Adult Wolves Research Articles

Ultrasonographic characteristics of the reproductive tract and serum progesterone and estradiol concentrations in captive female red wolves (Canis rufus) with and without reproductive tract disease.

OBJECTIVE To describe ultrasonographic characteristics of the reproductive tract and serum progesterone and estradiol concentrations in captive female red wolves (Canis rufus) with and without reproductive tract disease. DESIGN Prospective study. ANIMALS 13 adult female red wolves. PROCEDURES Wolves with varying parity and history of contraceptive treatment were anesthetized to facilitate ultrasonographic examination and measurement of the reproductive tract and blood collection for determination of serum progesterone and estradiol concentrations in December 2011 and June 2012. Additionally, during the December evaluation, fine-needle aspirate samples of the uterus were obtained for cytologic evaluation. Measurements were compared between wolves with and without reproductive tract disease and between wolves that had and had not received a contraceptive. RESULTS 7 of 13 wolves had or developed reproductive tract disease during the study. Ranges for measurements of reproductive tract structures overlapped between ultrasonographically normal and abnormal tracts, but measurements for abnormal tracts were generally greater than those for normal tracts. The ultrasonographic diagnosis was consistent with the histologic diagnosis for reproductive tracts obtained from wolves that were sterilized, were euthanized, or died during the study. Cytologic results for fine-needle aspirate samples of the uterus and serum progesterone and estradiol concentrations were unable to distinguish wolves with and without reproductive tract disease. Reproductive tract disease was not associated with parity or contraceptive administration. CONCLUSIONS AND CLINICAL RELEVANCE The ultrasonographic images, reproductive tract measurements, and descriptions of reproductive tract lesions provided in this study can be used as diagnostic guidelines for the treatment and management of red wolves with reproductive tract disease.

The role of domestication and experience in \u2018looking back\u2019 towards humans in an unsolvable task

A key element thought to have changed during domestication is dogs’ propensity to communicate with humans, particularly their inclination to gaze at them. A classic test to measure this is the ‘unsolvable task’, where after repeated successes in obtaining a reward by object-manipulation, the animal is confronted with an unsolvable version of the task. ‘Looking back’ at humans has been considered an expression of dogs seeking help. While it occurs more in dogs than in socialized wolves, the level of exposure to human communication also appears to play a role. We tested similarly raised adult wolves and mixed breed dogs, pet dogs and free-ranging dogs. Unlike previous studies, as well as species and levels of socialization, we included ‘persistence’ in trying to solve the task as a potential explanatory factor. Wolves were more persistent than all dog groups. Regardless of socialization or species, less persistent animals looked back sooner and longer. Free-ranging dogs, despite little exposure to dog-human communication, behaved similarly to other dogs. Together, results suggest that basic wolf-dog differences in motivation and exploration may override differences in human-directed behaviour when animals are equally socialized, and that once the human is considered a social partner, looking behaviour occurs easily.

Selecting habitat to what purpose? The advantage of exploring the habitat–fitness relationship

AbstractMeasures of reproductive success have been recognized in many fields as essential tools to assess the status of populations, species, and communities. However, difficulties in gathering data on reproductive success often prevent researchers from taking advantage of the information offered by those measures. For example, most of habitat selection studies do not include reproductive success in their analysis even though doing so would highly improve our understanding of the habitat selection process. In our study, we aimed to assess to what extent habitat selection choices made by adult individuals are directed to increase their annual reproductive success. We tested this idea by first developing habitat selection models and then relating the results of those models to two measures of reproductive success. Using wolves, Canis lupus, as the study species, we determined that not all habitat selection choices performed by adult wolves were related to their annual reproductive success. The results varied also in relation to the measure of reproductive success used in the analysis and other individual‐, group‐, and population‐level factors. Likely, adult female wolves select habitat characteristics to increase not only their annual reproductive success but also their lifetime reproductive success, for example, by ensuring their own survival and reproductive abilities in subsequent years. Our study suggests that a variety of motivations may govern habitat choices performed by adult individuals and including different measures of fitness in habitat selection studies can improve our understanding of these complex processes.

Motivational Factors Underlying Problem Solving: Comparing Wolf and Dog Puppies' Explorative and Neophobic Behaviors at 5, 6, and 8 Weeks of Age.

