Salivary cortisol in captive dolphins (Tursiops truncatus): a non-invasive technique
Dolphins in captivity have to cope with severe changes in their environment. So far, there are few studies on the welfare of these animals under these conditions. The aim of the present study was to find if cortisol was present in the saliva of dolphins and to explore the possibility
of performing serial, non-invasive cortisol assays in captive dolphins. Saliva was collected non-invasively during a month from four dolphins that had responded to previous training, in order to provide saliva samples, in two aquaria in Mexico City. In addition, serum and saliva time-matched
samples were obtained in an aquarium in Nuevo Vallarta, Mexico. Cortisol concentrations in saliva and blood were measured by radioimmunoanalysis (RIA). Results show for the first time that measurable quantities of cortisol are secreted within the saliva of dolphins. Salivary cortisol measurements
could be a useful tool for carrying out long-term cortisol sampling. It is far less invasive than blood-sampling and could be used, in conjunction with behavioural observations, to monitor the welfare of captive dolphins, non-invasively.