The authors are retracting this article because an error in the reported methodology of this study was found when a follow up investigation of gorilla oxytocin was undertaken. The methods section of this article reports that an extraction step was used in preparing the urine and saliva samples for assay; however, a critical step in the extraction process was mistakenly omitted. The data reported here thus represent a validation of unextracted samples and not of extracted samples. Additional analysis is currently being conducted to understand how the unextracted samples compare to extracted samples and we will submit a new manuscript for review when this has been completed. All authors agree with this retraction.
The online version of this article contains the full text of the retracted article as electronic supplementary material.