DOI: 10.5061/dryad.v6wwpzh4q
title: Estradiol and creatinine values of captive female bonobos

description: Estradiol is known to have a variety of biological and behavioral effects,
 but monitoring its function is complex given the many factors influencing
 its variation. This necessitates large sample sizes which are challenging
 in captive and wild situations. This study validates the use of
 opportunistically collected urinary estradiol levels (E2) for use in
 reproductive monitoring and behavioral research in bonobos (Pan paniscus).
 We analyzed frozen urine samples from four Columbus Zoo adult females over
 four years for estradiol and creatinine concentrations (n=117). While E2
 was significantly higher in pregnant vs. non-pregnant females (F=66.30,
 df= 1, p&lt;0.001) it was not significantly different between
 lactating and regularly cycling females (F=0.40, df= 1, p=0.5304). Among
 the regularly cycling females, there was a significant positive regression
 between E2 and sexual swelling size (F= 4.43, df=1,81, p=0.0384). No
 differences in E2 variation were detected between individuals in this
 study. Specifically, when the amount of variation in estradiol due to
 sexual swelling was statistically controlled for, there was no significant
 effect of age (n=83, r=0.08059, p=0.4689) or rank (n=83, r=0.1361, p=0.22)
 on estradiol variation. Overall, these findings indicate that
 opportunistically sampled urinary estradiol can be paired with visual
 observation to help detect changes in reproductive status. The shift from
 lactational amenorrhea back to estrogen cycling may be less clearly
 defined than expected, and uneven sampling may exacerbate difficulty in
 detecting some of the more subtle shifts in estradiol levels. While it is
 known that extended maximal tumescence in bonobos may function to obscure
 the exact date of ovulation, we did confirm that ratings of visual
 tumescence still provide useful information regarding relative estradiol
 levels. By publishing more methodologies and results of this kind, we hope
 to promote the continued study of estradiol in bonobos as it is relevant
 to both health monitoring and behavioral research goals.
description: Subjects for this study included four adult female bonobos housed
 at the Columbus Zoo and Aquarium (CZA) in Columbus, Ohio, USA. Samples
 were collected for these individuals during the summer months of 2012,
 2013, 2014, and 2015. Urine samples were collected by CZA staff either by
 using a free catch method in which individual subjects urinated through
 the mesh caging directly into a collection cup, or, by pipetting urine
 directly off a clean floor surface into a plastic cryo-tube. All subjects
 had received previous training to urinate on command in exchange for a
 small food reward.  Upon collection, samples were
 immediately frozen and stored at -20°C until they were packed on dry ice
 and shipped overnight to the Global Health Biomarker Lab at the University
 of Oregon in Eugene, OR where they were stored at -80°C until time of
 analysis.  For analysis, samples were brought to room
 temperature and diluted (1:4) in assay buffer supplied in the 96-well
 Detect X<strong>®</strong> Estradiol ELISA Kit from Arbor
 Assays™ (catalog no. K030-H) and assayed according to the kit
 manufacturer’s instructions. The manufacturer of this kit reported the
 detection limit for this assay as 39.6 pg/mL. This Arbor Assays ELISA
 protocol is validated for use with urinary samples as well as with human
 and animal models. Each plate allows for 40 samples to be run in
 duplicate. To control for variation in the amount and
 concentration of urine samples, all samples were assayed for creatinine
 concentrations using DetectX<strong>®</strong> Urinary
 Creatinine Detection Kits from Arbor Assays™ (catalog no. K002-H). The
 manufacturer listed the detection limit for this assay as 0.019 mg/dL.
 Samples run for creatinine were diluted (1:20) and run according to the
 kit manufacturer’s instructions. All plates were read using a BioTek™
 microplate reader and analyzed with Gen5™ software version 2.0.
 Of the frozen urinary samples available, we were able to assay a
 total of 31 samples from Ana Neema, 16 from Lady, 48 from Susie, and 22
 from Unga for a total of 117 samples. The estradiol concentration values
 obtained from these assays were corrected for creatinine concentration by
 dividing the estradiol concentration value of each sample by its
 respective creatinine value. 
description: # Bonobo Estradiol Data
 [https://doi.org/10.5061/dryad.v6wwpzh4q](https://doi.org/10.5061/dryad.v6wwpzh4q) ## Description of the data and file structure This data contains demographic information for four female bonobos housed at the Columbus Zoo between 2012 and 2015 including age, rank, and reproductive status. Urine samples collected from these females were used to calculate estradiol and creatinine values for each sample. This data was collected for use in a UO graduate student's masters paper in which the validity of monitoring estradiol from opportunistically collected bonobo urine samples for use in reproductive monitoring and behavioral endocrinology studies was assessed.  ### Files and variables #### File: scottondata2.csv **Description:** Data set for assessment of estradiol levels in captive females bonobos housed at the Columbus Zoo between 2012 and 2015.  ##### Variables * Individual (Abbreviation= names of bonobo subjects) * AN= Ana Neema, S=Susie, U=Unga, L=Lady * SampleID (Unique ID number given to urine samples)  * Time (whether sample was collected in the morning or afternoon)  * Morning=before 12pm, Afternoon=after 12pm  * Date (the month of sample collection) * Year (the year of sample collection)  * Swelling (a 0-3 rating of the bonobo's visual sexual swelling size provided by zoo staff)  * 0= smallest swelling size, 3=largest swelling size  * Menstruating (whether the bonobo was visually menstruating when sample was collected)  * 0= not visually menstruating, 1=visually menstruating * Rank (social rank status as determined by previous publications)  * 1=highest social rank, 4=lowest social rank  * Status (reproductive status of individual when sample was taken)  * Parous= not pregnant, not lactating, Lactating=still nursing an infant (generally within 24 months after birth), Pregnant (actively pregnant as confirmed by zoo veterinary staff)  * Age (age at time of sample collection)  * Estradiol (pg/mL, raw concentration value of estradiol collected from Arbor Assays ELISA kit)  * CorrectedEstradiol (estradiol value for sample divided by its respective creatinine value)  * Creatinine (pg/mL, raw concentration of creatinine collected from Arbor Assays ELISA kit)  * '-' dash in database indicates that information was unavailable/not collected