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Adult male Atlantic walruses (Odobenus rosmarus rosmarus) vocalize extensively underwater during the breeding season. The individual calls are composed of one or more short repetitious pulses which may vary individually in the number, pattern, and rate at which they are given. Individual male walruses give repeated stereotyped vocalization cycles totalling several hundred pulses each for up to several hours at a time, both while the whole body is submerged and between breaths with the head submerged while at the surface. We analyzed the vocalization cycles of a sample of different walruses, and sound spectrograms of particular calls from within those cycles, to test the hypothesis that the stereotyped vocalizations of individuals are unique and recognizable. In our sample, the pulse patterns of particular calls given by individual walruses in a series of vocalization cycles were nearly identical but were consistently different from the same call given by other animals. One call, the diving vocalization of a recognizable male, was identical in two different years.

We quantify the first complete description of breeding behavior and activity budgets of an undisturbed pair of adult polar bears, observed 24 h/d for 13 d from 2 to 15 May 1997, at Radstock Bay, Devon Island, Nunavut, Canada. The male herded the female to an area of 1–2 km2, where we observed them throughout the observation period. All behaviors were documented from when the adult female and her 2.5‐yr‐old cub were first observed being followed by an adult male, through separation of the cub from its mother, a week of intense interactions preceding several days with copulation, after which they parted. They mated for 51, 86, 66, and 150 min on 9–10, 12, 13, and 14 May, respectively, and parted on 14–15 May. The male deterred three challengers. The peak breeding season for polar bears runs from early April through mid‐May, although additional mating behavior has been documented in June. Timing of mating and duration of copulations in the wild were similar to reports from zoos. Induced ovulation, male intrasexual competition, female fitness, the mating system, and potential consequences of climate warming are discussed with insights made possible by documentation of the reproductive behavior of wild polar bears.

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