Influence of possible stressors on the respiration of three female Pacific Walruses (Odobenus rosmarus divergens), housed in managed care

In the present study we evaluated how feeding, enrichment, and presence of public affected breathing frequency (fR) in three females of Pacific walruses (Odobenus rosmarus divergens) housed in managed care at the Avanqua Oceanogràfic Ágora in Valencia, Spain. The fR was measured as the walruses were breathing spontaneously in the pool and only when they were actively swimming. The average body mass (Mb) and fR for the three animals were: 906 ± 28 kg / 3.7 ± 1.6 breaths * min-1; 787 ± 11 kg / 3.0 ± 2.2 breaths * min-1; 665 ± 9 kg / 4.3 ± 1.4 breaths * min-1, respectively. We compared if fR varied with number of guests in the habitat (low/medium/high), feeding state (pre-feed/non-feed/post-feed), time of the day, the presence of environmental enrichment and Mb. Only feeding state affected fR and the best model that explained the data was: fR = 3.55 + 0.46 * after feeding, showing that fR increased by 13% after feeding. For mass-corrected fR (sfR) the equation was: fR/Mb = 0.0047 + 0.00059 * after feeding. These data provide clues that supports that feeding alters physiology in walruses, possible due to increased metabolic rate caused by digestion.