Assessment of the hormonal status in animals has been carried out in recent decades not only in the blood and organs, but also in various excretions (feces, urine, saliva, milk, hair). Validation of measurements of steroid hormone concentrations in hair is rare, but in recent years this analysis has become more routine. Unlike many other substrates, it is still quite difficult to estimate the time interval that corresponds to the concentration of the hormone in hair, in particular, how quickly the hormones enter the hair after circulation in the blood and what time interval (weeks to months) is indicative of bioaccumulation of the hormones in the sample. In this regard, the results obtained from different animal species are somewhat contradictory. Accordingly, for each group of animals it is important to determine what information can be obtained by measuring the level of steroid hormones in the hair.
Scientists from the A.N. Severtsov Institute of Ecology and Evolution RAS assessed the possibility of using feline hair to measure seasonal changes in cortisol and testosterone levels in four species with different breeding strategies (seasonal and non-seasonal).
Hair testosterone concentrations in four feline species coincided with their reproductive cycle: increased during the mating season in seasonal species, remained high in non-seasonal caracals. Males were found to have higher testosterone concentrations than females. Hair cortisol levels also showed a significant pattern: changes in housing conditions (smaller cells) led to an increase in cortisol levels; the mating period and disturbance of the animals were also associated with an increase in cortisol levels. Measurement of these two hormones in feline hair samples can be a reliable tool for monitoring hormonal changes in captive and wild individuals.
This work was supported by the Russian Science Foundation grant 18-14-00200.
Naidenko, S. V., Alekseeva, G. S., Klyuchnikova, P. S., & Erofeeva, M. N. (2022). Application of Felid Hair for Non-Invasive Tracking of Animal Reproductive Status and Adrenal Activity. Animals, 12(20), 2792. https://doi.org/10.3390/ani12202792