title: Spatial variation in age structure among colonies of a marine snake: the influence of ectothermy.
abstract: Several tetrapod lineages that have evolved to exploit marine environments (e.g. seals, seabirds, sea kraits) continue to rely upon land for reproduction and, thus, form dense colonies on suitable islands. In birds and mammals (endotherms), the offspring cannot survive without their parents. Terrestrial colonies contain all age classes. In reptiles (ectotherms), this constraint is relaxed, because offspring are independent from birth. Hence, each age class has the potential to select sites with characteristics that favour them. Our studies of sea snakes (sea kraits) in the lagoon of New Caledonia reveal marked spatial heterogeneity in age structure among colonies. Sea krait colonies exhibit the endothermic 'seal-seabird' pattern (mixed-age classes within populations) only where the lagoon is narrow. Where the lagoon is wide, most snake colonies are comprised primarily of a single age cohort. Nurseries are located near the coast, adult colonies offshore and mixed colonies in-between. We suggest that ectothermy allows individuals to utilize habitats that are best suited to their own ecological requirements, a flexibility not available to endothermic marine taxa with obligate parental care.
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372-CNRS Université de La Rochelle, Villiers-en-Bois, 79360, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Bonnet
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372-CNRS Université de La Rochelle, Villiers-en-Bois, 79360, France.
authors.forename: François
authors.initials: F
authors.lastname: Brischoux
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372-CNRS Université de La Rochelle, Villiers-en-Bois, 79360, France.
authors.forename: David
authors.initials: D
authors.lastname: Pinaud
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372-CNRS Université de La Rochelle, Villiers-en-Bois, 79360, France.
authors.forename: Catherine Louise
authors.initials: CL
authors.lastname: Michel
authors.affiliation: Station d'Ecologie Expérimentale du CNRS à Moulis USR 2936,  Moulis, Saint-Girons, 09200, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Clobert
authors.affiliation: School of Biological Sciences A08, University of Sydney, Sydney, NSW, 2006, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Shine
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UMR 7372-CNRS Université de La Rochelle, Villiers-en-Bois, 79360, France.|Université Pierre et Marie Curie, Paris, 75005, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Fauvel
mesh_terms: D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D049628:Body Size; D001833:Body Temperature Regulation; D003710:Demography; D017753:Ecosystem; D017815:Elapidae / Q000502:physiology*; D005260:Female; D008297:Male; D009510:New Caledonia
keywords: Laticauda; colony; dispersal; marine tetrapods; population; sea snakes