Calf Chronology of the Franciscana Dolphin (Pontoporia blainvillei): Birth, Onset of Feeding, and Duration of Lactation in Coastal Waters of Argentina

摘要

Birth, lactation, and maternal investment have been described and measured in many species of terrestrial and marine mammals that nurse their young on land such as pinnipeds, aquatic mustelids, and polar bears (Siniff & Ralls, 1991; Derocher & Stirling, 1995; Trillmich & Weissing, 2006). Because of their fully aquatic life cycle, information about the early stages of life history in cetaceans is very limited. Most of the information is based on captive individuals of a few species such as the bottlenose dolphin (Tursiops trun-catus) (West et al., 2007), the beluga (Delphinapterus leucas) (Robeck et al., 2005), or by indirect measures (i.e., postmortem data from pregnant females) from fetuses and/or from reproductive parameters of adults of several species (Perrin et al., 1977; Kasuya & Brownell, 1979; Lockyer et al., 2001; Murphy et al, 2009). Also, information on mother-calf associations has been obtained from photo-identification techniques (Grellier et al., 2003).