Stress in wildlife: comparison of the stress response among domestic, captive, and free-ranging animals

Abstract

The stress response, which involves joint activity of the nervous and endocrine systems, is one of the basic adaptive mechanisms that ensures the survival of the individual. The activation of the sympathetic nervous system, the sympathetic-adrenal-medullary axis, and the hypothalamic–pituitary–adrenal axis enables organisms to respond to endogenous and exogenous challenges. Repeated short-term stress leads to long-term stress, which disrupts physiological homeostasis. Unlike domestic animals, wild animals are not protected from environmental and weather influences or treated for diseases. In addition, climate change, habitat fragmentation and loss, and urban stressors (such as light, noise and chemical pollution; xenobiotics; traffic; and buildings) affect individual wildlife and populations. In this review, we have attempted to depict the magnitude of the stress response in wildlife and related domestic animals as well as in captive and free-ranging animals. The intensity of the stress response can be estimated by determining the concentration of glucocorticoids in body fluids, tissues, and excreta. A comparison of results from different studies suggests that domestic animals have lower fecal and hair glucocorticoid concentrations than related wild animals. Additionally, fecal and hair glucocorticoid concentrations in captive animals are higher than in free-ranging animals of the same species. As there are limited data on this topic, we cannot draw definitive conclusions about glucocorticoid concentration and stress response. Further studies are needed to clarify these issues.

Use of Infrared Thermography and Heart Rate Variability to Evaluate Autonomic Activity in Domestic Animals

“…The stress response is mediated by the ANS and the balance between the SNS and PNS [1]. Immediately after the perception of a stressor or a stimulus that threatens the animal's homeostasis [4,17,18], several physiological, endocrine, and metabolic changes are triggered to restore homeostasis. The SNS modulates the activity of the cardiovascular, gastrointestinal, respiratory, renal, and endocrine systems, among others [19].…”

“…The coordination of the central and peripheral responses to a stressor involves the hypothalamic-pituitary-adrenal (HPA) and the sympathetic-adrenomedular (SAM) axes [3]. These systems activate physiological, endocrine, and metabolic adaptive mechanisms to ensure the animal's survival [4]. Among these changes, modifications in the skin's sympathetic blood flow can occur due to physical, mental, and thermal stress [5][6][7], which can be non-invasively evaluated through infrared thermography (IRT) [8,9].…”

Is membrane androgen and estrogen receptor signaling imperative in the governing function of the adrenal cortex in the Eurasian beaver (Castor fiber L.)?

“…The wildlife population is affected by environmental stress, food deprivation, parasite infestation, and numerous untreated diseases which is not the case in domestic animals. Furthermore, human-wildlife management interventions, climate change, poaching, and invasive species are also negative stressors to wildlife (Karaer et al, 2023). Stress disturbs the growth, development, reproduction, and survival of organisms thus finally affecting wildlife population dynamics (Pirotta et al, 2018).…”

Comparison of infrared thermography of the blowhole mucosa with rectal temperatures in killer whales (Orcinus orca)

“…Non-invasive techniques can reduce stress due to handling by minimizing or preventing physiological responses resulting from functional changes in the hypothalamus-pituitaryadrenal axis and the sympathetic-adrenal-medullary axis. Activation of these systems during handling of cetaceans can potentially result in stress-induced hyperthermia, electrolyte derangements, and changes in circulating thyroid hormones (Hao et al, 2009;Karaer et al, 2023). In addition, non-invasive methods avoid the potentially serious complications associated with the use of sedatives for chemical restraint (Dold and Ridgway, 2014).…”