Integrity of mating behaviors and seasonal reproduction in coyotes (Canis latrans) following treatment with estradiol benzoate

Abstract

Coyotes (Canis latrans) are seasonally monestrous and form perennial pair-bonds. Breeding is dominated by each pack's alpha male and female, and both sexes share responsibility for territory defense and pup-rearing. They are also opportunistic predators on domestic livestock and pets. But while dominant adults have been implicated as primary killers, depredation is reduced when coyotes are without pups. Contraception, therefore, may represent a non-lethal solution for conflicts between coyotes and humans. Steroid hormones successfully control fertility in some species, but have been considered contraindicated in wildlife and canids in particular; specific concerns include possible induction of aberrant behavior, or uterine and hematopoietic pathologies. Herein we describe a study examining the physiological effectiveness, health safety, and behavioral consequences following treatment of estrous coyotes with exogenous estrogen. We treated captive adult female coyotes in estrus with 0.01mg/kg estradiol benzoate (EB), either before (n=5) or immediately after ovulation (n=6), then documented reproductive outcome, physiological variables and behavioral responses, during and after treatment. Pregnancy was averted in six females treated after ovulation, suggesting that appropriate timing of treatment proved crucial. A transient suppression of sexual behavior was observed, and in some cases, estrus appeared slightly lengthened. However, neither ovulation nor mating behavior was fully suppressed. Importantly, non-pregnant females (and their mates) displayed diestrous socio-sexual behavior similar to pregnant coyotes (behavioral pseudopregnancy). Furthermore, non-pregnant coyotes did not mate again until the next native breeding season, and we observed no deleterious physiological effects during diestrus or subsequent ovarian cycles.

Mating System of Free-Ranging Dogs (Canis familiaris)

“…In contrast, the results of this and other studies suggest that the free-ranging domestic dogs of West Bengal breed once a year [17,[27][28][29]. Single mating season was also reported by [30][31][32][33][34] in case of coyotes (Canis latrans). Domestic dogs (Canis familiaris) are considered nonseasonal breeders with the exception of the Basenji which shows an annual seasonal period of estrus during the fall [35].…”

Olfactory attractants and parity affect prenatal androgens and territoriality of coyote breeding pairs

“…The observed hormonal patterns are in accord with previous findings on female progesterone [61] and male testosterone [64,100] in coyotes, and may be explained by several factors. First, glucocorticoids and androgens peak early during the breeding season, which corresponds with a peak in scent-marking behaviors of previous studies [63,72,101]. It is likely that hormonal physiology accompanies the onset and regression of marking behaviors, similar to urine-marking and testosterone in gray wolves [28].…”

“…Coyotes (Canis latrans) are an excellent organism to examine the impact of environmental and temporal variation on gestational hormones and behavior. First, previous work has demonstrated increased serum testosterone and progesterone profiles over the mating season (December to February) that correspond with increased territorial behaviors such as urine-marking, ground scratching, and defecation [61][62][63][64]. Second, mated individuals frequently demarcate the boundaries of their territories via scent-marking and enforce home range limits using aggression against intruding conspecifics when necessary [65][66][67].…”