Crocodiles

Edited by James Perran Ross

IUCN/SSC Crocodile Specialist Group

Contributors:

Eduardo Espinosa (Caiman crocodilus, C. yacare)
B.E.E.C.S. Laboratory, University of Florida
Gainesville, FL 32611, USA

Robert Godshalk (Paleosuchus palpebrosus. P. trigonatus)
Department of Wildlife Ecology and Conservation
University of Florida
Gainesville, FL 32611, USA

Philip Hall (Crocodylus novaeguineae)
Environmental Office, Camp Blanding
Dept. Military Affairs, FLARNG
Starke, FL 32091-9703, USA

John Thorbjarnarson (Crocodylus intermedius, Melanosuchus niger)
Wildlife Conservation Society – NYZS
185th Street and Southern Blvd., Bronx, NY 10460, USA

Anton Tucker (Crocodylus johnsoni)
Department of Zoology, University of Queensland
Brisbane 4072, Australia

Luciano Verdade (Caiman latirostris)
Departo Zootechnica/ESALQ
Universidad de Sao Paulo, Piracicaba, Brazil

Cover photo: Black caiman, Melanosuchus niger, Mamiraua, Brazil, where a substantial population of this depleted species is reported to be recovering. Photo by J. Thorbjarnarson.

• Suggested Citation & Printed Edition
• Executive Summary
• Foreword
• Acknowledgements
• Objectives and Organization
• Introduction
  • Crocodilian biology
  • Threats to crocodilians
  • Conservation strategies for crocodilians
• Conservation Priorities
  • Priority analysis
  • Projects listed in order of priority, highest to lowest
• Species Accounts
  • Alligator mississippiensis American alligator
  • Alligator sinensis Chinese alligator
  • Caiman crocodilus Common caiman
  • Caiman latirostris Broad-snouted caiman
  • Caiman yacare Yacaré
  • Melanosuchus niger Black caiman
  • Paleosuchus palpebrosus Dwarf caiman
  • Paleosuchus trigonatus Smooth-fronted caiman
  • Crocodylus acutus American crocodile
  • Crocodylus cataphractus Slender-snouted crocodile
  • Crocodylus intermedius Orinoco crocodile
  • Crocodylus johnsoni Australian freshwater crocodile
  • Crocodylus mindorensis Philippine crocodile
  • Crocodylus moreletii Morelet’s crocodile
  • Crocodylus niloticus Nile crocodile
  • Crocodylus novaeguineae New Guinea crocodile
  • Crocodylus palustris Mugger
  • Crocodylus porosus Saltwater crocodile
  • Crocodylus rhombifer Cuban crocodile
  • Crocodylus siamensis Siamese crocodile
  • Osteolaemus tetraspis Dwarf crocodile
  • Tomistoma schlegelii Tomistoma
  • Gavialis gangeticus Gharial
• References
• Appendix 1. Vernacular and Trade Names for Crocodilians of the World
• Appendix 2. IUCN Red List Categories

The revised Action Plan for Crocodiles, provides concise summaries of the current status and recent information for all 23 species of crocodilian. The Action Plan supersedes the 1992 Crocodiles: An Action Plan for their Conservation. It reflects the ongoing activities of the Crocodile Specialist Group (CSG) membership, provides some guidance and describes priorities for immediate actions that address the most pressing current problems in crocodilian conservation.

An introductory section provides general information on crocodilian biology and outlines some general principles that are being applied to their conservation. The ecological and economical importance of crocodilians in their wetland habitats is noted. Conservation of wild crocodilian populations has numerous spin-off benefits for other species and local human communities. The application of sustainable use to crocodilian conservation is explained, and descriptions of national programs that demonstrate both the application and the effectiveness of these methods are included. The examples of the American alligator in the USA, the Nile crocodile in Zimbabwe and South Africa, and the Saltwater crocodile in Australia and Papua New Guinea are particularly compelling.

