Among the Crocodylia, maternal females of most species are known to attend their nests during the egg incubation period. However, the ecological and environmental factors driving nest attendance in these reptiles remain poorly understood. In 2019, we conducted a study in coastal South Carolina, USA, to examine temporal patterns of nest attendance by American Alligators (Alligator mississippiensis), investigate the site and environmental factors influencing nest attendance, and characterize behaviors exhibited by attending females. We used automated game cameras to monitor American Alligator nests throughout the incubation period and collected a suite of physical and environmental measurements at nest sites and associated habitat. Female attendance was modeled using generalized linear mixed-effects models with a binomial error distribution. Overall, nest attendance occurred for only a brief portion (1%) of the nesting period. The primary factors influencing nest attendance were day since oviposition, time of day, rainfall, and distance of nests to nearest water, with most attendance occurring during the first week postoviposition, at the end of incubation preceding hatchling emergence, at nighttime, shortly following rain events, and when nests were closer to water. Salinity of nearest water exhibited a weak effect, with the probability of nest attendance slightly decreasing as salinity increased. Maternal females exhibited four primary behaviors associated with nest attendance: crawling on the nest (16.2%), guarding the nest from a distance (62.2%), defending the nest (2.5%), and opening the nest and transporting young to water (19.0%), although temporal and behavioral patterns of nest attendance varied among individual females. At 8 (80%) of 10 nests predated by Raccoons (Procyon lotor), the maternal female returned and attempted to repair the nest. Nest defense by female American Alligators was low relative to the number of nest visits by egg and hatchling predators and other mammals. Collectively, our study reveals both environmental and nest site–level factors influence female nest attendance and, more broadly, demonstrates the importance of spatial and temporal scales of observation in studies of crocodilian maternal care.
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31 January 2025
Nest Attendance by American Alligators (Alligator mississippiensis) in Coastal South Carolina
Thomas R. Rainwater,
Randeep Singh,
Samantha L. Bock,
Philip M. Wilkinson,
Steven G. Platt,
Bo Song,
Catherine M. Bodinof Jachowski
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Herpetologica
Vol. 81 • No. 1
March 2025
Vol. 81 • No. 1
March 2025
Automated game camera
behavior
crocodilian
maternal care
nesting ecology