Translocate adult or juvenile reptiles: Crocodilians

How is the evidence assessed?
  • Effectiveness
    not assessed
  • Certainty
    not assessed
  • Harms
    not assessed

Study locations

Key messages

  • Two studies evaluated the effects of translocating crocodilians on their populations. Both studies were global.



  • Abundance (2 studies): Two global reviews reported four of five crocodilian translocations and 15 of 47 reptile translocations resulted in stable or growing populations (included both wild-caught and captive bred animals).
  • Reproductive success (2 studies): One global review reported that breeding occurred in at least two of five crocodilian translocations (included both wild-caught and captive bred animals).


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

  1. A review of worldwide translocation programmes for reptiles during 1962–1990 (Dodd & Seigel 1991) found that four of five translocations of crocodilians were considered successful by providing evidence that a stable breeding population had been established. Four translocations of four species were considered successful (American alligator Alligator mississippiensis, mugger Crocodylus palustris, saltwater crocodile Crocodylus porosus, and gharial Gavialis gangeticus) and the success of the other translocation was unknown (Nile crocodile Crocodylus niloticus). Breeding was noted in two of the translocation programmes (American alligator and gharial). The origin of individuals (wild populations or captive-bred) was not described for all programmes. Published and unpublished literature was searched.

    Study and other actions tested
  2. A review of worldwide reptile translocation projects during 1991–2006 (Germano & Bishop 2009) found that a third were considered successful with substantial recruitment to the adult population. Of the 47 translocation projects reviewed (39 reptile species), 32% were successful, 28% failed and long-term success was uncertain for the remaining 40%. Projects that translocated animals due to human-wildlife conflicts failed more often (63% of 8 projects) than those for conservation purposes (15% of 38) and those for research purposes (50% of 5). Success was independent of the source of animals (wild, captive, and combination), life-stage translocated, number of animals released and geographic region (see original paper for details). Translocated animals were adults in 75% of cases, juveniles and sub-adults in 64% of cases and eggs in 4% of cases. Wild animals were translocated in 93% of projects. The most common reported cause of failure was homing and migration with the second most common reported cause being insufficient numbers, human collection and food/nutrient limitation all equally reported. Success was defined as evidence of substantial recruitment to the adult population during monitoring over a period at least as long as it takes the species to reach maturity. 

    Study and other actions tested
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?

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Reptile Conservation

This Action forms part of the Action Synopsis:

Reptile Conservation
Reptile Conservation

Reptile Conservation - Published 2021

Reptile synopsis

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