Asynchronous reproduction in three species of crocodilians in south-eastern Amazonia

ABSTRACT

We studied reproduction of three species of crocodilians, Paleosuchus trigonatus, Caiman crocodilus and Melanosuchus niger, in the Xingu River, near the Belo Monte hydroelectric dam. The periods of laying and hatching of eggs were estimated for each nest before (2013–2014) and after (2016–2017) the river was dammed and the reservoir was formed. Nesting of the three species occurred between August and December, but was largely asynchronous; nest construction peaked in September for P. trigonatus, October for M. niger and November for C. crocodilus. Reservoir filling had little effect on the laying period of any of the species. Nests of P. trigonatus and M. niger were always within 0–12 m of the bank, whereas nests of C. crocodilus, which nests later in the season when flooding is more likely, were up to 100 m from the nearest water body. There was no relationship between distance from water and the number of eggs in nests, suggesting that larger and presumably more experienced females do not lay at different distances from the bank in any of the species.

KEYWORDS:

• Nesting
• Crocodylia
• conservation
• Amazon

Acknowledgements

This work was supported by the Norte Energia, Tractebel Engenharia, Fundação Pantanal Com Ciência and Fundect/CNPq grant PRONEX006/2015. We thank Daniel Martins, Reginey Gomes, Roberto da Costa, Elenilson Silva, Fernando Costa and Sebastião da Gama for their help in finding nests. WEM was supported by a Productivity Grant from CNPq. PPBio-AmOc and INCT-CENBAM provided data-curation facilities. The data are made available in protocols dx.doi.org/10.17504/protocols.io.uaxesfn.

Disclosure statement

This study was supported financially and logistically by a company (Norte Energia) with a vested interest in their construction activities (Belo Monte dam) not impacting wildlife.

Additional information

Funding

This work was supported by the Belo Monte Hydroelectric Dam [10000]; Tractebel Engineering [30000]; Fundação Pantanal Com Ciência [20000].