Abstract
State-dependent foraging theory posits that animals should make foraging decisions based on energetic condition, where animals with fewer energetic reserves prioritize foraging over other behaviors, including antipredator behaviors. However, few studies have investigated these trade-offs at an individual level in wild, free-ranging animals. We investigated the relationships between internal condition and behavior in a wild mammal, the vicuña (Vicugna vicugna), which makes state-dependent decisions about the use of two habitats with different characteristics that contribute to their internal condition. Using non-invasively collected fecal samples, we measured glucocorticoid metabolites (GCMs) and thyroid hormones (THs) as indicators of combined stress (predation and nutritional), and just nutritional stress, respectively. We video recorded 20-minute behavioral observations and focused on behaviors which often demand a trade-off between energy acquisition and antipredator behaviors—vigilance and foraging. We found differences in expression of these behaviors between the two sites but found no relationships between physiological parameters (GCMs and THs) and behavior (vigilance and foraging) at either site. We suggest that state-dependent foraging may be difficult to observe in large mammals under baseline conditions and that GCMs and THs may be insensitive to small changes in stress stimuli at this scale, and where these wild animals have the entire suite of behavioral responses available to them.
| Original language | English (US) |
|---|---|
| Article number | 113299 |
| Journal | General and Comparative Endocrinology |
| Volume | 286 |
| DOIs | |
| State | Published - Jan 15 2020 |
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All Science Journal Classification (ASJC) codes
- Animal Science and Zoology
- Endocrinology
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Glucocorticoid and triiodothyronine concentrations do not correlate with behavior in vicuñas (Vicugna vicugna). / Pritchard, Catharine E.; Palme, Rupert; Langkilde, Tracy.
In: General and Comparative Endocrinology, Vol. 286, 113299, 15.01.2020.Research output: Contribution to journal › Review article
TY - JOUR
T1 - Glucocorticoid and triiodothyronine concentrations do not correlate with behavior in vicuñas (Vicugna vicugna)
AU - Pritchard, Catharine E.
AU - Palme, Rupert
AU - Langkilde, Tracy
PY - 2020/1/15
Y1 - 2020/1/15
N2 - State-dependent foraging theory posits that animals should make foraging decisions based on energetic condition, where animals with fewer energetic reserves prioritize foraging over other behaviors, including antipredator behaviors. However, few studies have investigated these trade-offs at an individual level in wild, free-ranging animals. We investigated the relationships between internal condition and behavior in a wild mammal, the vicuña (Vicugna vicugna), which makes state-dependent decisions about the use of two habitats with different characteristics that contribute to their internal condition. Using non-invasively collected fecal samples, we measured glucocorticoid metabolites (GCMs) and thyroid hormones (THs) as indicators of combined stress (predation and nutritional), and just nutritional stress, respectively. We video recorded 20-minute behavioral observations and focused on behaviors which often demand a trade-off between energy acquisition and antipredator behaviors—vigilance and foraging. We found differences in expression of these behaviors between the two sites but found no relationships between physiological parameters (GCMs and THs) and behavior (vigilance and foraging) at either site. We suggest that state-dependent foraging may be difficult to observe in large mammals under baseline conditions and that GCMs and THs may be insensitive to small changes in stress stimuli at this scale, and where these wild animals have the entire suite of behavioral responses available to them.
AB - State-dependent foraging theory posits that animals should make foraging decisions based on energetic condition, where animals with fewer energetic reserves prioritize foraging over other behaviors, including antipredator behaviors. However, few studies have investigated these trade-offs at an individual level in wild, free-ranging animals. We investigated the relationships between internal condition and behavior in a wild mammal, the vicuña (Vicugna vicugna), which makes state-dependent decisions about the use of two habitats with different characteristics that contribute to their internal condition. Using non-invasively collected fecal samples, we measured glucocorticoid metabolites (GCMs) and thyroid hormones (THs) as indicators of combined stress (predation and nutritional), and just nutritional stress, respectively. We video recorded 20-minute behavioral observations and focused on behaviors which often demand a trade-off between energy acquisition and antipredator behaviors—vigilance and foraging. We found differences in expression of these behaviors between the two sites but found no relationships between physiological parameters (GCMs and THs) and behavior (vigilance and foraging) at either site. We suggest that state-dependent foraging may be difficult to observe in large mammals under baseline conditions and that GCMs and THs may be insensitive to small changes in stress stimuli at this scale, and where these wild animals have the entire suite of behavioral responses available to them.
UR - http://www.scopus.com/inward/record.url?scp=85073719550&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85073719550&partnerID=8YFLogxK
U2 - 10.1016/j.ygcen.2019.113299
DO - 10.1016/j.ygcen.2019.113299
M3 - Review article
C2 - 31606464
AN - SCOPUS:85073719550
VL - 286
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
SN - 0016-6480
M1 - 113299
ER -