This revised Action Plan provides the first application of the new 1994 IUCN Red List Categories to crocodilian status assessment. In general, the assessments made using the 1994 categories agree with previous assessments, but in several cases the application of the new objective and quantitative criteria has drawn our attention to some significant gaps in our information and the need for a reconsideration of species status. The Critically Endangered status of Crocodylus mindorensis, Crocodylus siamensis, Alligator sinensis and Crocodylus intermedius is confirmed and these remain the highest priority for action. Three species, Tomistoma schlegelii, Crocodylus moreletii and Crocodylus cataphractus were evaluated to be Data Deficient. New information suggests Tomistoma may be Vulnerable and C. moreletii Lower Risk, conservation dependent. The application of the quantitative criteria and new information on status reassures us that Crocodylus rhombifer, Gavialis gangeticus and Melanosuchus niger are all showing slow recovery but remain Endangered. The maintenance of ongoing conservation action on these species should continue their recovery. Crocodylus acutus, Crocodylus palustris and Osteolaemus tetraspis are evaluated as Vulnerable. The remaining ten species of crocodilian are assessed to have a Lower Risk of extinction. This group includes the major species appearing in trade and subject to sustainable use and management.

The revised Action Plan provides an updated set of action recommendations for each species. The recommended actions include: status surveys, the identification and protection of important populations and habitat; the enhancement of conservation and management capacity of national authorities; the development of national management plans for crocodilian conservation; captive breeding and restocking programs; and the development of economic incentives for crocodilian conservation through well-regulated sustainable use. Those high priority projects applying to the most endangered species are analyzed and ranked as a guide to immediate needs.

The plan provides government agencies, management authorities, funding agencies, researchers, non-governmental organizations and other conservation interests with basic information and concrete recommendations for action that will promote the conservation of crocodilians and their habitats.

When Crocodiles: An Action Plan for their Conservation was completed and went to press in 1990 we did not truly expect that so many of the facts and recommendations it contained would become obsolete within a short time. To our surprise, and considerable pleasure, such is the case. The period 1990–1997 has seen some tremendous advances in our knowledge of the status of crocodiles and some significant improvements in the status of some species. The overall strategy of the CSG appears to be effective in slowing, and then reversing declines in the various species, and in encouraging proactive conservation programs to ensure their continued survival.

This period has not been without controversy and some setbacks. The CSG’s enthusiastic promotion of sustainable use has drawn criticism from some quarters, largely by those who are unaware of, or cannot bring themselves to believe, its demonstrated success. In this period we have also engaged in an extended debate over the relative conservation merits of various forms of sustainable use for crocodilians (ranching, closed-cycle farming and wild harvest) and this Action Plan addresses the advantages, disadvantages, and some important general cautions applying to each. We have also continued to assist and promote a variety of other conservation mechanisms, including complete protection, captive breeding and restocking. Our commitment to the conservation of wild populations of all species of crocodilians remains undiminished and we will recommend all the available techniques and strategies to achieve success. This task is far from complete but we understand that conservation is a dynamic process that will require continued action.

The Crocodile Specialist Group draws its strength and its effectiveness from its members. Their individual contributions, summed over the numerous countries and projects in which they are involved, provides the information and action which this Action Plan outlines. This revised Action Plan, like its predecessor, is intended to be a dynamic document that will be revised again to reflect changing conditions and knowledge. It provides a concise and focused guide to the status of crocodilians and the current actions needed for their conservation and will be a general guide to our activities for the forthcoming period.

Professor Harry Messel
Chairman, IUCN/SSC Crocodile Specialist Group

This work could not have been completed without the financial support generously provided by Utai and Uthen Youngprapakorn and the Samutprakan Crocodile Farm and Zoo. The editor wishes to thank the contributors who provided drafts for the revision of several of the accounts, but retains the full responsibility for the final content and any errors. Professor Harry Messel, CSG Chairman, provided the initial stimulus for revising the Action Plan and continued to provide a firm pressure that ensured its completion. John Polisar and Sylvia Scudder contributed valuable support and comments. The working draft was reviewed by Dennis David, Phil Hall, Jon Hutton, Dietrich Jelden, F. Wayne King, Grahame Webb, Hank Jenkins, Alvaro Velasco, Lala Singh, David Evans, Enrico Chiesa, Norm Scott, Andreas Schubert, Chris Banks, Mark Bezuijen, Walt Rhodes, Indraniel Das, Gustavo Hernandez, Zilca Campos, Myrna Watanabe, Alan Woodward, Paul Ouboter, and Charles A. Ross. Copy-editing and production assistance was provided by Alexandra Zimmermann. Finally, it is a pleasure to acknowledge the immense contributions of dozens and dozens of CSG members, who by their day-to-day efforts and particularly their communications with the CSG, keep us active and informed about the progress of crocodilian conservation throughout the world. Their work is the firm basis on which the Action Plan is securely grounded.

