Breathing and heart rates of the southern elephant seal, Mirounga leonina (L.)

Observations were made on resting southern elephant seals, Mirounga leonina (L.), on the beach. The breathing pattern of pups is typically regular with rapid, shallow inhalations. With increasing age a rhythmic pattern of alternating apneic and eupneic phases is developed. Apneic periods of similar duration to previously recorded dives were observed from adult seals. The heart rate decreases with increasing age; rates recorded from cows increased at the cessation of lactation and the onset of the breeding season; at other times rates from adult males and females were similar. Body temperatures were higher at the onset of the winter sea-going period than at other times of the year. The histology of the lungs and thyroid glands is typically mammalian.