| Although conservational actions have been taking for protecting wildlife,their health may be impaired due to chronic stress and energy deficit caused by food scarcity,habitat fragmentation,and anthropogenic disturbances.Thus,monitoring the health of animals is vital for wildlife conservation.However,it is difficult to obtain blood samples from endangered wildlife,and blood collection may injure animals and introduce measurement bias.Non-invasively collected samples,i.e.,feces,urine and hair etc,can provide valuable information about the physiological and biochemical status,and minimize damage to animals,so they are increasingly applied in wildlife research and conservation.Metabolites in non-invasive samples would be used as direct monitor indictor for the health state or the strategies of energy expenditure.For example,metabolites of cortisol(COR),the main glucocorticoid secreted in primates,is elevated in stress response,which may adversely affect animal health.It is well known that thyroid hormone(T3m)plays a key role in the basal metabolic rate,as well as in the regulation of body metabolism.The golden snub-nosed monkey(Rhinopithecus roxellana)is a national first-class protected animal and endemic to China,and thus makes monitor their health is especially important.In this paper,non-invasive samples were applied to monitor captive,provision but free,and wild golden snub-nosed monkeys’physiological status with COR and T3m as indicators.Firstly,biological analytical validations were conducted for COR and T3m assays.Secondly,the potential correlations between the intensity of tourism activity and urinary COR levels were investigated.Thirdly,the biological relevance between fecal T3m concentrations and ambient temperature was examined.Finally,variations of T3m levels related to the female reproductive state were determined.The main findings are as follows:1.Urinary and fecal COR concentrations increased following stress manipulation.The time lag was 3.5 h in urine,and around 23 h in feces.2.Tourism could lead to elevation of cortisol secretion in habituated golden snubnosed monkeys.Different aspects of tourism affect the monkeys in different ways.COR level was not associated with the number of tourists,but raised as exposure time to tourists increased.And the proximity of tourists could trigger COR secretion in golden snub-nosed monkeys.3.In winter,when experiencing reductions in ambient temperature,the fecal T3m concentration is elevated in provisioned monkeys;the wild-feeding group of golden snub-nosed monkeys ranging at higher altitudes has higher fecal T3m levels compared to the provisioned group at lower altitudes during the same period.The reduction in ambient temperature also made the wild-feeding group descend to lower altitudes.With the descent of altitudes,the levels of fecal T3m were significantly reduced in the wildfeeding group as well.These results indicated that golden snub-nosed monkeys secreted more T3 to maintain body temperature in the face of thermal stress;the reduced T3m concentration after descending to lower altitudes might be caused by declined food availability which results in the monkeys suffering nutritional stress.All in all,this study draws a picture of a primate with a highly flexible energetic physiology,which arguably is a necessary characteristic of populations inhabiting such extreme seasonal environments.Contrary to previous suggestions,the present study also indicates that thermal stress is significantly higher at higher altitudes,bringing direct physiological support for the idea that food distribution is the driving force behind the high altitudinal ranging patterns in these primates in winter.4.T3m concentrations didn’t vary with reproductive state among female snubnosed monkeys in summer and autumn.Late-lactating females had higher T3m levels than early-lactating females in spring.T3m levels were lower in late-lactating females compared to pregnant females in winter,reflecting nursing offspring was more costly than gestation during this period.The thermoregulation stress and energy expenditure of lactating in winter may result in the two years interbirth interval of golden snubnosed monkeys.This study shows that tourism could lead to elevation of COR secretion in golden snub-nosed monkeys even if they were long-term habituated.Tourists visiting time and distance to the golden snub-nosed monkeys need to be limited to minimize the potentially detrimental effects of tourism.Fecal T3m levels elevated in response to reduction of ambient temperature,indicating increased basal metabolic rate in golden snub-nosed monkeys.In winter,nursing females had lower fecal T3m levels than pregnant females,exhibiting energy sparing metabolic strategy.The energetic stress of lactation and thermoregulation may lead to the two-year interbirth interval in golden snub-nosed monkeys. |
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