The effect of randomly altering the time and location of feeding on the behaviour of captive coyotes (Canis latrans)

Captive carnivores appear highly susceptible to the negative effects of predictable feeding routines. Current research and reviews suggest feeding unpredictably may increase species typical behaviour, but positive results have been limited to a few species. Our objectives were to determine whether randomly altering the time and location of feeding increased species typical behaviour, or affected the temporal distribution of captive coyote (Canis latrans) behaviour. We assigned 12 coyotes individually to either a predictable or an unpredictable (in time and location) feeding condition and measured behaviours in the morning and evening. Overall, mean time spent foraging, travelling, resting or standing was similar in both conditions, but coyotes in the unpredictable condition marked (118 vs. 42; P = 0.01, one-tailed) and howled (81 vs. 24; P = 0.05, one-tailed) significantly more than coyotes in the predictable condition. There were also significant temporal differences (a.m. vs. p.m.) in behaviour between conditions. Specifically, coyotes fed predictably foraged (P = 0.03) and travelled (P = 0.03) more in the morning and rested (P = 0.03) more in the evening, whereas coyotes fed unpredictably howled (62 vs. 19; P = 0.03) and stood (P = 0.05) more in the morning and foraged (P = 0.03) more in the evening. Optimum predictability for captive carnivores should be based on species-specific captive study results and relevant ecological data. Our results suggest coyote feeding regimes may be improved by including unpredictable elements nested within a predictable framework to mirror seasonal fluctuations in resources and increase species-specific behaviour in captivity.     

Chemical scent constituents in feces of wild Iberian wolves (Canis lupus signatus)

In spite of the importance of feces in scent marking and intraspecific chemical communication of many mammals, only a few studies have examined the chemical constituents of feces that could have a signaling function. We described here the chemicals found in feces recently deposited in the wild by adult and pup Iberian wolves (Canis lupus signatus). By means of analyses using gas chromatography–mass spectrometry (GC–MS), we identified 77 compounds in feces of adult wolves, mainly heterocyclic aromatic organic compounds, such as indole or phenol, but also steroids, such as cholesterol, carboxylic acids and their esters between n-C₃ and n-C₁₈, aldehydes, alcohols and significant quantities of squalene and α-tocopherol, which would increase the chemical stability of feces on humid substrates. Some of the odoriferous compounds are very likely originated in the anal-sac secretions, and later incorporated onto feces during defecation. However, the abundance of the main odoriferous compounds in feces could be explained by the result of the bacterial action on food components. Feces of pups only had 26 compounds, most of these were also found in adults’ feces, but four compounds were only found in pups’ feces, and there were also age-related differences respect to the proportions of shared chemicals. These differences could be partly due to the absence of anal-sac glands in pups, which would not need to scent mark substrates.     

Influence of exogenous gonadotropin-releasing hormone on seasonal reproductive behavior of the coyote (Canis latrans)

Wild Canis species such as the coyote (C. latrans) express a suite of reproductive traits unusual among mammals, including perennial pair-bonds and paternal care of the young. Coyotes also are monestrous, and both sexes are fertile only in winter; thus, they depend upon social and physiologic synchrony for successful reproduction. To investigate the mutability of seasonal reproduction in coyotes, we attempted to evoke an out-of-season estrus in October using one of two short-acting gonadotropin-releasing hormone (GnRH) agents: (1) a GnRH analogue, deslorelin (6-d-tryptophan-9-(N-ethyl-l-prolinamide)-10-deglycinamide), 2.1 mg pellet sc; or (2) gonadorelin, a GnRH (5-oxoPro-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-GlyNH₂) porcine hypothalamic extract, 2.0 μg/kg im once daily for 3 consecutive days. A transient increase in serum concentrations of estradiol and progesterone (1 and 2 wk, respectively) was detected after treatment with deslorelin but not gonadorelin. Also, socio-sexual behaviors reminiscent of winter mating (including courtship, mate-guarding, precoital mounts, and copulatory ties) were observed among the deslorelin group. During the subsequent breeding season (January and February), however, preovulatory courtship behavior and olfactory sampling appeared suppressed; emergence of mounts and copulations were delayed in both deslorelin and gonadorelin treatment groups. Furthermore, whereas 8 of 12 females treated in October ovulated and produced healthy litters in the spring, 4 naïve coyotes failed to copulate or become pregnant. Thus, perturbation of hormones prior to ovulation in species with complex mating behaviors may disrupt critical intrapair relationships, even if fertility is not impaired physiologically.