Nest attendance and hatchling care in wild American crocodiles (Crocodylus acutus) in Quintana Roo, Mexico

摘要

Crocodilians show universal parental care, but few studies concentrate on this behavior in wild crocodiles. We studied nest and hatchling care in genetically pure wild American crocodiles (Crocodylus acutus) on two Caribbean islands of Mexico. From 2006 to 2009 we made direct observations of crocodile behavior upon discovery of nests and groups of hatchlings in Banco Chinchorro. In 2009, we installed camera traps at 4 nests from the time of their discovery to the hatching of each nest, in Banco Chinchorro and Cozumel Island. Twenty-one other species were observed to visit crocodile nests. No nest predation was observed but nine species represented some danger to nests and/or hatchlings. Females seemed to remain in the nest vicinity during incubation. There was variability in nest visit frequencies and no nest defense toward human intrusion was observed. Visit frequency by other species at nests decreased with increased crocodile visitation. Crocodiles mainly visited nests on darker nights, corresponding to the visits of species representing greater danger for nests. Repair of the nest by females after disturbance was observed for the first time in wild American crocodiles. Crocodile visits were more frequent at the beginning and the end of incubation, which could represent different anti-predation strategies. Although adult crocodiles helped during hatching for the emergence of neonates, hatchling care seemed reduced compared to other crocodile species. We provide the first data on nesting behavior of genetically pure American crocodiles in the Yucatan peninsula, which provides a base for future comparisons with Morelet's crocodiles and their hybrids.