Background information and definitions
Captive breeding involves taking wild animals into captivity and establishing and maintaining breeding populations. It tends to be undertaken when wild populations become very small or fragmented or when they are declining rapidly. Captive populations can be maintained while threats in the wild are reduced or removed and can provide an insurance policy against catastrophe in the wild. Captive breeding also potentially provides a method of increasing reproductive output beyond what would be possible in the wild. The aim is usually to release captive-bred animals back to natural habitats, either to original sites once conditions are suitable, to reintroduce species to sites that were occupied in the past or to introduce species to new sites. Some captive populations may also be used for research to benefit wild populations.
Amphibians possess a number of traits that make them potentially suitable for captive breeding programmes. They reach breeding age relatively quickly and are fertile and so captive populations can, in theory, be expanded quickly. Also their small body size and low maintenance requirements allow viable populations to be managed much more cost-effectively than many larger animals. However, captive breeding can result in problems associated with inbreeding depression, removal of natural selection and adaptation to captive conditions.
Studies in which amphibians were treated with hormones to induce sperm or egg release, or eggs were fertilized artificially are discussed in separate sections below.
Studies that investigate the effectiveness of releasing of captive-bred amphibians are discussed in ‘Release captive-bred individuals’. Those studies are not included in this section, unless specific details about captive breeding were included.
Supporting evidence from individual studies
A review of captive breeding programmes (Maruska 1986) found that a number of amphibian species have been bred successfully in captivity. Frog species that bred successfully were: red-eyed tree frog Agalychnis callidryas, Asiatic treefrog Rhacophorus leucomystax, Malaysian leaf frog Megophrys nasuta, Bell’s horned frog Ceratophrys ornate and a number of poison dart frog species (Dendrobatidae). Breeding was induced with gonadotrophin-releasing hormone in White’s tree frog Litoria caerulea (with reduced temperatures) and African red frog Phrynomerus bifasciatus (with simulated wet and dry season).Study and other actions tested
A small, replicated study in 1993 of parsley frogs Pelodytes punctatus at Genoa University, Italy (Emanueli et al. 1997) found that one clutch was produced and hatched in captivity (500 eggs). One of six females bred following a drop in temperature from 20–24 to 17°C. All wild caught tadpoles survived. At metamorphosis the mortality rate of those animals was 19% due to dehydration, calcium deficiency and suffocation during feeding. Thirty-one tadpoles were obtained from the wild in 1993. Tadpoles were housed in a 400 L tank (20 cm water) and metamorphs in a 50 x 50 x 25 cm tank. From eight months animals were housed in a 120 x 60 x 50 cm glass breeding tank with filtered water, pebbles and moss. Eggs were moved to a separate tank.Study and other actions tested
A replicated study in 1993–1997 of captive agile frogs Rana dalmatina in Jersey, UK (Gibson & Freeman 1997) found that frogs bred successfully in one of two captive populations. Breeding occurred at the Jersey Wildlife Preservation Trust in 1994, 1995 and 1997. However, breeding did not occur in the first two years within the five enclosures at the second site. In 1993, three males, two females and 17 juveniles and in 1994 an additional eight juveniles were acquired and housed in a landscaped enclosure with a pond (20 m2). In 1995, an additional five enclosures (3 x 3–7 m) were built on private land and stocked with captive-bred tadpoles and young frogs.Study and other actions tested