Background: Wolves have been shown to be better in independent problem-solving tasks than dogs, however it is unclear whether cognitive or motivational factors underlie such differences. In a number of species problem solving has been linked to both persistence in exploration and neophobia, suggesting both these aspects may underlie dog-wolf differences in problem solving. Indeed adult wolves have been shown to be more likely to approach a novel object and more persistent in their investigation of it, but also slower in making contact with it and more fearful of it than dogs.Methods: In the current study we investigated potential differences in equally-raised dogs' and wolves' explorative and neophobic behaviors in a novel environment and with novel objects at 5, 6, and 8 weeks of age.Results: Results showed that wolves were more persistent in exploring both the environment and the objects than dogs, and this was the case at all ages. There were no differences in the frequency of fear-related behaviors and time spent in proximity to humans. Stress-related behaviors were similarly expressed at 5 and 6 weeks, although wolves showed a higher frequency of such behaviors at 8 weeks.Discussion: Overall, results with puppies confirm those with adult animals: wolves appear to be more explorative than dogs. Such motivational differences need to be taken into account when comparing dogs and wolves in cognitive tasks.

CRANIOMETRIA EM LOBOS-GUARÁ Chrysocyon brachyurus ILLIGER, 1815 (CARNIVORA, CANIDAE)

Resumo Os objetivos do presente trabalho foram obter mensurações em crânios de Chrysocyon brachyurus adultos, caracterizar valores craniométricos para a espécie e observar se a classificação craniométrica de cães domésticos é adequada para o lobo-guará. Foram utilizados sete crânios de lobo-guará adultos, sem distinção de sexo. Determinou-se a localização de nove pontos craniométricos utilizados em cães domésticos para o lobo-guará. Os pontos foram referência para as 18 medidas craniométricas utilizadas para o cálculo de seis índices craniométricos. Os índices craniométricos são: cefálico 96,147 ± 3,89 mm, crânio facial 1,06 ± 0,20 mm, do neurocrânio 61,68 ± 1,83 mm, facial 100,06 ± 3,36 mm, basal 29,79 ± 1,18 mm, e do forame magno 89,25 ± 7,82 mm. A classificação em braquicefálico, dolicocefálico ou mesaticefálico não se adequa a Chrysocyon brachyurus.

A comparison between wolves, Canis lupus, and dogs, Canis familiaris, in showing behaviour towards humans

Both human and nonhuman primates use imperative pointing to request a desired object from another individual. Gaze alternation often accompanies such pointing gestures, and in species that have no hands this can in itself function as imperative pointing. Dogs have exceptional skills in communicating with humans. The early development of these skills is suggested to have been facilitated by domestication. Adult wolves socialized with humans can use human-provided information to find food in various situations, but it is unclear whether they would use gaze alternation to show their human partner a target location they cannot reach on their own. In our experiment, we tested wolves and dogs in a task where they could indicate an out-of-reach food location to one of two human partners. One partner reacted in a cooperative way and gave the food hidden in the indicated location to the subject whereas the other responded in a competitive way and ate the food herself. Our results suggest that wolves, as well as dogs, use ‘showing’ behaviours to indicate a food location to a human partner, and that both can adjust their communication to the cooperativeness of their human partners, showing more indicating signals in the presence of the cooperative partner than in the presence of the competitive one. We conclude that wolves and dogs, both kept in packs under the same conditions, can use humans as cooperative partners, and point imperatively in order to receive a desired out-of-reach object. It seems that intensive socialization with humans enables both wolves and dogs to communicate cooperatively about a food location with humans, most probably relying on skills that evolved to promote social coordination within their packs.

Intraocular pressure and Schirmer tear test values in maned wolf (Chrysocyon brachyurus)

Abstract: The purpose of this study was to establish baseline data on lacrimal quantity (STT-1) and intraocular pressure (IOP) in captive maned wolves. Ten healthy adult maned wolves were contained with a snare pole and muzzle and kept in decubitus of the left side. STT-1 measurement was performed on the lateral third of the lower conjunctival sac for one minute. The cornea was desensitized and intraocular pressure was measured with an tonopen. Average STT-1 in both eyes was 11±5mm.min-1, with no statistical difference between the left and right eye (p=0.960). Average IOP in both eyes was 20±6mmHg, with no statistical difference between the left and right eye (p=0.836). Average STT-1 was lower than, and IOP was the same as normal levels found in dogs. There was no statistical difference in the age of the animals, and STT-1 and IOP values. In the present paper, average maned wolf STT-1 levels were lower compared with those found in dogs, while the IOP was the same in maned wolves as in dogs. Due to the increased incidence in providing emergency care for maned wolf victims of road kill and fires, determination reference values of ocular parameters may improve the correct diagnosis and treatment of the disease.

Exploring Differences in Dogs' and Wolves' Preference for Risk in a Foraging Task.

