Tracking of food quantity by coyotes (Canis latrans)

Previous studies have demonstrated that Weber's Law mediates quantitative discrimination abilities across various species. Here, we tested coyotes’ (Canis latrans) ability to discriminate between various quantities of food and investigated whether this ability conforms to predictions of Weber's Law. We demonstrate herein that coyotes are capable of reliably discriminating large versus small quantities of discrete food items. As predicted by Weber's Law, coyotes’ quantitative discrimination abilities are mediated by the ratio between the large and small quantities of food and exhibit scalar variability. Furthermore, in this task coyotes were not discriminating large versus small quantities based on olfactory cues alone.     

Experimental Babesia gibsoni infection in coyotes (Canis latrans)

Four 5 mo old captive raised coyotes (Canis latrans) were experimentally inoculated with approximately 1 x 10(6) Babesia gibsoni organisms. Parasites were detected 1 wk post-inoculation in all coyotes with maximum parasitemia of 8-11% occurring at 34 wk. Parasitemias remained at or above 1% for at least 12 wk and were still detectable 20 wk post-inoculation. All experimentally infected coyotes developed pale mucous membranes, splenomegaly, and a positive heme reaction in urine while one coyote exhibited mild depression and inappetence. Infected coyotes also developed a regenerative anemia, thrombocytopenia, and neutropenia. The mild clinical signs coupled with the high level and long duration of parasitemia indicate that coyotes could serve as reservoirs for B. gibsoni. Entrance of this foreign parasite into the United States suggests the need for strict quarantines and thorough health and blood film examinations for imported animals.     

Sensitivity of double centrifugation sugar fecal flotation for detecting intestinal helminths in coyotes (Canis latrans)

Fecal analysis is commonly used to estimate prevalence and intensity of intestinal helminths in wild carnivores, but few studies have assessed the reliability of fecal flotation compared to analysis of intestinal tracts. We investigated sensitivity of the double centrifugation sugar fecal flotation and kappa agreement between fecal flotation and postmortem examination of intestines for helminths of coyotes (Canis latrans). We analyzed 57 coyote carcasses that were collected between October 2010 and March 2011 in the metropolitan area of Calgary and Edmonton, Alberta, Canada. Before analyses, intestines and feces were frozen at -80 C for 72 hr to inactivate Echinococcus eggs, protecting operators from potential exposure. Five species of helminths were found by postmortem examination, including Toxascaris leonina, Uncinaria stenocephala, Ancylostoma caninum, Taenia sp., and Echinococcus multilocularis. Sensitivity of fecal flotation was high (0.84) for detection of T. leonina but low for Taenia sp. (0.27), E. multilocularis (0.46), and U. stenocephala (0.00). Good kappa agreement between techniques was observed only for T. leonina (0.64), for which we detected also a significant correlation between adult female parasite intensity and fecal egg counts (R(s)=0.53, P=0.01). Differences in sensitivity may be related to parasite characteristics that affect recovery of eggs on flotation. Fecal parasitologic analyses are highly applicable to study the disease ecology of urban carnivores, and they often provide important information on environmental contamination and potential of zoonotic risks. However, fecal-based parasitologic surveys should first assess the sensitivity of the techniques to understand their biases and limitations.     

Transmission of Ancylostoma caninum and Alaria marcianae in coyotes (Canis latrans)

One of seven female coyotes (Canis latrans) captured in Webb County, Texas during September 1986 and confined and mated in holding facilities at Millville, Utah whelped the following spring. The maternal female (greater than 5-yr-old) and her five neonates were killed at 22 days postparturition. All were infected with adult Ancylostoma caninum and were passing eggs in their feces. Also, the neonates and maternal female were infected with immature and adult Alaria marcianae, respectively. These findings suggested that the transmammary route is an important transmission mechanism for acquisition of these species of helminths in coyotes. The lack of overdispersion in the frequency distribution of these parasites and infection of the entire litter indicated that transmission from the infected female was nonselective among the pups.     

Helminth parasites of the coyote (Canis latrans) in Tennessee

From 1980 to 1984, 267 coyotes (Canis latrans) from Tennessee were examined for helminth parasites. Hearts were examined for the presence of Dirofilaria immitis, diaphragms for Trichinella spiralis, and digestive tracts for other helminths. Six species were found including 5 nematodes (D. immitis, Physaloptera rara, Trichuris vulpis, Ancylostoma caninum, and Toxascaris leonina) and 1 cestode (Taenia pisiformis). Univariate and multivariate statistical techniques were used to assess parasite prevalence and intensity. For prevalence data, a matrix of correlation among characters was computed, and the first 3 principal components were extracted from the original distance matrix. These accounted for 93.7% of the variation in the character set. Three-dimensional projections of localities showed spatial variability on each component. Significant relationships were found between principal component I and longitude, component II and latitude and mean January temperature, and component III and mean July precipitation and mean January actual evapotranspiration. For intensity data, no spatial variability was determined.     