A replicated study in 1994–1998 of captive green and black poison-dart frogs Dendrobates auratus and blue poison-dart frogs Dendrobates azureus in Jersey, UK (Preece 1998) found that both species bred successfully in captivity. Fertile black poison-dart frogs’ eggs were first recorded in December 1994 and produced five frogs. In 1995–1996, ninety-eight mainly fertile clutches were produced. The 10 original frogs were still alive and breeding in 1998. Viable blue poison-dart frogs’ eggs were first recorded in August 1996. In 1996–1998, 23 frogs were captive-bred and went on to produce eggs in 1998. Ten captive sub-adult and tadpole black poison-dart frogs and seven blue poison-dart frogs were acquired in 1994 and 1995–1996 respectively. Frogs were housed at 22–27°C in 3 x 2 x 1 m tanks with a waterfall, natural substrate and densely planted areas. Tanks had seasonal photoperiods and were misted daily. Blue poison-dart frogs were moved to smaller tanks in pairs to breed. Frogs were fed young crickets, fruit flies and wild invertebrates. Eggs were removed for rearing.Study and other actions tested
A replicated study in 1994–1996 of roseate frogs Geocrinia rosea at Melbourne Zoo, Australia (Birkett, Vincent & Banks 1999) found that the frogs did not breed successfully in the first two years. Although males called from 1994, eggs were not produced until 1996. However, only one of four egg masses was fertile (25 eggs) and that was destroyed by fungus. Three of the original frogs died within three months, the other two survived 27 months in captivity. The original egg mass produced 45 froglets, 15 of which were alive at 21 months, but died within 27 months of emergence. In 1994, two male and three sub-adult frogs were housed in two outdoor tanks (120 x 60 x 60 cm) with organic substrates and water. Two egg clumps were also received and 6–7 froglets were housed in each of four indoor tanks (47 x 55 x 36 cm and 180 x 46 x 46 cm).Study and other actions tested
A replicated study in 1992–1998 in Hong Kong and Australia (Dudgeon & Lau 1999) found that Romer’s frogs Philautus romeri reproduced in captivity. Over 180 egg clutches were produced in captivity in Hong Kong and at least 706 captive-bred frogs were produced from the captive population in Australia. A total of 1,170 frogs and 1,622 tadpoles were released in 1993–1994. In 1992, several eggs and tadpoles and 230 adults were collected from the wild. Thirty adults were sent to Melbourne Zoo and the remainder were housed at the University of Hong Kong.Study and other actions tested
A replicated study in 1993 of captive sharp snouted dayfrogs Taudactylus acutirostris at Melbourne and Taronga Zoos, Australia (Banks & McCracken 2002) found that only one of 109 animals taken in to captivity survived to 18 months. The one adult died within a month of the introduction of three adults from another zoo, which died at the same time. Of the others, 79 died as tadpoles, 11 during metamorphosis and 18 as metamorphs. Causes of death were largely unknown. In 1993, a total of 109 tadpoles were sent to the two zoos in five separate groups. Tadpoles at Taronga Zoo were housed at 20–23°C in three different-sized tanks with water at different depths (15–45 cm), gravel, stones, wood and pond weed. At Melbourne Zoo, tadpoles were housed at 17–24°C in groups of 8–10 in tanks (45 x 53 x 14 cm). Water was cleaned weekly. Animals were treated for dermatitis.Study and other actions tested
A replicated study in 2000–2001 of captive tarahumara frogs Rana tarahumarae in southern Arizona, USA (Rorabaugh & Humphrey 2002) found that some frogs bred successfully at one of the captive breeding facilities. Wild collected eggs hatched successfully and many of the metamorphosed frogs survived to adulthood. In May 2000, part of an egg mass was collected from the wild in northern Mexico. Eggs were taken to a captive facility in Arizona and after hatching divided between at least six facilities.Study and other actions tested
A replicated study in 1993–2000 of captive great barred frogs Mixophyes fasciolatus at Mebourne Zoo, Australia (Banks et al. 2003) found that frogs bred successfully in captivity. In 1998, males called and three clumps of 300–500 eggs were produced. Nine egg clumps were produced in 1999–2000, some by frogs hatched in 1998. In 1998–2000, over 200 young frogs were sent to other breeders. Breeding also occurred outdoors. Tadpole growth was similar at 16–20°C and 18–22°C, but lower temperatures resulted in later metamorphosis (120–132 vs 99–108 days). A number of frogs had a metabolic bone disease that was successfully treated. In 1993–1995, 12 metamorphs were received and raised to adults. Two breeding groups of four were housed in glass aquaria (180 x 45 x 45 cm) with organic substrate, rocks, logs and water. Rain was simulated for two hours/day and night for six days in April. Tadpoles were housed in separate tanks (45 x 53 x 15 cm). In 2000, seven frogs were housed in an outdoor enclosure (300 x 300 x 220 cm).Study and other actions tested
