Evidence from urinary cortisol that maternal behavior is related to stress in gorillas1 11The collection of behavioral data and urine samples from the gorillas at Zoo Zürich was approved by the Kantonales Veterinäramt Zürich, Switzerland
1998; Elsevier BV; Volume: 64; Issue: 4 Linguagem: Inglês
10.1016/s0031-9384(98)00057-2
ISSN1873-507X
AutoresNina I. Bahr, Christopher R. Pryce, M. Döbeli, Robert D. Martín,
Tópico(s)Stress Responses and Cortisol
ResumoBAHR, N.I., C. R. P. PRYCE, M. DÖBELI AND R.D. MARTIN. Evidence from urinary cortisol that maternal behavior is related to stress in gorillas. PHYSIOL BEHAV 64(4) 429–437, 1998.—By studying western lowland gorillas (Gorilla gorilla gorilla, n = 8) in zoological gardens via ethological and non-invasive physiological techniques, we have demonstrated that their postpartum maternal behavior is related negatively to their postpartum urinary titers of cortisol. On the basis of this finding, it is proposed that postpartum stress contributes to disrupted maternal behavior in the gorilla in captivity. Morning urine samples were collected with a mean sampling interval of 1.6 days from Day 14 prepartum to Day 14 postpartum (n = 11 pregnancies). Creatinine-indexed (Cr) urinary cortisol titers declined significantly between Day 9 to 1 prepartum (0.634 ± 0.014 μg/mg of Cr, mean ± SEM) and Day 1 to 6 postpartum (0.396 ± 0.030 μg/mg of Cr, mean ± SEM; p < 0.01–0.001). For each pregnancy, the relative postpartum decline in urinary cortisol was calculated as (μg of cortisol/mg of Cr Day 1 to 4)/(μg of cortisol/mg of Cr Day −4 to -1). Values ranged from 0.35 to 1.12, were independent of absolute prepartum cortisol titers, and were interpreted as evidence of inter-female differences in postpartum hypothalamo–pituitary–adrenal axis activity and, therefore, postpartum stress. This postpartum stress index was negatively correlated with the amount of time (0–100%) that females carried and supported their 0–14 day-old infants in a ventral position during locomotion (rs = −0.68, p < 0.05) and tended to be negatively correlated with the total amount of time (0–100%) they spent in ventro–ventral contact with their infants (rs = −0.58; p < 0.10). This study provides the first physiological evidence that postpartum stress is an important etiologic factor in gorilla maternal failure in captive environments.
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