title: Annual testosterone rhythm in the black bear (Ursus americanus).
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002335:Carnivora; D002940:Circadian Rhythm; D004781:Environmental Exposure; D008297:Male; D012098:Reproduction; D012621:Seasons; D013737:Testis / Q000033:anatomy & histology; D013739:Testosterone / Q000097:blood*; D013997:Time Factors; D001503:Ursidae
chemical_list: D013739:Testosterone