A replicated study in 2000–2003 in Gipuzkoa province, Spain (Rubio & Etxezarreta 2003) found that stripeless treefrogs Hyla meridionalis reproduced successfully in captivity. In 2000–2003, a total of 5,767 tadpoles were bred in captivity and released (171–3,989/year).Study and other actions tested
A replicated study in 2000–2004 of captive tarahumara frogs Rana tarahumarae in Arizona, USA (Rorabaugh 2005) found that frogs bred successfully at both high and low maintenance captive facilities. Animals were collected from northern Mexico in 2000. They were reared and bred at a number of facilities ranging from high maintenance to semi-wild low maintenance. In June–October 2004, 56 adult, 229 juvenile and 328 tadpoles were released at four sites in south central Arizona.Study and other actions tested
A replicated study in 1997–2000 in Italy (Mattioli, Gili & Andreone 2006) found that successful captive breeding was achieved for the golden mantella Mantella aurantiaca, false tomato frog Dyscophus guineti and green burrowing frog Scaphiophryne marmorata. A stable breeding population of 60 golden mantellas was achieved (2 clutches/female/year; 60% eggs hatch; 80% survival to adult). Six founder false tomato frogs resulted in a breeding population of 100 frogs (1; 30%; 50%). Green burrowing frogs also bred successfully (1; 80%; 90%). The estimated cost of one captive-bred individual was: 7.50 € for golden mantillas, 3.12 € for tomato frogs and 0.54 € for green burrowing frogs. Animals were imported from Madagascar in 1997–1998 or were obtained from private breeders or other facilities. Reproduction was monitored in captivity over two years. Some data were obtained from private breeders. Costs were calculated for Italy.Study and other actions tested
A small, replicated study in 2006 of the Fijian ground frog Platymantis vitianus at the University of the South Pacific, Fiji (Narayan, Christi & Morley 2007) found that although all five froglets that hatched survived to 37 days old, they were then predated by brown house ants Pheidole megacephala. All froglets maintained their body weight and on average, weight and body length gradually increased. Ants were likely to have been attracted by excess ripe fruit placed in the aquarium to attract small flies as food for the froglets. Adult frogs laid eggs during the wet season in a purpose-built outdoor enclosure. The five newly hatched froglets were then transferred into a glass laboratory aquarium (0.5 x 0.3 x 0.4 m). Body weight and food supply were closely monitored.Study and other actions tested
A small, replicated study in 2006–2007 of Fijian ground frogs Platymantis vitianus at the University of the South Pacific, Fiji (Narayan et al. 2007, Narayan et al. 2009) found that following incubation, 35 froglets hatched from one egg mass (88%; see also Narayan, Christi & Morley 2007). Two egg masses (40–42 eggs/mass) were laid by captive frogs in the wet season (December/January) of the first year. Only 11% of eggs from one mass hatched due to flooding and so the second was incubated inside a glass aquarium at 27°C. Thirty-five froglets hatched from the second batch. Five adult male and five female frogs collected from the wild were kept in outdoor wire enclosures (5 x 3 x 2 m). Newly hatched froglets were transferred to laboratory glass aquariums (0.5 x 0.3 x 0.4 m).Study and other actions tested
In a continuation of a study at the University of the South Pacific, Fiji (Narayan et al. 2007, Narayan 2009), a small, replicated study (Narayan et al. 2007) found that adding natural structures to enclosures as potential egg laying sites resulted in the production of two clutches of eggs by Fijian ground frogs Platymantis vitianus. One clutch was laid underneath a moist rotting log in December and the other inside a bamboo stem lined with soil in January. Several of the five males and five females were observed in or near potential egg-laying sites throughout the breeding period. Natural structures were added as potential egg laying sites including rotting logs, hollow bamboo stems, coconut husks, rocks and decaying leaf litter. All material was sterilized prior to installation. Native plants were also added. Nocturnal activity was recorded using digital video surveillance cameras.Study and other actions tested
