Skin temperature and reproductive condition in wild female chimpanzees

Abstract

Infrared thermal imaging has emerged as a valuable tool in veterinary medicine, in particular for evaluating reproductive processes. Here, we explored differences in skin temperature of twenty female chimpanzees in Budongo Forest, Uganda, four of which were pregnant during data collection. Based on previous literature in other mammals, we predicted increased skin temperature of maximally swollen reproductive organs of non-pregnant females when approaching peak fertility. For pregnant females, we made the same prediction because it has been argued that female chimpanzees have evolved mechanisms to conceal pregnancy, including swellings of the reproductive organs, conspicuous copulation calling, and solicitation of male mating behaviour, to decrease the infanticidal tendencies of resident males by confusing paternity. For non-pregnant females, we found slight temperature increases towards the end of the swelling cycles but no significant change between the fertile and non-fertile phases. Despite their different reproductive state, pregnant females had very similar skin temperature patterns compared to non-pregnant females, suggesting little potential for males to use skin temperature to recognise pregnancies, especially during maximal swelling, when ovulation is most likely to occur in non-pregnant females. We discuss this pattern in light of the concealment hypothesis, i.e., that female chimpanzees have evolved physiological means to conceal their reproductive state during pregnancy.

Refinement of Methodology for Better Estimation of Pregnancy Diagnosis in Macaca fascicularis by DeepComputational Analysis of The Thermal Images

“…The preliminary results indicate the potential of thermal imaging in late-pregnancy diagnosis. Physiologically, the more progressing days of pregnancy correlate with an increase of the amount of vascularization and tissues' formation and all of these will bring consequences to potential increase of temperature (Dezecache et al, 2017). Our findings support the above physiological entity.…”

“…Promoting non-invasive methods in research and routine husbandry procedure are one of the best practices (NC3Rs 2018). Providing non-invasive measurements to measure physiological values to conventional clinical examination that require chemical restrains, are also considered as refinement (Dezecache et al, 2017;Hau and Schapiro, 2004). The thermal imaging may be one of the non-invasive criteria which provide a real-time measurement of the basic physiological value of body temperature thus useful to estimate the health status (Cilulko and Janiszewski, 2013;Christiansen et al, 2014).…”

“…The thermal imaging may be one of the non-invasive criteria which provide a real-time measurement of the basic physiological value of body temperature thus useful to estimate the health status (Cilulko and Janiszewski, 2013;Christiansen et al, 2014). The importance of the thermal imaging becomes greater for wildlife animal use and/or certain animals that in necessity to be sedated in health examination (Dezecache et al, 2017). Thermal camera had been used for basic examination to body temperature (Christiansen et al 2014), and with better algorithm and computerized interpretation to the thermal images, we may potentially gain more benefit.…”

Thermal imaging reveals audience-dependent effects during cooperation and competition in wild chimpanzees

“…Thermal imaging has previously been calibrated with standard methods of measuring physiological activity, such as heart rate (electrocardiography), respiration (piezoelectric thorax stripes), skin conductance (galvanic skin response) or skin temperature (nasal thermistors) 24 . Furthermore, in wild chimpanzees the method has been used in two pilot studies investigating responses to vocalisations 26 and differences in females’ reproductive states 27 .…”

An Evaluation of Two Low-Cost Thermal Imaging Cameras for Wildlife Damage Management Objectives

“…Most wildlife application of thermal imaging are based upon locating and identifying animals in darkness (Bipad-Cilulko et al 2013). Utilization of the technology in stress and behavioral studies have been reported in songbirds , waterfowl (Austin et al 2016), flying squirrels (Horton et al 2015) and various primates (Kano et al 2015, Ioannou et al 2015, Dezecache et al 2017.…”