Received: 9 May 2017 | Revised: 25 September 2017 | Accepted: 26 September 2017 DOI: 10.1002/ajp.22714 RESEARCH ARTICLE Thyroid hormone fluctuations indicate a thermoregulatory function in both a tropical (Alouatta palliata) and seasonally cold-habitat (Macaca fuscata) primate Cynthia L. Thompson1 | Brianna L. Powell2 | Susan H. Williams3 | Goro Hanya4 | Kenneth E. Glander5 | Christopher J. Vinyard6 1 Department of Biomedical Sciences, Grand Valley State University, Allendale, Michigan 2 Department of Biology, Grand Valley State University, Allendale, Michigan 3 Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine, Athens, Ohio 4 Ecology & Conservation Section, Department of Ecology & Social Behavior, Primate Research Institute, Kyoto University, Inuyama, Japan 5 Department of Evolutionary Anthropology, Duke University, Durham, North Carolina 6 Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio Correspondence Thyroid hormones boost animals’ basal metabolic rate and represent an important Cynthia L. Thompson, Department of Biomedical Sciences, 220 Padnos Hall, Grand thermoregulatory pathway for mammals that face cold temperatures. Whereas the Valley State University, One Campus Drive, cold thermal pressures experienced by primates in seasonal habitats at high latitudes Allendale, MI 49401. Email:
[email protected] and elevations are often apparent, tropical habitats also display distinct wet and dry seasons with modest changes in thermal environment. We assessed seasonal and Funding information National Science Foundation, Grant number: temperature-related changes in thyroid hormone levels for two primate species in BCS-0720028/0720025; Conservation disparate thermal environments, tropical mantled howlers (Alouatta palliata), and International; GVSU's CSCE Interdisciplinary Research Initiative; GVSU's Office of seasonally cold-habitat Japanese macaques (Macaca fuscata).