Geographic variation in vocalizations of pups and mother-pup behavior of harp seals Pagophilus groenlandicus

Abstract

All harp seal populations form breeding aggregations on the Arctic pack ice. However, pack ice conditions vary spatially and temporally among these aggregations with variation in environmental and oceanographic conditions, which may affect the behavioral interactions between mothers and their newborn pups. We investigated the variation in mother-pup behavior between harp seal breeding aggregations in the NE (Greenland Sea) and NW Atlantic coastal shelf region (Front). Acoustic cues provided by the pups are thought to be important in facilitating reunions with their mothers. Consequently, we measured variation in vocal parameters among seals to investigate geographic differences in pup vocalizations. Classification trees showed a distinctive split between Front and Greenland Sea pup vocalizations. There were no clear differences between male and female pups at the Front, where 42% of male and 38% of female pup calls could be attributed to a given individual. This contrasts with the Greenland Sea, where 55% of vocalizations of female pups were attributed to individuals compared with only 8% for males. Analyses of behavioral observations of mother-pup pairs made in the afternoon and evening showed that pups in the Greenland Sea suckled more and were more alert than pups in the Front. Further, mother-pup attendance patterns differed between sites. Mothers at the Front attended their pups 85.1% of the time, whereas mothers in the Greenland Sea attended their pups 52.2% of the time. These substantial differences between sites might be related to evolutionary changes in behavior resulting from commercial hunting or variable environmental conditions.

Year-round acoustic detection of bearded seals (Erignathus barbatus) in the Beaufort Sea relative to changing environmental conditions, 2008–2010

“…Expanding the study to the Bering and Chukchi Seas will cover much of the range of Alaskan bearded seals and provide a broader picture of their seasonal occurrence under the different ice conditions they experience over this range. Finally, detailed analysis of call types can be used to determine whether or not geographic variation exists among the three seas as has been shown in other regions and with other species (Van Parijs et al 1999;Bjørgesaeter et al 2004;Risch et al 2007;Van Opzeeland et al 2009). There are potential subpopulations that reside in each region throughout the year that may be determined by comparing call types present throughout the year at each location.…”

Individual signatures in the vocal repertoire of the endangered Mediterranean monk seal: new perspectives for population monitoring

“…However, a less complex task aiming to classify individuals using their vocalizations can be done by performing acoustic statistical analyses without testing animals. Such 'passive' individual classifications have been performed on many pinnipeds, with both aerial and underwater calls of mother−pup pairs and males (Insley et al 2003, Collins et al 2005, Charrier & Harcourt 2006, Khan et al 2006, Van Parijs & Clark 2006, Risch et al 2007, Gwilliam et al 2008, Van Opzeeland et al 2009, Charrier et al 2010, Trimble & Charrier 2011, Sauvé et al 2015.…”

Individual variation in pup vocalizations and absence of behavioral signs of maternal vocal recognition in Weddell seals (Leptonychotes weddellii)

“…, McMurdo Sound 50–100 Weddell seal mother–pup pairs). Differing environmental factors between populations such as local ice conditions or breeding colony density can therefore not be excluded to affect the relative contribution of the different sensory modalities for successful mother–pup reunions, leading to population or breeding colony differences in mother–pup behavior (McCulloch and Boness 2000, Van Opzeeland et al 2009).…”