A replicated study in 1992–1996 of Romer’s tree frog Chirixalus romeri at Melbourne Zoo, Australia and the University of Hong Kong (Banks, Lau & Dudgeon 2008) found that they bred successfully in captivity. Over 188 clutches of eggs were produced in Hong Kong in 1992–1996, 108 from wild and 76 from captive-bred females. Average juvenile mortality rate was 49% (range 31–71%). Five of 13 frogs survived until they were released to the wild five years after metamorphosis. Frogs in two terrariums died of red-leg syndrome. In Australia, seven egg clutches and 250 froglets were produced in 1991, with a froglet mortality rate of 83% at eight months. In 1992, 18 egg clutches (seven from wild and 11 from captive-bred females) and 530 froglets were produced. A total of 220 adults (150 males), 21 juveniles, metamorphs and tadpoles and seven egg clutches were collected from the wild in 1991–1992. Ten to 25 adults were housed per tank (60 x 30 x 30 cm). Tadpoles were raised in small tanks (up to six/100 cm2) and froglets transferred to tanks.Study and other actions tested
A review of captive breeding programmes in 2001–2007 of priority amphibian species from Panama at 50 zoos and aquariums in the USA (Gagliardo et al. 2008) found that maintenance and breeding in captivity had mixed success. Several of 30 species collected bred successfully in captivity including lemur leaf frog Hylomantis lemur, Pratt's rocket frog Colostethus pratti, marsupial frog Gastrotheca cornuta, spiny-headed treefrog Anotheca spinosa, Vicente's poison frog Dendrobates vicentei, minute poison frog Minyobates minutus, Eleutherodactylus gaigae and caretta robber frog Pristimantis diastema. However, some have proved difficult to raise to adulthood due to nutritional issues (e.g. marsupial frog). Species such as Palmer's treefrog Hyloscirtus palmeri and banded horned treefrog Hemiphractus fasciatus proved very difficult to maintain in captivity. Death was often related to malnutrition. Up to 40 individuals of nearly 30 species were wild caught.Study and other actions tested
A replicated study in 2007–2008 of captive amphibians at a facility in Hanoi, Vietnam (Truong et al. 2009) found that Hylarana maosonensis, Rhacophorus feae, Rhacophorus maximus and Chinese gliding frogs Rhacophorus dennysi bred successfully in captivity. Following successful breeding in 2007, 300 Chinese gliding frog froglets were released into the wild in June 2008 at the location that the parents had been collected. Rhacophorus feae and Rhacophorus maximus were also to be released into the wild.Study and other actions tested
A replicated study in 2005–2008 of captive horned marsupial frog Gastrotheca cornuta in Atlanta and Panama, USA (Gagliardo et al. 2010) found that a small number of frogs bred in captivity but froglet survival was low. In Panama, one female produced 14 froglets in 2007 and four eggs were produced in 2008. In Atlanta, 14 infertile eggs were produced in 2006, however 13 froglets were observed in 2008. Two cases of abortion were recorded and most froglet deaths occurred within 20 weeks. In total, 11 frogs survived over one year, but grew slowly and often had deformities. One receiving UV-B radiation for 45 minutes/day did not develop deformities. Wild frogs were collected in 2005–2006. Males and females were housed in separate enclosures (60 x 30–60 x 40–90 cm) with plants, twigs and water in Atlanta (six males, two females) and Panama. Males were introduced to females just for breeding. Frogs were misted 2–10 times/day and in Atlanta a ‘dry season’ was simulated. Froglets were separated for rearing.Study and other actions tested