Serologic survey for diseases in free-ranging coyotes (Canis latrans) from two ecologically distinct areas of Utah

The influence of habitat and associated prey assemblages on the prevalence of canine diseases in coyotes (Canis latrans) has received scant attention. From December 1997 through December 1999, we captured 67 coyotes in two ecologically distinct areas of Utah (USA): Deseret Land and Livestock Ranch and US Army Dugway Proving Ground. These areas differ in habitat and prey base. We collected blood samples and tested for evidence of various canine diseases. Prevalence of antibodies against canine parvovirus (CPV) was 100% in the Deseret population and 93% in the Dugway population. All juveniles in both populations had been exposed. We found no difference in the prevalence of antibodies against canine distemper virus (CDV) between the two populations (7% versus 12%; P = 0.50). However, we did find an increase in antibodies with age in the Deseret population (P = 0.03). Evidence of exposure to canine adenovirus (CAV) was found in both populations (52% and 72%; P = 0.08). Prevalence of CAV antibodies was influenced by age on both areas (Deseret: P = 0.003; Dugway: P = 0.004). Antibodies to Francisella tularensis were low on both areas (2% and 4%). We found a significant difference (P = 0.001) in the prevalence of exposure to Yersinia pestis between the two populations: 73% in Deseret compared to 11% in Dugway. This difference is most likely due to the prey species available in the two ecologically distinct study areas.     

Molecular systematics of Mesocestoides sPP (cestoda: mesocestoididae) from domestic dogs (Canis familiaris) and coyotes (Canis latrans)

The genus Mesocestoides Vaillant, 1863 includes tapeworms of uncertain phylogenetic affinities and with poorly defined life histories. We previously documented 11 cases of peritoneal cestodiasis in dogs (Canis familiaris L.) in western North America caused by metacestodes of Mesocestoides spp. In the current study, DNA sequences were obtained from metacestodes collected from these dogs (n = 10), as well as proglottids from dogs (n = 3) and coyotes (Canis latrans Say, 1823 [n = 2]), and tetrathyridia representing laboratory isolates of M. corti (n = 3), and these data were analyzed phylogenetically. Two nuclear genetic markers, 18S ribosomal DNA and the second internal-transcribed spacer (ITS 2), were sequenced. Phylogenetic analysis of the 18S rDNA data recovered a monophyletic group composed of all samples of Mesocestoides spp., distinct from closely related outgroup taxa (Amurotaenia Akhmerov, 1941 and Tetrabothrius Rudolphi, 1819). Initial analysis of the ITS 2 data resolved 3 clades within Mesocestoides. Two proglottids from dogs formed a basal clade, a second clade was represented by tetrathyridial isolates, and a third clade included all other samples. Interpretation of these data from an apomorphy-based perspective identified 6 evolutionary lineages. We also assessed whether metacestodes from dogs (n = 4) are capable of asexual proliferation in laboratory mice. One tetrathyridial and 2 acephalic isolates from dogs proliferated asexually. Further investigation is warranted to determine which of the lineages represent distinct species and to determine the life history strategies of Mesocestoides spp.     

CWD prions remain infectious after passage through the digestive system of coyotes (Canis latrans)

ABSTRACT

Chronic wasting disease (CWD) is a geographically expanding prion disease of wild and captive cervids in North America. Disease can be transmitted directly, animal to animal, or indirectly via the environment. CWD contamination can occur residually in the environment via soil, water, and forage following deposition of bodily fluids such as urine, saliva, and feces, or by the decomposition of carcasses. Recent work has indicated that plants may even take up prions into the stems and leaves. When a carcass or gut pile is present in the environment, a large number of avian and mammalian species visit and consume the carrion. Additionally, predators like coyotes, likely select for disease-compromised cervids. Natural cross-species CWD transmission has not been documented, however, passage of infectious prion material has been observed in the feces of crows. In this study we evaluated the ability of CWD-infected brain material to pass through the gastrointestinal tract of coyotes (Canis latrans) following oral ingestion, and be infectious in a cervidized transgenic mouse model. Results from this study indicate that coyotes can pass infectious prions via their feces for at least 3 days post ingestion, demonstrating that mammalian scavengers could contribute to the translocation and contamination of CWD in the environment.     

