Social and Reproductive Behaviors

Abstract

Sirenian social and reproductive behaviors lack much complexity or diversity. Whereas sirenians are usually sighted as solitary, or as cows with single calves, aggregationsAggregation of many individuals can occur. Persistent social groupings are unknown. Home ranges are widely overlapping. Mating systems of dugongsDugong (Dugong dugon) (Dugong dugon) have been variously described as leks or as scramble promiscuityScramble promiscuity (mating herdsMating herd) and lone mating pairs have been observed in areas of low density, but further research into the hypothesized leks is needed (especially because scramble promiscuityScramble promiscuity has been observed in the same region). DugongsDugong (Dugong dugon) and all manateesManatee (Trichechus) show scramble promiscuityScramble promiscuity, wherein malesMales form groups that escort single females with much physical contact for many days. The strongest social bonds are between females and nursingNursing calves. Florida manateesFlorida manatee () (Trichechus manatus latirostris) show natal philopatryNatal philopatry for years after weaningWeaning. Socially transmitted knowledgeSocially transmitted knowledge (traditionTradition) appears important to Florida manateesFlorida manatee () and perhaps all species of sirenians, particularly in regions where seasonal movementsSeason/ seasonal movements during winter are necessary for survival, such as in winter for Florida manateesFlorida manatee (), and dugongsDugong (Dugong dugon) at the high latitude limits of their range. Some populations of Antillean, Amazonian, and African manateesAfrican manatee (Trichechus senegalensis) have regular movements in response to seasonal flooding and access to foodFood, which also may be learned through traditionTradition . DugongsDugong (Dugong dugon) may rely on group movements based on traditional knowledge in response to regional lossLoss, of foodFood supply from extreme weather eventsExtreme weather events. Communication is most obvious through vocalizationsVocalizations, which can show individual distinctiveness. Vocal communicationVocal communication is most prevalent between mothers and calves. Allomaternal careAllomaternal Care occurs in Florida manateesFlorida manatee () at shared aggregationAggregation sites. Florida manateesFlorida manatee () occupying a given region can consist of multiple matrilines that develop through the early bonding of calves to mothers and subsequent natal philopatryNatal philopatry. Population geneticsPopulation genetics research supports maleMales-biased dispersalDispersal and possible female-based philopatry in other trichechids, but perhaps not as strongly in dugongids. Considerable further research is needed on these and related topics to more comprehensively understand sirenian social and reproductive behavior.

Topics & Concepts