A replicated study in 2009–2010 of captive mantella frogs in Edmonton, Canada (Woods 2010) found that three of four species bred successfully. In October 2009, baron’s painted mantella Mantella baroni and splendid mantella Mantella pulchra produced clutches of eggs. Eggs left in with parents developed better than those moved to dishes. Survival rate was approximately 60%. In October of 2010, golden mantella Mantella aurantiaca produced two large clutches, with 211 tadpoles hatching. Survival rate to froglets by the end of the study was 75%. Climbing mantella Mantella laevigata did not breed. In June 2009, all species except golden mantella were put through a three month dry cycle, with reduced temperature (<20°C), humidity and food (alternate days) and increased day length (12 hours). In September, the wet season was started (misting four times/day, 10 hours daylight, daily feeding). Eggs were kept in petri dishes on wet moss or left in with the parents. Tadpoles were placed into plastic containers. In 2010, one male and three female golden mantellas were put through just a wet season.Study and other actions tested
A replicated study in 2008–2012 of captive white-bellied frogs Geocrinia alba at Perth Zoo, Australia (Bradfield 2011) found that the species bred successfully for the first time in captivity in 2012. Three egg clutches were laid in the breeding chambers. The eggs in one nest failed to develop but fertile eggs from the other two metamorphosed and were still alive at two months.Study and other actions tested
A review of a captive breeding programme from 2001 to 2011 for lemur leaf frogs Agalychnis lemur in the UK (Gray 2011) found that the frogs bred successfully in captivity. Captive-bred animals were sent to breeding facilities around the world. Forty animals were sent to Europe from Bristol Zoo in 2011.Study and other actions tested
A replicated study in 2010–2012 of a captive breeding programme for Eleutherodactylus species of frogs at the Philadelphia Zoo, USA (Martínez Rivera, Bell & Parker 2011) found that six of 10 species produced offspring, but only three species were raised successfully. In 2011, eight of the 10 species laid eggs. Six of those species laid fertilized eggs that produced offspring. The three species that were raised successfully were Mozart’s frog Eleutherodactylus amadeus, la hotte frog Eleutherodactylus bakeri and Macaya breast-spot frog Eleutherodactylus thorectes. By 2011, the zoo held over 650 frogs of the 10 species. In 2010, 176 frogs of 10 critically endangered species were collected from four sites in Haiti. Frogs were housed in seven biosecure enclosures with water filtration, lighting, temperature control, misting systems and heat lamps. Tanks had soil substrate and plants. Each species was kept separate, within breeding groups (3–15 frogs).Study and other actions tested
A replicated study in 2009–2011 at San Diego Zoo, California, USA (Medlin 2011) found that mountain yellow-legged frogs Rana muscosa reproduced in captivity. Breeding success improved from 2009 to 2011 as frogs matured and with winter cooling to replicate natural conditions. In 2006, 82 tadpoles were rescued from a drying stream. Breeding was attempted from 2009. In 2010, half of the frogs and in 2011 all frogs were kept at 4°C for 2–3 months over winter. In 2010–2011, 330 eggs and 336 tadpoles were released into a stream. Tadpoles were kept in cages to acclimatize for different periods of time before release.Study and other actions tested
A small, replicated study in 2010–2011 of Orlov’s treefrog Rhacophorus orlovi in Leningrad Zoo, Russia (Wildenhues et al. 2011) found that two pairs bred successfully in captivity. Reproduction first took place during the first two months of captivity. Fertilization rate of the first three egg masses were 0%, 90% and 30%; a further eight egg masses were produced within seven months. The following year, 50% of egg masses were infertile, but juveniles survived to at least 12 months. Two pairs of frogs were caught in the wild in Ha Tinh Province, Vietnam in 2010. They were housed at 19–24°C in glass tank (20 x 40 x 30 cm) with branches and plants. Tadpoles were kept in plastic tanks (39 x 28 x 22 cm). Froglets were kept in groups of 15–17 in glass tanks similar to adults.Study and other actions tested
Referenced paperWildenhues M.J., Bagaturov M.F., Schmitz A., Dao T.T.A., Hendrix R. & Ziegler T. (2011) Captive management and reproductive biology of Orlov’s treefrog, Rhacophorus orlovi Ziegler & Köhler, 2001 (Amphibia: Anura: Rhacophoridae), including larval description, colour pattern variation and advertisement call. Der Zoologische Garten: Zeitschrift für die Gesamte Tiergärtnerei (Neue Folge), 80, 287–303.
