Breed reptiles in captivity: Tuatara

Overall effectiveness category Awaiting assessment
Number of studies: 1
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Effectiveness

not assessed
Certainty

not assessed
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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. However, captive breeding can result in problems associated with inbreeding depression, removal of natural selection and adaptation to captive conditions. 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.

Due to the number of studies found, this action has been split by species group, though no studies were found for amphisbaenians. See here for other species groups.

For studies that investigate the effectiveness of releasing captive-bred reptiles see Release captive-bred reptiles into the wild.

Study locations

Key messages

One study evaluated the effects of breeding tuatara in captivity. This study was in New Zealand.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

Reproductive success (1 study): One replicated study in New Zealand reported that hatching success of eggs laid in captivity by tuatara was around 50%. The study also found that the first clutches were laid 2–8 years after tuatara were brought into captivity.

BEHAVIOUR (0 STUDIES)

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated study in 1990–2007 in artificial enclosures in North Island, New Zealand (Keall et al. 2010) reported that wild tuatara Sphenodon punctatus bred multiple times in captivity but that fewer than half of eggs hatched successfully. Over 16 years, 241 of 553 eggs (44%) laid by tuatara in captivity hatched successfully. Clutches were laid in 13 of 16 years by 15 of 22 females. The first clutches were laid 2–8 years after tuatara were brought into captivity. Hatching success and adult survival varied between tuatara taken from different islands (see original paper for details). Three captive-born females also produced three clutches during the study. In 1990–1992, four populations of tuatara were brought into captivity from four islands (6–15 individuals/island) to one of three captive facilities pending eradication of Pacific rats Rattus exulans. Tuatara were housed in predator-proof outdoor enclosures. In 1992–2007, eggs were moved to a separate facility for artificial incubation in dampened vermiculite (see original paper for details). Overall, four clutches were induced and 27 clutches were laid naturally. Hatchlings were returned to their source facility at one week–11 months old. Eggs that perished shortly after being laid (5–16 eggs in two clutches) and eggs laid by artificially-incubated females were excluded from results.
Study and other actions tested
Referenced paper
Keall S.N., Nelson N.J. & Daugherty C.H. (2010) Securing the future of threatened tuatara populations with artificial incubation. Herpetological Conservation and Biology, 5, 555-562.

Please cite as:

Sainsbury K.A., Morgan W.H., Watson M., Rotem G., Bouskila A., Smith R.K. & Sutherland W.J. (2021) Reptile Conservation: Global Evidence for the Effects of Interventions for reptiles. Conservation Evidence Series Synopsis. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Reptile Conservation

Related Actions

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Alter incubation temperatures to achieve optimal/desired sex ratio: Tuatara Action Link	Awaiting assessment	2	Synopsis Link
Release captive-bred reptiles into the wild: Sea turtles Action Link	Awaiting assessment	3	Synopsis Link
Rehabilitate and release injured or accidentally caught individuals: Snakes & lizards Action Link	No evidence found (no assessment)	0	Synopsis Link