Movement Behavior of Manatees and Dugongs: I. Environmental Challenges Drive Diversity in Migratory Patterns and Other Large-Scale Movements

Charles J. Deutsch, Delma Nataly Castelblanco-Martinez, Rachel Groom, Christophe Cleguer

    Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

    Abstract

    The seemingly unhurried nature of manatees and dugongs belies their great capacity for undertaking long-distance journeys, often repeatedly in the form of round-trip seasonal migrations, but sometimes as movements independent of seasonal influence. Unique attributes of sirenian biology that interact with features of their environment to mold patterns of movement and habitat use include herbivory, limited thermoregulatory physiology for coping with cold and, for manatees, an apparent need to ingest fresh water. Manatees and dugongs are remarkably adaptable in their large-scale movement behavior, as manifested by the considerable variation in the occurrence and extent of migrations across populations within species, and among individuals within populations. Some populations and individuals are relatively sedentary year-round, whereas others migrate hundreds of kilometers between seasonal ranges. The environmental selective pressures driving seasonal movements vary across species, climates, and ecosystems, but are most commonly generated by predictable fluctuations in water temperature (Florida manatee, some dugong populations), rainfall (coastal populations of Antillean and African manatees), or water level (inland populations of all 3 manatee species living in flood-pulse river systems) over the annual cycle. In each case there is a season (winter, dry, or low-water) of heightened environmental stress where the animals’ range is restricted to areas around a key limiting resource (warm water, fresh water, or deep water), and forage is therefore less available or of lower nutritional quality. Because dugongs are strictly marine and do not require fresh water, they experience fewer seasonally imposed constraints and are less likely to migrate than manatees. Consequently, the large-scale movements of dugongs seem more stochastic; assessing the status of forage over a wide area through occasional long-distance exploratory forays may represent a behavioral adaptation to periodic extensive declines in seagrass caused by extreme weather events. The available evidence for manatees indicates strong fidelity to seasonal or year-round ranges across years. A common finding from tracking studies is the existence of considerable variation in large-scale movement behavior among and within individuals, which should confer adaptability to environmental change in the short term and provide the raw material for evolutionary change over the long term.
    Original languageEnglish
    Title of host publicationEthology and Behavioral Ecology of Sirenia
    EditorsHelene Marsh
    Place of PublicationCham
    PublisherSpringer
    Chapter5
    Pages155-231
    Number of pages77
    Edition1
    ISBN (Electronic)978-3-030-90742-6
    ISBN (Print)978-3-030-90741-9
    DOIs
    Publication statusPublished - 1 May 2022

    Publication series

    NameEthology and Behavioral Ecology of Marine Mammals (EBEMM)

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