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RESEARCH PRODUCT
Cohort-Dependent Sex Ratio Biases in the American Crocodiles (Crocodylus acutus)of the Tempisque Basin
Craig GuyerChristopher M. MurrayMichael EasterSergio PadillaMahmood SasaJulia Ann StoneJuan Bolaños-monteroDavinia B. Garrigóssubject
geographyeducation.field_of_studygeography.geographical_feature_categorybiologyEcologymedia_common.quotation_subjectCrocodylus acutusPopulationDrainage basinZoologyAquatic Sciencebiology.organism_classificationCompetition (biology)CohortJuvenileAnimal Science and ZoologyeducationHatchlingEcology Evolution Behavior and SystematicsSex ratiomedia_commondescription
A male-biased sex ratio of 3:1 has been reported for a population of American crocodiles (Crocodylus acutus) in the Tempisque River Basin, Guanacaste, Costa Rica. If confirmed, this would constitute one of the largest male-biased sex ratios reported for any population of a member of the genus Crocodylus. Here, we examine the aforementioned population of C. acutus and report on sex ratios of hatchling, juvenile, and adult age classes within a sample of 474 crocodiles captured in the Tempisque Basin between May 2012 and June 2014. Hatchling sex ratio is exceptionally male biased (3.5:1), an imbalance that is maintained in juveniles but is reduced in adults (1.5:1). Mark–recapture data document that juvenile males disperse from the study site, potentially to avoid competition, a process that reduces male bias in the adult age class. An increased role of males in human–crocodile conflict may be a result of juvenile males dispersing to human-inhabited areas.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2015-09-01 | Copeia |