When it comes to the conservation of endangered species, such as the big cats (or felids), understanding more about the food being eaten in the wild can be useful. Though it is possible to analyze the dietary intake of animals through analysis of their whiskers, insufficient data on whisker growth rates for different species has thus far got in the way of accurate assessment. Thankfully, five wild cats from the National Zoological Gardens in Pretoria, South Africa have stepped up for the good of their species.
Four lions – Emma, Bianca, Tess and Boesman – and Diesel the leopard valiantly (if not willingly) donated their whiskers for isotopic analysis. The human contingent included researchers from Cape Peninsula University of Technology and the University of the Free State, Bloemfontein. Over a period of 185 days, giraffe meat was added to the wild cats’ staple diet of chicken and beef at four stages, while the animals’ whisker growth was monitored. The whiskers were then removed and segmented, before being analyzed by isotope ratio mass spectrometry (IRMS) to determine nitrogen and carbon ratios. The 13C-depleted, C3-based giraffe meat presented as clear peaks in the ratio plots, correlating in three cases with the feeding bouts (1). Trophic discrimination factors (TDFs) – the isotopic difference between the whisker tissue and the diet – were also taken into account. The conclusion? Big cat whiskers can clearly provide important dietary information – though the authors of the resulting paper (1) noted that TDFs did differ between felid species. They acknowledge that to provide more insight into isotope discrimination, further studies are needed on the full trajectories of whisker growth and shedding, as well as possible life history influences. As for Emma, Bianca, Tess, Boesman and Diesel, despite the undignified plucking of their whiskers, we hear they’re still feline fine…
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References
- R Mutirwara et al., “Growth rate and stable carbon and nitrogen isotope trophic discrimination factors of lion and leopard whiskers”, Rapid Commun Mass Spectrom, 32, 33– 47 (2018).