Prolonged maternal investment in northern bottlenose whales alters our understanding of beaked whale reproductive life history ...
Nursing and weaning periods are poorly understood in cetaceans due to the difficulty of assessing underwater behaviour in the wild. However, the onset and completion of weaning are critical turning points for individual development and survival, with implications for a species life history including...
| Main Authors: | , , , |
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| Format: | Dataset |
| Language: | English |
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Dryad
2020
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.5061/dryad.k98sf7m3j https://datadryad.org/stash/dataset/doi:10.5061/dryad.k98sf7m3j |
| Summary: | Nursing and weaning periods are poorly understood in cetaceans due to the difficulty of assessing underwater behaviour in the wild. However, the onset and completion of weaning are critical turning points for individual development and survival, with implications for a species life history including reproductive potential. δ15N and δ13C deposited in odontocete teeth annuli provide a lifetime record of diet, offering an opportunity to investigate variation and trends in fundamental biology. While available reproductive parameters for beaked whales have largely been inferred from single records of stranded or hunted animals and extrapolated across species, here we examine the weaning strategy and duration of nursing in northern bottlenose whales (Hyperoodon ampullatus) by measuring stable isotopes deposited in teeth growth layer groups (GLGs). Using a collection of H. ampullatus teeth taken from whales killed during the whaling era (N = 48) and from two stranded specimens, we compared ontogenetic variation of ... : Materials and methods Tooth collection and dentine sampling Teeth were taken from H. ampullatus killed by Norwegian whalers in the waters off northern Iceland in 1967 and northern Labrador in 1971 [27] (Fig 1). Northern bottlenose whales are usually found in groups of one to four, and whalers would take all the whales they encountered, regardless of sex or age class, so we assume our dataset has low demographic capture bias [21]. Individuals included in this analysis ranged from 4-27 years old (median age = 14). The teeth of two H. ampullatus that stranded in northeast Newfoundland in 2004 were also analyzed. The jaws of whaled specimens were originally boiled for two hours to facilitate tooth extraction [27]. Teeth were sectioned along the longitudinal midline and stored unpreserved at room temperature in individual sachets for over 40 years prior to this study. Genetic analysis of gum-tissue from the teeth used in this study confirmed the sex documented in the whaling records [28,29]. The teeth from ... |
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