Applying Behavioral and Physiological Measures to Assess the Relative Impact of the Prolonged COVID-19 Pandemic Closure on Two Mammal Species at the Oregon Zoo: Cheetah (A. jubatus) and Giraffe (G. c. reticulata and G. c. tippelskirchii).

The effect of visitor presence on zoo animals has been explored in numerous studies over the past two decades. However, the opportunities for observations without visitors have been very limited at most institutions. In 2020, the Oregon Zoo was closed, in response to the global SARS-CoV-2 (COVID-19) pandemic, from 15 March 2020 to 12 July 2020, resulting in approximately four consecutive months without visitor presence. This study aimed to quantify potential behavioral and hormonal changes expressed during two transition periods in zoo visitor attendance: the initial time period before and after closure in March 2020 and time before and after reopening in July 2020. Fecal glucocorticoid metabolite (fGM) concentrations of resident giraffes (n = 2) and cheetahs (n = 2) were tracked using enzyme immunoassay (EIA) analyses. Average fGM concentrations during the two transition periods were compared using a two-way mixed ANOVA. Additionally, twice-weekly scan sampling was used to quantify behavioral observations across the transitions, which were analyzed as individual behavior proportions. Individual behavior proportions were compared across the Zoo's opening status and time of day using Kruskal-Wallis (H) tests. The results of our analyses showed the following outcomes: (1) significant increases in fGM concentrations for cheetahs and giraffes between the transition periods but not within them; (2) a significant increase in time spent 'not visible' in the cheetahs in the second transition period; and (3) increased vigilance behaviors in the giraffes immediately after the Zoo's closure. However, the changes observed in fGM concentrations may be more strongly correlated with concomitant social changes (giraffes) and some medical events (cheetahs) rather than with the Zoo's opening status. Nevertheless, this study was able to quantify differences in behavioral frequencies and fGM concentration in cheetahs and giraffes at the Oregon Zoo during the times of transition between visitor's presence and absence. The results indicate that, while there was a possible, but relatively minor impact of the presence and absence of visitors on some behaviors, the differences observed in fGM concentration may have been more affected by some of the concomitant social changes and medical events that happened during the same period than by the presence or absence of visitors.

Characterization of multiple pathways modulating aggression in the male clouded leopard (Neofelis nebulosa).

Breeding clouded leopards (Neofelis nebulosa) ex situ has been a challenge, primarily due to extreme and often fatal male aggression toward females. This study's aim was to determine the degree to which two possible mechanisms-serotonergic pathways and circulating testosterone levels-affect aggressive behavior. Male clouded leopard behavioral and hormonal data were collected during a series of behavior tests administered before and after treatment with either an anxiety-reducing tricyclic antidepressant (clomipramine) or a GnRH agonist (deslorelin). Results showed that clomipramine treatment decreased "overall activity" (P = 0.054) and increased "lying down" (P = 0.0043) and hiding in a "nest box" (P = 0.0023). Clomipramine treatment also decreased the incidence of "growling" during a mirror image stimulation test, relative to non-test periods (P < 0.0001 pre-drug treatment; P = 0.242 peri-drug treatment), indicating reduced aggression. Suppression of the reproductive axis via deslorelin treatment resulted in significant decreases in circulating androgen (P < 0.0001) and glucocorticoid (P < 0.0001), accompanied by decreased aggressive behaviors, including "swatting" (P = 0.0476), "tail flicking" (P = 0.0409), and "growling" during the behavior reaction tests: mirror image stimulation (P < 0.0001 pre-drug treatment: P = 0.7098 peri-drug treatment) and unfamiliar people test (P < 0.0001 pre-drug treatment: P = 0.2666 peri-drug treatment) relative to non-test periods. Both drug treatments provide evidence that multiple mechanisms modulate aggressive behavior in the male clouded leopard, suggesting that serotonergic modulation coupled with circulating androgens may aid in the formation of successful breeding pairs. Zoo Biol. 35:474-486, 2016. © 2016 Wiley Periodicals, Inc.

Comparative patterns of adrenal activity in captive and wild Canada lynx (Lynx canadensis).

Stress and animal well-being are often assessed using concentrations of glucocorticoids (GCs), a product of the hypothalamic-pituitary-adrenal axis. However, GC concentrations can also be modulated by predictable events, such as changes in season or life history stage. Understanding normative patterns of adrenal activity is critical for making valid conclusions about changes in GC concentrations. In this study, we validated an assay for monitoring fecal glucocorticoid metabolites (FGM) in Canada lynx. We then used this technique to assess patterns of adrenal activity in Canada lynx across several contexts. Our results show that captive lynx have higher FGM concentrations than wild lynx, which may be related to differences in stress levels, metabolic rate, diet, or body condition. We also found that FGM concentrations are correlated with reproductive status in females, but not in males. For males, seasonal increases in FGM expression coincide with the onset of the breeding season, whereas in females, FGM increase toward the end of the breeding season. This information provides a valuable foundation for making inferences about normative versus stress-induced changes in adrenal activity in Canada lynx.

Patterns of testicular activity in captive and wild Canada lynx (Lynx canadensis).

Canada lynx are listed as a threatened species in the contiguous US. Understanding the reproductive characteristics (i.e., mating system, behavior, physiology) of a species is useful for ensuring effective in situ and ex situ management plans. The goal of this study was to describe patterns of androgen expression in both captive and wild male Canada lynx using fecal hormone metabolite analysis. Among captive lynx, juvenile and castrated males had lower concentrations of fecal androgens (fA) than intact males, thereby demonstrating that the assay detects biologically meaningful differences in testicular activity. We found that captive males in general had much higher fA levels than wild males. All males showed strong seasonal variation in fA concentrations, with significantly higher levels being expressed during the breeding season (February and March) than during the non-breeding season. Among captive males, variation in seasonal fA levels did not correlate with latitude. Finally, males housed with intact cage-mates (either male or female) had significantly higher fA levels than males housed alone or with a neutered cage-mate.

Patterns of ovarian and luteal activity in captive and wild Canada lynx (Lynx canadensis).

Canada lynx face some unique breeding restrictions, which may have implications for population viability and captive management. The goal of this study was to improve our understanding of basic reproductive physiology in Canada lynx. Using fecal hormone metabolite analysis, we established normative patterns of fecal estrogen (fE) and progestagen (fP) expression in captive and wild female Canada lynx. Our results indicate that Canada lynx have persistent corpora lutea, which underlie their uncharacteristic fP profiles compared to other felids. Thus, fP are not useful for diagnosing pregnancy in Canada lynx. We also found that Canada lynx are capable of ovulating spontaneously. Captive females had higher concentrations of fE and fP than wild females. Both populations exhibit a seasonal increase in ovarian activity (as measured by fE) between February and April. Finally, there was evidence of ovarian suppression when females were housed together.