More Like this

1. Body temperature estimates for Bornean orangutans (Pongo pygmaeus wurmbii) from internal fecal temperature measurements

   Harwell, Faye S; Scott, Katherine S; Philp, B; Knott, Cheryl D (March 2019, American journal of physical anthropology)

   Monitoring health status is a critical aspect of primate conservation, yet can be difficult to noninvasively investigate in the wild. Because mammals are endothermic, body temperature can be used as a health marker for primates. Using a method previously tested on chimpanzees and humans, we estimated body temperature of wild Bornean orangutans by measuring the internal temperature of fecal samples. Upon quickly collecting a fecal sample after defecation, we recorded internal temperature of the sample at 20-sec intervals for six minutes. Data included a series of temperatures for each sample that we fitted to a sigmoid curve, which was used to estimate body temperature. Estimated body temperature was not affected by sex (F(2,92)= 0.431, P= 0.651), weather (F(2,92)= 1.175, P= 0.313), or collection time (r= -0.074, N= 95, P= 0.468). Estimated body temperature was higher for fecal samples that fell from lower estimated heights (r= -0.23, N= 95, P= 0.0004) and were heavier (r= 0.23, N= 75, P= 0.0475). We compare these results from the field to captive fecal samples, taking place on the ground, to determine the accuracy of this field method. From our field samples (N=95), orangutans appear to have a lower internal body temperature (33.44 ± 1.74 °C) on average than either chimpanzees or humans. Previous studies have demonstrated that orangutans have a lower metabolic rate than other great apes. Lower body temperature may serve as a metabolic adaptation of orangutans to survive extended periods of low food availability when energy needs to be conserved. 

   more » « less
2. Estimation of body temperature of Bornean orangutans (Pongo pygmaeus wurmbii) from fecal temperature measurements

   Harwell, Faye S; Gotama, Rinaldi; Syainullah, Muhammad; Junardi, Junardi; Mitra Setia, Tatang; Philp, Brodie; Knott, Cheryl D. (November 2019, Fifth Annual Meeting of the Northeastern Evolutionary Primatologists)

   Monitoring health status is a critical aspect of primate conservation, yet can be difficult to noninvasively investigate in the wild. Internal body temperature, a marker of health in endotherms, has been tested in humans and chimpanzees using two different fecal temperature methods: using the peak internal temperature (PIT) or applying a sigmoid curve (SC). We tested both methods on wild and rehabilitant Bornean orangutans to determine if either is a feasible methodology for arboreal mammals. The SC method involves a series of temperatures for each sample that we fitted to a sigmoid curve, whereas the PIT method involved a single peak temperature recording. Estimates from the two methods were not significantly different in either our wild (T(88)= -2.0781, P=0.0406) or rehabilitant (T(29)= -2.8404, P=0.0082) samples. Adult rehabilitant body temperatures (N=9; 34.62 ± 1.32°C) were estimated to be hotter than those in the wild (N=107; 33.59 ± 1.66°C), although not significantly different (T(115)=1.9859; P=0.0493). In our model, testing a number of factors, we found height of fecal drop (P=0.0071), fecal weight (P=0.0198), and time of day (P=0.0029) to significantly affect body temperature estimates. Our field sample (N=107) indicates that wild orangutans have an internal fecal temperature, ranging between 29.5 and 37.3°C, lower than mean temperatures for chimpanzees or humans. This supports the finding that orangutans have lower metabolic rates than do most other eutherian mammals. Lower body temperature may serve as a metabolic adaptation of orangutans to survive extended periods of low food availability when energy needs to be conserved. 

   more » « less
3. A comparison of specific gravity and creatinine for determining urine concentrations in captive orangutans for monitoring health status and physiology

   Malbouf, Bryanna B.; Kane, Erin E.; Durgavich, Lara S.; Knott, Cheryl D (February 2020, American journal of physical anthropology)