A replicated study in 2011–2012 of captive frogs in Andasibe, Madagascar (Edmonds & Claude 2012) found that two of eight local species bred in the first year of captivity. Both Boophis pyrrhus and Mantidactylus betsileanus bred in captivity in 2012. Tadpoles and frogs were raised in captivity to determine the optimal husbandry requirements for these species so that they could be applied to maintaining threatened similar species in the future. In April 2011, eight local frog species were housed in a newly constructed biosecure captive breeding facility.Study and other actions tested
A replicated study in 2010–2011 of Darwin’s frogs Rhinoderma species at the National Zoo of Chile, Santiago, Chile (Fenolio 2012) found that the frogs bred successfully in captivity. Reproductive activity and the first young were produced a few months after arriving in captivity. More juveniles were produced the following year. Breeding groups of Darwin’s Frogs were collected from wild populations in 2010. Frogs were housed in enclosures with automatic misting systems, climate control and pre-filtered water.Study and other actions tested
A replicated study in 2006–2012 of amphibians at two breeding facilities in Panama (Gratwicke 2012) found that two undescribed species at risk of extinction and la loma treefrog Hyloscirtus colymba were not successfully raised to adulthood.Study and other actions tested
A replicated study in 2005–2011 of captive cascade glass frogs Sachatamia albomaculata at Zoo Atlanta and Minnesota Zoo, USA (Hill et al. 2012) found that animals bred successfully in captivity. Few eggs were produced in 2005–2007. However, regular breeding occurred from 2008. Eggs were produced in most months (28–60/clutch). The first metamorphosis was recorded in March 2009 and continued throughout 2009 to 2011. Fifteen wild caught frogs were caught in 2005 and divided between two zoos. They were housed in groups of two to four in tanks (30 x 30 x 45 cm) with aquatic plants. Tanks were misted six times each day in November–April and twice a day in May–October. Eggs, larvae (30/tank), metamorphs (1/container) and froglets were kept in separate containers.Study and other actions tested
A small, replicated study in 2011–2012 of captive Scinax alcatrazin at São Paulo Zoo, Brazil (Lisboa 2012) found that eggs were produced and juveniles maintained in captivity. The first breeding event occurred after 33 days in captivity. One female deposited around 140 eggs, of which 132 hatched. By July 2012, 93 froglets were still alive. Two males and a female died on the first day in captivity. Eleven animals (five males, three females, three tadpoles) were collected from the wild in October 2011 and housed in a biosecure room. Adults were kept in two glass enclosures, with plants and water. An ultra-sonic fogger was used to increase night-time humidity to stimulate breeding. Tadpoles were housed in a plastic enclosure and froglets in plastic cups. Management and husbandry protocols had been established over two years using captive Scinax perpusillus (see Lisboa & Vaz 2012).Study and other actions tested
A small, replicated study in 2009–2010 of Scinax perpusillus at São Paulo Zoo, Brazil (Lisboa & Vaz 2012) found that eggs were produced in captivity. Five batches of 4–77 eggs were laid in 2010 by one female. Two of three adult males died during the year. The three males, one female and six larvae were wild caught in 2009. Following five months quarantine, adults were housed at 12–27°C in a glass tank (70 x 30 x 45 cm) with a water dish and plants. Tanks were misted once or twice a day and before breeding an ultra-sonic fogger was turned on for 10 hours overnight three times a week. Management and husbandry protocols were established using this species in preparation for attempted captive breeding of Scinax alcatrazin (see Lisboa 2012).Study and other actions tested
A small, replicated study in 2005–2009 of captive Malayan horned frogs Megophrys nasuta at Cologne Zoo, Germany (Wildenhues et al. 2012) found that frogs bred successfully. Between 50 and 300 larvae hatched/egg batch. The minimum interval between egg laying was about a month. Dry followed by phases of intense water spraying triggered reproduction. Larval development was faster at higher water temperatures and lower densities. Three males and two females obtained from the pet trade were housed in aquariums (145 x 60 x 56 cm) divided into aquatic and terrestrial sections. Larvae were moved to plastic tanks (13 L water). Two–month-old tadpoles were transferred into aquariums (54 x 65 x 30 cm) and metamorphs and juveniles, in groups of 20–30, into tanks (60 x 45 x 30 cm).Study and other actions tested
Referenced paperWildenhues M., Rauhaus A., Bach R., Karbe D., van der Straeten K., Hertwig S.T. & Ziegler T. (2012) Husbandry, captive breeding, larval development and stages of the Malayan horned frog Megophrys nasuta (Schlegel, 1858) (Amphibia: Anura: Megophryidae). Amphibian & Reptile Conservation, 5, 15-28.
A replicated study in 1994–2004 at Taronga Zoo, Australia (McFadden 2012a) found that captive breeding of green and golden bell frogs Litoria aurea was very successful. The captive breeding programme was established in 1994. Between 1996 and 2004, over 20,000 tadpoles and metamorphs, including fourth generation captive-bred individuals, were released at five sites.Study and other actions tested
A replicated study in 2011–2012 of captive southern corroboree frogs Pseudophryne corroboree at Taronga and Melbourne Zoo, Australia (McFadden 2012b) found that frogs reproduced successfully in captivity. Having had difficulties breeding the species in the first years of the programme, captive breeding protocols had been established that resulted in high reproductive success. In 2011 and 2012, the majority of mature females produced eggs. Eggs were separated and observed during early development. Captive breeding was undertaken as less than fifty individuals remained in the wild, mainly because of chytridiomycosis.Study and other actions tested