Both human and non-humans species face decisions in their daily lives which may entail taking risks. At the individual level, a propensity for risk-taking has been shown to be positively correlated with explorative tendencies, whereas, at the species level a more variable and less stable feeding ecology has been associated with a greater preference for risky choices. In the current study we compared two closely related species; wolves and dogs, which differ significantly in their feeding ecology and their explorative tendencies. Wolves depend on hunting for survival with a success rate of between 15 and 50%, whereas free-ranging dogs (which make up 80% of the world dog population), are largely scavengers specialized on human produce (i.e., a more geographically and temporally stable resource). Here, we used a foraging paradigm, which allowed subjects to choose between a guaranteed less preferred food vs. a more preferred food, which was however, delivered only 50% of the time (a stone being delivered the rest of time). We compared identically raised adult wolves and dogs and found that in line with the differing feeding ecologies of the two species and their explorative tendencies, wolves were more risk prone than dogs.

Play Behavior in Wolves: Using the '50:50' Rule to Test for Egalitarian Play Styles.

Social play is known as a cooperative interaction between individuals involving multiple mechanisms. However, the extent to which the equality of individuals’ play styles affects the interaction has not been studied in many species. Dyadic play between wolf puppies, as well as between puppies and adults, was studied to investigate both self-handicapping and offensive behaviors to determine the extent to which wolves engage in play styles where one individual does not dominate the play. Our results did not support the hypothesized ‘50:50’ rule, which suggests that more advantaged individuals should show higher rates of self-handicapping behaviors in order to facilitate play with others. Adult wolves performed significantly less self-handicapping behaviors than their puppy partners, and they performed significantly more offensive behaviors than their puppy partners. While the ‘50:50’ rule was not supported at any time during our study period, dyads consisting of two puppies had significantly more equal play than dyads consisting of one puppy and one adult. These results suggest that wolf puppies are more likely to play on equal terms with similarly-aged play partners, while the dominance status of the partners dictates offensive and self-handicapping behaviors between animals of different ages.

Treatment of a forelimb fracture and rehabilitation of a free-ranging Iberian Wolf (Canis lupus signatus)

Abstract: The surgical treatment of an exposed compounded comminuted fracture of the right radius and ulna in a free-ranging adult female Iberian Wolf (Canis lupus signatus) with an osteosynthesis plate and screws and subsequent post-operative care are described. The evolution of the fracture healing was very similar to those expected in a dog of the same size. The prompt surgical intervention and a proper housing, feeding and wound management adapted to a free-ranging wolf, in view to reduce manipulation and post-operative complications, allowed the subsequent rehabilitation and release of the animal. After 10th post-operative weeks the wolf was fitted with a Global Positioning System (GPS) for wildlife tracking collar and released in the same area where it has been caught. GPS telemetry data showed that the animal covered increasingly large distances confirming a complete functionality of the right thoracic limb and its successfully return to the wild. This report could constitute the first detailed report of a long bone fracture treatment in a free-ranging wolf and its successfully rehabilitation, release and adaptation to the wild.

Wolf visitations close to human residences in Finland: The role of age, residence density, and time of day

Large carnivorous mammals, such as the gray wolf (Canis lupus) have been recently expanding to human-dominated landscapes in many regions. Although wolves tend to avoid human infrastructure, visitations close to human residences might be unavoidable in territories that are highly fragmented by residential areas. House yard visits are of particular concern: according to the Finnish legislation, wolves that repeatedly approach within 150m from the nearest residential building can legally be killed for human safety. We analyzed the average distance from house yards and probability of house yard visitations by wolves against sex, age class, time of the day, season and house density for 25 territorial GPS-tracked wolves in Finland. Generally, wolves avoid houses — with mean distances higher than from random locations in the territory. This difference became higher with decreasing house density for sub-adults while for adults this difference decreased slightly with decreasing house density. Probability of visitation in house-yards increased with increasing house densities, was far higher at night than in the daytime, a difference that was greater with increasing house density. Sub-adults visited house-yards more often than adult wolves in the first summer after spring dispersal from the natal pack to a territory, but there was no difference in winter. The indication that wolves learn within a season to avoid moving to near residential buildings in human-dominated territories is when the territory becomes more familiar to wolves which is a noteworthy result for the management.