Serologic survey for canine infectious diseases among sympatric swift foxes (Vulpes velox) and coyotes (Canis latrans) in southeastern Colorado

Swift foxes (Vulpes velox) and coyotes (Canis latrans) are sympatric canids distributed throughout many regions of the Great Plains of North America. The prevalence of canid diseases among these two species where they occur sympatrically is presently unknown. From January 1997 to January 2001, we collected blood samples from 89 swift foxes and 122 coyotes on the US Army Pi?on Canyon Maneuver Site, Las Animas County, SE Colorado (USA). Seroprevalence of antibodies against canine parvovirus (CPV) was 71% for adult (> 9 mo old) and 38% for juvenile (< or = 9 mo old) swift foxes. Adult (<1 yr old) and juvenile (<1 yr old) coyotes had a seroprevalence for CPV of 96% and 78%, respectively. Presence of antibodies against canine distemper virus (CDV) was 5% for adult foxes and 0% for juvenile foxes. Seroprevalence of CDV was 46% for adult coyotes and 18% for juvenile coyotes. No swift foxes had canine adenovirus (CAV) antibodies, whereas 81% and 63% of adult and juvenile coyotes, respectively, had antibodies for CAV. Seroprevalence of antibodies against Yersinia pestis was 68% among adult foxes and 34% among juvenile swift foxes. Seroprevalence of Y. pestis antibodies was 90% and 70% for adult and juvenile coyotes, respectively. No swift foxes had antibodies against Francisella tularensis, whereas seroprevalence was 4% among both adult and juvenile coyotes. Antibodies against CPV and plague were common in both species, whereas antibodies against CDV and CAV were more prevalent in coyotes compared to swift foxes.     

Using faecal DNA sampling and GIS to monitor hybridization between red wolves (Canis rufus) and coyotes (Canis latrans)

The US Fish and Wildlife Service's (USFWS) Red Wolf Recovery Program recognizes hybridization with coyotes as the primary threat to red wolf recovery. Efforts to curb or stop hybridization are hampered in two ways. First, hybrid individuals are difficult to identify based solely on morphology. Second, managers need to effectively search 6000 km(2) for the presence of coyotes and hybrids. We develop a noninvasive method to screen large geographical areas for coyotes and hybrids with maternal coyote ancestry by combining mitochondrial DNA sequence analysis of faeces (scat) and geographic information system (GIS) technology. This method was implemented on the Alligator River National Wildlife Refuge (1000 km(2)) in northeastern North Carolina. A total of 956 scats were collected in the spring of 2000 and 2001 and global positioning system (GPS) coordinates were recorded. Seventy-five percent of the scats were assigned to species and five coyote/hybrid scats were detected. Placement of scat location coordinates on a map of the experimental population area revealed that four of the coyote/hybrid scats were detected within the home ranges of sterilized hybrids. The other coyote/hybrid scat indicated the presence of a previously unknown individual. We suggest this method be expanded to include more of the experimental population area and be optimized for use with nuclear markers to improve detection of hybrid and back-crossed individuals.     

Daily activity patterns of coyotes (Canis latrans) in a tropical deciduous forest of western Mexico

We studied the activity patterns of the coyote (Canis latrans) in a tropical deciduous forest in the Mexican Pacific coast over 3 years. Fifteen coyotes (six females, nine males) were fitted with radio-collars equipped with activity sensors to determine the influence of seasonality (dry vs. wet), gender (males vs. females) and diel intervals (dusk, night, dawn, and day) on activity patterns. We found differences in activity patterns between diel intervals, but the only pair of diel intervals that showed significant differences was dawn (more active) vs. day (less active). We found no differences due to sex or season on any of the four studied diel intervals. Coyote activity patterns in this tropical forest could be responding to prey availability, human avoidance or thermoregulation.     

