DOI: 10.5061/dryad.8n241v7
title: Data from: Estimation of energetic condition in wild baboons using fecal thyroid hormone determination

description: Understanding how environmental and social factors affect reproduction
 through variation in energetic condition remains understudied in wild
 animals, in large part because accurately and repeatedly measuring
 energetic condition in the wild is a challenge. Thyroid hormones (THs),
 such as triiodothyronine (T3) and thyroxine (T4), have a key role in
 mitigating metabolic responses to energy intake and expenditure, and
 therefore are considered important biomarkers of an animal's
 energetic condition. Recent method development has shown that T3 and T4
 metabolites can be measured in feces, but studies measuring THs in wild
 populations remain rare. Here we measured fecal T3 metabolites (mT3) in
 baboons, and tested whether the conditions of collection and storage used
 for steroid hormones could also be used for mT3; we focused on mT3 as it
 is the biologically active form of TH and because fecal T4 metabolites
 (mT4) were below detection levels in our samples. We also tested if mT3
 could be determined in freeze-dried samples stored for long periods of
 time, and if these concentrations reflected expected biological variations
 across seasons and reproductive states. Our results show that mT3 can be
 measured with accuracy and precision in baboon feces. The conditions of
 collection and storage we use for steroid hormones are appropriate for mT3
 determination. In addition, mT3 concentrations can be determined in
 samples stored at -20 °C for up to 9 years, and are not predicted by the
 amount of time in storage. As expected, wild female baboons have lower mT3
 concentrations during the dry season. Interestingly, mT3 concentrations
 are lower in pregnant and lactating females, possibly reflecting an energy
 sparing mechanism. Retroactive determination of mT3 concentration in
 stored, freeze-dried feces opens the door to novel studies on the role of
 energetic condition on fitness in wild animals.
description: mT3 concentrations for
 wild baboonsThis dataset was used to
 assess whether seasonal variation in rainfall and female reproductive
 status affected mT3 concentrations in wild baboons. For this analysis we
 used 377 fecal samples from 61 wild adult females. These samples were the
 leftover freeze-dried fecal powder from samples collected between January
 2008 and October 2015 for steroid hormone analyses. The freeze-dried fecal
 powder had been stored at -20 °C for period of time ranging from 1.3 years
 (for the samples collected in October 2015) to 9.1 years (for the samples
 collected in January 2008).Dryad TH
 data.xlsxValidation of fecal
 collection and storageThis dataset was used to
 experimentally test how collection and storage conditions encountered when
 working with wild populations affected mT3 concentrations (See Fig. 1).
 Specifically, using the aliquots collected from the captive baboons, we
 treated the four aliquots as follows. The aliquot without ethanol (aliquot
 1) and one of the aliquots stored in 95% ethanol (aliquot 2) were kept at
 -20°C; the other two aliquots stored in 95% ethanol were kept for 8 hours
 at 4°C (aliquot 3) or at 25°C (aliquot 4) before being stored for 2 weeks
 at 4°C. Aliquot 1 represented optimal conditions of collection and storage
 in a lab setting. Aliquots 2-4 tested aspects of field conditions for
 collection and storage. Specifically, aliquot 2 tested the effect of
 simple ethanol storage on mT3 concentrations. Aliquot 3 and 4 tested field
 conditions in which samples were kept in a cooler containing ice packs
 until return to camp site (aliquot 3) or when samples were kept at ambient
 temperature until return to camp site (aliquot 4).Dryad TH
 validation.xlsx