[Dataset:] Fine-scale whisker growth dynamics can be used to interpret temporal foraging information from stable isotope signatures. Supporting data and software.

Abstract

Stable isotope analysis of slow-growing, metabolically inert tissues is a common method to investigate foraging ecology in migratory animals, as direct observations of feeding are often not possible. Using tissue growth dynamics to interpret foraging timelines can maximize the utility of foraging data; however, applying inappropriate growth models is problematic and high-resolution growth measurements are seldom made. We used photogrammetry to repeatedly measure the length of whiskers in 93 follicles over 670 days in a trained, captive northern elephant seal (Mirounga angustirostris). We developed and optimized a follicle-specific growth model to describe the 18,000 whisker length measurements. Whiskers from the captive seal exhibited asymptotic growth that was described by the von Bertalanffy growth function. Applying the growth model to serially sampled whiskers from four free-ranging, adult female northern elephant seals resulted in alignment of peaks in δ15N along the length of whiskers with the breeding haul-out period, when seals were not feeding. Our study provides a whisker growth model of the highest resolution for any mammal and is the first to use whisker growth dynamics for temporal interpretation of isotopic ratios......

Supporting information includes graphs showing observed and fitted growth trajectories of all 44 whisker follicles analyzed, the fitted growth parameters for each, and the R source code used for fitting the model. Detailed descriptions of each files content are provided in the files.