News Release

New study indicates pressing conservation questions for Crocodilian researchers

Future study should provide answers to 'knowledge gaps' about reptiles' ecological role

Peer-Reviewed Publication

San Diego Zoo Wildlife Alliance

On land and in salt water environments, large predators like lions and sharks maintain the delicate balance of their ecosystems, keeping the population of their prey species in check--and how they do it is well documented by scientific research. However, much less is known about the importance of crocodilians to the health of their freshwater environments.

An extensive literature review recently published in the journal Biological Reviews takes stock of existing knowledge relating to the role these predators play in stabilizing aquatic ecosystems, with far-reaching conservation implications. The study was authored by 17 researchers from institutes spanning the globe from Louisiana to Australia, Denmark and Myanmar. San Diego Zoo Global has supported the research and field work of several of the authors through grants and other means in its efforts to conserve crocodilians.

"You don't usually see a paper with so many authors, but we've all worked together as a global community, supporting and partnering with each other to learn more," said Kim Gray, curator of herpetology and ichthyology at the San Diego Zoo. Notably, the study found significant "knowledge gaps," and identified key areas on which future research should focus. "We do know some things about the importance of crocodilians in their environment, but we want to promote more research," Gray said.

In addition to research and field work, San Diego Zoo Global supports the conservation of crocodilians by participating in Species Survival Plan programs administered through the Association of Zoos and Aquariums (AZA), and maintaining studbooks for threatened and endangered species. Nearly all of the six crocodilian species at the San Diego Zoo have a Species Survival Plan, a 100-year strategy for maintaining genetic diversity.

Worldwide, there are 28 species of crocodilians, an order including alligators, crocodiles, caimans and gharials. Unfortunately, many of them--and their habitats--face severe threats. Nearly one third are listed as Critically Endangered on International Union for Conservation of Nature's (IUCN) Red List of Threatened Species--more than in any other taxonomic group.

Though data is lacking, researchers believe crocodilians can indeed mirror ecosystem health, serve as a measure of conservation and management efforts, and provide many other important ecological functions. The authors called on researchers to focus future efforts on understanding three essential factors of crocodilian ecology: population dynamics, feeding and nutrition dynamics, and the impact of their decline or local extinction.


About San Diego Zoo Global

Bringing species back from the brink of extinction is the goal of San Diego Zoo Global. As a leader in conservation, the work of San Diego Zoo Global includes on-site wildlife conservation efforts (representing both plants and animals) at the San Diego Zoo, San Diego Zoo Safari Park, and San Diego Zoo Institute for Conservation Research, as well as international field programs on six continents. The work of these entities is made accessible to over 1 billion people annually, reaching 150 countries via social media, our websites and the San Diego Zoo Kids network, in children's hospitals in 12 countries. The work of San Diego Zoo Global is made possible with support from our incredible donors committed to saving species from the brink of extinction. To learn more, visit or connect with us on Facebook.

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