Wolf-caribou dynamics within the central Canadian Arctic

The severity of recent declines of barren-ground caribou (Rangifer tarandus groenlandicus) across the central Canadian Arctic has led to harvest restrictions and concerns about population recovery. Wolves (Canis lupus) are the main predator of barren-ground caribou; however, the extent that wolves influence the decline and recovery of caribou herds is unknown. Such uncertainty confounds management responses (e.g., reducing harvest, predator control). We investigated wolf–caribou dynamics on the summer range of barren-ground caribou in the Northwest Territories and Nunavut, Canada (i.e., Bathurst caribou herd). Our primary objective was to test for a numerical response of wolves to changes in the abundance and spatial distribution of caribou. Caribou experienced a >90% decline in abundance over the study period (1996–2014). Using long-term data sets (1996–2012), we developed regression models to investigate relationships between abundance indices of wolves and range-use patterns of caribou. We monitored the movements of adult female wolves fitted with global positioning system (GPS) collars representing individual packs throughout the 2013 and 2014 denning periods. We also investigated pup recruitment, an index of population decline, at a time of low caribou abundance. Finally, we developed a series of stochastic population models to understand how pup recruitment influenced wolf densities on the Bathurst range over the period of caribou decline. As caribou abundance decreased, the late-summer distribution of the Bathurst herd contracted toward the calving ground. These movements correlated with low rates of wolf pup recruitment and high den abandonment, suggesting a regulatory mechanism whereby wolf reproductive success was limited by the low availability of caribou within the denning areas. Furthermore, these data suggested a numerical response, where wolf densities decreased as caribou numbers declined. In 2014, wolf density was estimated at <4 wolves/1,000 km2. Our results suggest that these wolves exhibited a relatively strong numerical response to a single, declining prey base. Given the continued decline in the Bathurst caribou herd, the tundra wolf population on the Bathurst range has likely declined below our 2014 estimate. © 2016 The Wildlife Society.

A standardized framework for examination of oral lesions in wolf skulls (Carnivora: Canidae: Canis lupus)

Abstract Oral lesions in wolves (Carnivora: Canidae: Canis lupus) are usually reported in a nonstandardized manner, and often only a few abnormalities are indicated. This approach has likely led to underreporting of oral lesions, thus limiting our ability to interpret wolf health conditions and thus making comparisons across geographical and taxonomic groups difficult. Here, we present a standardized oral exam protocol to examine wolf skulls for their oral lesions. Using this protocol, we analyzed 40 skulls of adult wild Middle East wolves representing 1,680 teeth. Six wolves were Canis lupus arabs, 34 were Canis lupus pallipes. Only 3 skulls showed no oral lesions. We were able to identify a large range of oral lesions and refined subclasses, exceeding the variety of what has been reported on wolf oral lesions so far. No statistical differences were found in the type and number of lesions between the 2 subspecies of wolves. Therefore, the lesions were pooled in subsequent analyses. This standardized protocol should provide a useful framework to assess oral lesions in wolf skulls, facilitating rigorous comparisons across geographic and taxonomic groups.

Activity, movement, home range and habitat use of an adult gray wolf in a Mediterranean landscape of northern Greece

AbstractWe present the results of a study on the activity patterns of a wolf in northwestern Greece (2011–2012). The home range of the wolf was 460.5 km

Aggression and hierarchical steepness inhibit social play in adult wolves

In canids, play dynamics seem to be more affected by dominance hierarchy rather than cooperative social bonds. To test this hypothesis we studied a colony of grey wolves (Canis lupus lupus). We quantified the dynamics of aggression and hierarchical changes in two periods (Sample 1 and Sample 2). Sample 2 was characterized by higher level of aggressiveness and by a more strict and steep linear hierarchy. The negative correlation between rank distance and play frequency characterizing both periods and the higher play asymmetry in Sample 2 suggest that rank rules dictate play rules thus highlighting the competitive side of wolf play behaviour. The overall affiliation rates showed no variation between the two samples. Yet, play performance was modified. In Sample 2, wolves reduced playful activity, limited the number of players per session and avoided playing during high competition contexts. Our findings support the hypothesis that wolf play is modulated by dominance relationships more than by cooperative social bonds.

Infanticide in wolves: seasonality of mortalities and attacks at dens support evolution of territoriality

Evidence for territoriality is usually correlative or post hoc as we observe the results of past selection that are challenging to detect. Wolves (Canis lupus) are considered territorial because of competition for food (resource defense), yet they exhibit classic intrinsic behaviors of social regulation (protection against infanticide). This emphasis on prey and infrequent opportunity to observe wild wolf behavior has led to little investigation into the causes of or competitive underpinnings in the evolution of wolf territoriality. We report 6 cases of territorial wolf packs attacking neighboring packs at or near their den; 2 attacks were observed in detail. In all cases, except perhaps one, the attacking pack killed adult wolves either at the den or near it; in 4 cases, pups were probably lost. Loss of pups led to future loss of territory and in one case pack cessation. Intraspecific killing (measured in collared adults only) peaked in April, the month when pups were born and helpless in dens, even thou...

