival of the species. In 2017 a reintroduction program will be launched and currently a few Kihansi spray toads will be successfully reintroduced in Tanzania.
Despite strict protocols in the breeding facilities, toads are occasionally attacked by chytrid fungus, resulting in mass deaths at the Kinhansi facility. Air conditioning and water filtration system malfunctions have also contributed to toad mortality. Researchers suggest that reintroduction of the species in the wild might take time because it needs to adapt slowly to the wild habitat in which it needs to search for food, evade predators, and overcome disease, in contrast to the controlled environment they lived in during captivity.