Fine‐scale movements and behaviors of coyotes (Canis latrans) during their reproductive period

In canids, resident breeders hold territories but require different resources than transient individuals (i.e., dispersers), which may result in differential use of space, land cover, and food by residents and transients. In the southeastern United States, coyote (Canis latrans) reproduction occurs during spring and is energetically demanding for residents, but transients do not reproduce and therefore can exhibit feeding behaviors with lower energetic rewards. Hence, how coyotes behave in their environment likely differs between resident and transient coyotes. We captured and monitored 36 coyotes in Georgia during 2018–2019 and used data from 11 resident breeders, 12 predispersing residents (i.e., offspring of resident breeders), and 11 transients to determine space use, movements, and relationships between these behaviors and landcover characteristics. Average home range size for resident breeders and predispersing offspring was 20.7 ± 2.5 km² and 50.7 ± 10.0 km², respectively. Average size of transient ranges was 241.4 ± 114.5 km². Daily distance moved was 6.3 ± 3.0 km for resident males, 5.5 ± 2.7 km for resident females, and 6.9 ± 4.2 km for transients. We estimated first‐passage time values to assess the scale at which coyotes respond to their environment, and used behavioral change‐point analysis to determine that coyotes exhibited three behavioral states. We found notable differences between resident and transient coyotes in regard to how landcover characteristics influenced their behavioral states. Resident coyotes tended to select for areas with denser vegetation while resting and foraging, but for areas with less dense vegetation and canopy cover when walking. Transient coyotes selected areas closer to roads and with lower canopy cover while resting, but for areas farther from roads when foraging and walking. Our findings suggest that behaviors of both resident and transient coyotes are influenced by varying landcover characteristics, which could have implications for prey.     

Size‐assortative choice and mate availability influences hybridization between red wolves (Canis rufus) and coyotes (Canis latrans)

Anthropogenic hybridization of historically isolated taxa has become a primary conservation challenge for many imperiled species. Indeed, hybridization between red wolves (Canis rufus) and coyotes (Canis latrans) poses a significant challenge to red wolf recovery. We considered seven hypotheses to assess factors influencing hybridization between red wolves and coyotes via pair‐bonding between the two species. Because long‐term monogamy and defense of all‐purpose territories are core characteristics of both species, mate choice has long‐term consequences. Therefore, red wolves may choose similar‐sized mates to acquire partners that behave similarly to themselves in the use of space and diet. We observed multiple factors influencing breeding pair formation by red wolves and found that most wolves paired with similar‐sized conspecifics and wolves that formed congeneric pairs with nonwolves (coyotes and hybrids) were mostly female wolves, the smaller of the two sexes. Additionally, we observed that lower red wolf abundance relative to nonwolves and the absence of helpers increased the probability that wolves consorted with nonwolves. However, successful pairings between red wolves and nonwolves were associated with wolves that maintained small home ranges. Behaviors associated with territoriality are energetically demanding and behaviors (e.g., aggressive interactions, foraging, and space use) involved in maintaining territories are influenced by body size. Consequently, we propose the hypothesis that size disparities between consorting red wolves and coyotes influence positive assortative mating and may represent a reproductive barrier between the two species. We offer that it may be possible to maintain wild populations of red wolves in the presence of coyotes if management strategies increase red wolf abundance on the landscape by mitigating key threats, such as human‐caused mortality and hybridization with coyotes. Increasing red wolf abundance would likely restore selection pressures that increase mean body and home‐range sizes of red wolves and decrease hybridization rates via reduced occurrence of congeneric pairs.     

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

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 0.01 mg/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.     

Neospora caninum-like oocysts observed in feces of free-ranging red foxes (Vulpes vulpes) and coyotes (Canis latrans)

The aim of this study was to examine the feces of free-ranging foxes and coyotes for the presence of Neospora caninum oocysts. Feces were collected from 271 foxes and 185 coyotes in the Canadian province of Prince Edward Island, processed by sucrose flotation, and examined by light microscopy for the presence of coccidian oocysts. In 2 fox and 2 coyote samples, oocysts morphologically and morphometrically similar to oocysts of N. caninum were observed. DNA was extracted from these samples and subjected to nested polymerase chain reaction (PCR) using primers to the N. caninum-specific Nc5 genomic sequence. Through DNA sequencing, alignment of the sequences of at least 3 clones from each isolate to sequences deposited in GenBank revealed 95-99% similarity to the Nc5 sequence of N. caninum. PCR using primers specific for Hammondia heydorni failed to yield an amplification product from these DNA samples.     

Plague surveillance by serological testing of coyotes (Canis latrans) in Los Angeles County, California.

Sera from 19 (5.6%) of 338 coyotes (Canis latrans) collected in Los Angeles County, California between 1986 and 1990 had antibodies against Yersinia pestis using the passive hemagglutination test. Coyotes were excellent sentinels of plague activity in Los Angeles County. Enzootic plague declined dramatically in the county during the 5-yr period.