Canine distemper in endangered Ethiopian wolves.

The Ethiopian wolf (Canis simensis) is the world's rarest canid; ≈500 wolves remain. The largest population is found within the Bale Mountains National Park (BMNP) in southeastern Ethiopia, where conservation efforts have demonstrated the negative effect of rabies virus on wolf populations. We describe previously unreported infections with canine distemper virus (CDV) among these wolves during 2005-2006 and 2010. Death rates ranged from 43% to 68% in affected subpopulations and were higher for subadult than adult wolves (83%-87% vs. 34%-39%). The 2010 CDV outbreak started 20 months after a rabies outbreak, before the population had fully recovered, and led to the eradication of several focal packs in BMNP's Web Valley. The combined effect of rabies and CDV increases the chance of pack extinction, exacerbating the typically slow recovery of wolf populations, and represents a key extinction threat to populations of this highly endangered carnivore.

Philopatry and dispersal in the wolf population (Canis lupus L.)

This paper studies the manifestation of philopatry and dispersal in wolves at the level of family, population group (the Central Forest Reserve), and population (Tver oblast). The importance of a den area for a wolf in the formation of the territorial structure is shown. The “philopatric” behavior of 35 wolves from seven families in a completing circle of flags is analyzed: 32 individuals (16 adult and 16 young wolves from different families) crossed flags toward a den, and only three chose a different direction. This behavior was typical for the entire population group of wolves both for young individuals born and raised in this place and for adult wolves (both resident wolves and their children who have created here new pairs and then families). Attention is focused on the role of “dispersant” wolves in 1972–1982: a rapid increase in the population was caused by internal reserves due to the dispersal of juveniles for short distances. Analysis of the available field and literature data shows that dispersers “transfer” ecological, behavioral, spatial functional, and structural features of a family; i.e., they are bearers of its traditions.

Predator‐dependent functional response in wolves: from food limitation to surplus killing

The functional response of a predator describes the change in per capita kill rate to changes in prey density. This response can be influenced by predator densities, giving a predator-dependent functional response. In social carnivores which defend a territory, kill rates also depend on the individual energetic requirements of group members and their contribution to the kill rate. This study aims to provide empirical data for the functional response of wolves Canis lupus to the highly managed moose Alces alces population in Scandinavia. We explored prey and predator dependence, and how the functional response relates to the energetic requirements of wolf packs. Winter kill rates of GPS-collared wolves and densities of cervids were estimated for a total of 22 study periods in 15 wolf territories. The adult wolves were identified as the individuals responsible for providing kills to the wolf pack, while pups could be described as inept hunters. The predator-dependent, asymptotic functional response models (i.e. Hassell-Varley type II and Crowley-Martin) performed best among a set of 23 competing linear, asymptotic and sigmoid models. Small wolf packs acquired >3 times as much moose biomass as required to sustain their field metabolic rate (FMR), even at relatively low moose abundances. Large packs (6-9 wolves) acquired less biomass than required in territories with low moose abundance. We suggest the surplus killing by small packs is a result of an optimal foraging strategy to consume only the most nutritious parts of easy accessible prey while avoiding the risk of being detected by humans. Food limitation may have a stabilizing effect on pack size in wolves, as supported by the observed negative relationship between body weight of pups and pack size.

How hot is too hot? Live-trapped gray wolf rectal temperatures and 1-year survival

The ability of physically restrained and anesthetized wolves to thermoregulate is lessened and could lead to reduced survival, yet no information is available about this subject. Therefore, we analyzed rectal temperatures related to survival 1 year post-capture from 173 adult (non-pup) gray wolves (Canis lupus) captured in modified foot-hold traps for radiocollaring during June–August, 1988–2011, in the Superior National Forest of northeastern Minnesota, USA. The maximum observed rectal temperature (“maxtemp,” ° F, ° C) in each wolf during capture (x¯ = 104.0, 40.0; SD = 2.0, 1.1; min. = 95.9, 35.5; max. = 108, 42.2) was not a significant predictor of survival to 1 year post-capture. Although no weather or morphometric variable was a significant predictor of maxtemps, wolves initially anesthetized with ketamine–xylazine rather than telazol®–xylazine averaged higher maxtemps. This information does not fully address possible effects of high body temperatures related to live-capture and handling of wolves, but it does provide a useful waypoint for future assessments of this relationship and a reassurance to wildlife practitioners that the maxtemps observed in our study did not appear to affect 1-year survival. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.