James Perran Ross, Editor.
Executive Officer CSG

In the executive summary of Crocodiles: an Action Plan for their Conservation (1992) the following passage appears;

“The seven most critical species in terms of need for conservation are, in order of priority: the Siamese crocodile (Crocodylus siamensis), the Philippine crocodile (Crocodylus mindorensis), the Chinese alligator (Alligator sinensis), the Cuban crocodile (Crocodylus rhombifer), the tomistoma (Tomistoma schlegelii), the Orinoco crocodile (Crocodylus intermedius), and the gharial (Gavialis gangeticus). Four other species are endangered, the broad-snouted caiman (Caiman latirostris), the black caiman (Melanosuchus niger), the American crocodile (Crocodylus acutus), and Morelet’s crocodile (Crocodylus moreletii). Because so little is known about many of these species, emphasis is placed on conducting population surveys to quantify the current population status as a first step towards initiating conservation programs.”

In the period following the publication of Crocodiles: An Action Plan for Their Conservation, i.e. 1992–1995, considerable progress was made on addressing the conservation needs of the priority species. In the same period the status of the other species also changed. These changes were most clearly demonstrated in the papers presented at the Second Regional Meeting of the CSG in Darwin, Australia, March 1993, the 12th and 13th Working Meetings of the CSG in Pattaya, Thailand, May 1994, and Santa Fe, Argentina, May 1996. Additional new information was published in numerous project reports, publications and CSG reports, some published (e.g. Crocodile Conservation Action 1993) and others distributed in both the formal and popular literature. For some species, better information is allowing us to make more effective decisions for conservation, while for others conservation actions have shown beneficial effects. In a few, the situation continues to be bleak. In all cases it is clear that the Action Plan served its purpose as a catalyst for action and a guide for priorities. The situation has, therefore, sufficiently changed that it is useful to revise the Action Plan to reflect new status and altered priorities as they appear to the CSG at the present time.

We therefore undertook a revision of the Crocodile Action Plan with two main goals:

– To update the available information to indicate the current situation.
– To focus the recommended and priority actions for conservation more clearly.

The original Action Plan was intended to be a dynamic working document. This revision and future revisions continue to reflect the changing nature of the status of crocodilians and the changing requirements for their conservation.

The fundamental goal of the CSG remains unchanged, to prevent the extinction of all crocodilians and to encourage management and conservation of crocodilians and their habitats at levels that ensure their ecological integrity and preserve their resource value.

Common caiman (Caiman crocodilus) and capybara
(Hydrochaeris hydrochaeris) in Masaguaral ranch,
Venezuela. Sustainable use of wildlife provides valuable
economic returns to owners of llanos wildlife.
Photo by R. Godshalk.

The objectives of this action plan are to:
1. Summarize new information on the current status of wild crocodilian populations;
2. Summarize new information on current management programs;
3. Assign priorities to species in terms of the need for conservation action; and
4. Develop a list of priority conservation projects for each species.

With these objectives the Action Plan serves the dual purposes of assisting government bodies, local conservation groups and researchers to define their crocodile conservation needs, and to stimulate and support fundraising for priority projects.

Information on population status and management programs was gleaned from published sources, unpublished reports, and from direct communications with CSG members and correspondents. Some of the accounts were drafted by individuals who are listed as the revisers and most of the accounts, and the organization of the whole document, was directed by the editor. The priority conservation programs were projects recommended by CSG members, either specifically for this Action Plan or as recommendations in published or unpublished reports, or were projects deemed to be of particular importance by the editor and revisers. Not all conservation recommendations could be incorporated as specific projects, rather the intent was to address the principal areas of conservation concern and outline, in a very broad sense, what needs to be accomplished. The most immediate priorities are ranked based on urgency. These projects represent an inventory of conservation needs; the details regarding project personnel, budget and timetables are left for future elaboration. A list of people to contact for each project, country or species needs to be developed.

The revised Action Plan follows King and Burke (1989) in recognizing 23 species of crocodilian, although where there is taxonomic confusion or revision in progress this is indicated in the species account. We have generally used the scientific binomial names for crocodilians rather than common names. The scientific names are unique, unambiguous and internationally recognized, while each species has a plethora of common and colloquial names that can cause great confusion. We have inserted some common names to orient the lay reader. A full review of nomenclature of crocodilians is given in King and Burke (1989). An exhaustive list of common, vernacular and trade names is given in the CITES Identification Guide-Crocodilians 1995, Appendix 1.

Yacaré, Caiman yacare. Cooperative group feeding. Crocodilians have a complex social
structure that is poorly understood. Photo by C. Yamashita.