   Biomarkers including reproductive hormones and indicators of energy balance can be used to analyze health status and physiology in wild animals. Non-invasive collection of urine or feces enables biomarker monitoring, important for critically endangered species like orangutans. Hormonal measurements must control for urine concentration, typically done using creatinine or specific gravity. Specific gravity measurement compares the density of urine with the density of water. Creatinine is a breakdown product of muscle metabolism that is excreted from the body at a relatively stable rate, and it is an indicator of relative muscle mass in many species. Here, we measure specific gravity in urine samples from captive female orangutans using a digital hand-held urine specific gravity refractometer. We compare specific gravity to previously measured creatinine values and assess the influence of time of collection and refractometer temperature on specific gravity. We found a significant positive correlation between specific gravity and creatinine concentrations (N=1021, Pearson’s R=0.578, p<0.001). While we found no significant correlation between the time that samples were collected and specific gravity readings (N= 314, Pearson’s R=0.079, p=0.17), readings from morning samples were slightly but significantly lower (N=255, mean=1.008) than afternoon samples (N=60, mean=1.009) (independent samples t-test, t312=-1.969, p=0.05). We found a significant negative correlation between specific gravity and refractometer temperature (Pearson’s R=-0.23, p<0.001), highlighting the need to control for urine temperature when using thawed samples. 

   more » « less
4. A comparison of great ape life histories in captivity

   Harwell, Faye; Knott, Cheryl D. (November 2020, 6th Annual Meeting of the Northeastern Evolutionary Primatologists)

   null (Ed.)

   Primates, especially great apes, have slow life histories and long lifespans compared to other mammalian groups. Data pertaining to life history variables can be difficult to collect in the wild considering that species can have longer lifespans than the duration of a field site’s existence. Here, we examine life history variables for captive-born great apes housed in the United States. Using studbook data, we investigate stillbirth rates, age at first birth (AFB), interbirth intervals, number of offspring, twinning rates, mean lifespan and maximum lifespans. Analyses presented here exclude individuals with estimated birthdates. The oldest maximum lifespan was recorded for gorillas (60.07yrs (female); n= 656) followed by chimpanzees (57.40yrs (female); n= 559), orangutans (54.88yrs (female); n= 660), and bonobos (52.15yrs (female); n= 144). Excluding individuals living ≤10 years of age, mean lifespan is similar for all great apes in captivity (F(3,417)= 0.849, p= 0.467; bonobos: 23.5 ± 9.8yrs; chimpanzees: 25.2 ± 10.6yrs; gorillas: 26.2 ± 10.2yrs; orangutans: 24.2 ± 10.0yrs). The stillbirth rate is highest in chimpanzees (0.147; n=559) then gorillas (0.144; n=658), bonobos (0.125; n=144), and orangutans (0.010; n=681). Gorillas (11.4 ± 3.7yrs) have a younger AFB, on average, than chimpanzees (15.9 ± 6.9yrs), bonobos (14.3 ± 6.9yrs), or orangutans (14.4 ± 5.1yrs) (F(3,377)= 13.97, p< 0.0001). We discuss how our findings are influenced by changes in husbandry practices as well as the captive environment. By examining the life histories of captive populations, we highlight the plasticity these species exhibit in relation to the timing of developmental and reproductive events. 

   more » « less
5. Noninvasively Monitoring Orangutan Health Status: Determining Urine Concentrations

   Malbouf, Bryanna; Kane, Erin E; L Durgavich, Lara; Knott, Cheryl D (November 2019, Fifth Annual Meeting of the Northeastern Evolutionary Primatologists)

   Biomarkers including reproductive hormones and indicators of energy balance can be used to analyze health status in wild animals. Non-invasive measures, analyzed through urine or feces, enable biomarker monitoring without interfering with organisms, important for critically endangered species like orangutans. A measure of urine concentration such as creatinine concentrations or specific gravity is necessary when analyzing urine samples. Here, we measure specific gravity in urine samples from three captive female orangutans using a digital hand-held urine specific gravity refractometer. We compare specific gravity to previously measured creatinine values for two orangutans, and assess the influence of time of collection and refractometer temperature on specific gravity for all three. We found a significant positive correlation between specific gravity and creatinine concentrations (N=1021, Pearson’s R=0.578, p<0.001). While we found no significant correlation between the time that samples were collected and specific gravity readings (N= 314, Pearson’s R = 0.079, p=0.17), readings from samples collected in the morning were slightly but significantly lower (N=255, mean=1.008) than samples collected in the afternoon (N=60, mean=1.009) (independent samples t-test, t312=-1.969, p=0.05). We found a significant negative correlation between specific gravity and the refractometer temperature (Pearson’s R=-0.23, p<0.001). In future studies, specific gravity can be used to determine urine concentration rather than creatinine, which is more costly and requires more time for lab work. Our future research will examine the correlation between specific gravity and creatinine concentrations as orangutans age, and the effects of aging on muscle wasting and reproductive status. 

   more » « less