A comparative test of inequity aversion in domestic dogs (Canis familiaris) and dingoes (Canis dingo)

Despite much recent empirical work on inequity aversion in nonhuman species, many questions remain about its distribution across taxa and the factors that shape its evolution and expression. Past work suggests that domestic dogs (Canis familiaris) and wolves (Canis lupus) are averse to inequitable resource distributions in contexts that call upon some degree of training such as 'give paw' and 'buzzer press' tasks. However, it is unclear whether inequity aversion appears in other canid species and in other experimental contexts. Using a novel inequity aversion task that does not require specific training, this study helps address these gaps by investigating inequity aversion in domestic dogs and a closely related but non-domesticated canid, the dingo (Canis dingo). Subjects were presented with equal and unequal reward distributions and given the opportunity to approach or refuse to approach allocations. Measures of interest were (1) subjects' refusal to approach when getting no food; (2) approach latency; and (3) social referencing. None of these measures differed systematically across the inequity condition and control conditions in either dogs or dingoes. These findings add to the growing literature on inequity aversion in canids, providing data from a new species and a new experimental context. Additionally, they raise questions about the experimental features that must be in place for inequity aversion to appear in canids.

The successful reintroduction of African wild dogs (Lycaon pictus) to Gorongosa National Park, Mozambique

Large carnivores have experienced widespread extirpation and species are now threatened globally. The ecological impact of the loss of large carnivores has been prominent in Gorongosa National Park, Mozambique, after most were extirpated during the 1977–92 civil war. To remedy this, reintroductions are now being implemented in Gorongosa, initiating with endangered African wild dogs (Lycaon pictus), hereafter ‘wild dogs’. We describe the first transboundary translocation and reintroduction of founding packs of wild dogs to Gorongosa over a 28-month study period and evaluate the success of the reintroduction based on five key indicator categories. We also assess how wild dog space use and diet influenced their success. We found that pre-release, artificial pack formation in holding enclosures aided group cohesion and alpha pair establishment. Post-release, we also observed natural pack formations as a result of multiple dispersal events. Founder and naturally formed packs produced pups in two of the three breeding seasons and packs successfully recruited pups. Survival rate for all wild dogs was 73% and all mortality events were from natural causes. Consequently, the population grew significantly over the study period. All indicators of success were fully achieved and this study documents the first successful reintroduction of wild dogs into a large, unfenced landscape in Mozambique and only the second on the continent. Potential mechanisms underlying these early successes were the avoidance of habitats intensively used by lions, dietary partitioning with lion, avoidance of human settlements, and Gorongosa’s management strategy. We predict further population expansion in Gorongosa given that 68% of the park is still unused by wild dogs. This expansion could be stimulated by continued reintroductions over the short- to medium-term. Recovery of wild dogs in Gorongosa could aid in the re-establishment of a larger, connected population across the greater Gorongosa-Marromeu landscape.

Beauty or beast? Farmers' dualistic views and the influence of aesthetic appreciation on tolerance towards black-backed jackal and caracal

Various species of wild, adaptable, medium-sized carnivores occur outside of protected areas, often coming into contact with people and their domestic animals. Negative human-carnivore interactions can lead to antagonistic attitudes and behavior directed at such species. In the South African Karoo, a semi-arid rangeland, the predation of small-livestock by mesopredators is common and farmers typically use a combination of non-lethal and lethal methods to try and prevent livestock losses. We used ethnographic field observations and semi-structured interviews as part of a mixed methods approach, including the quantitative and qualitative analysis of farmers' narratives to illustrate the nuanced ways in which sheep farmers relate to the two mesopredators that consume the most livestock on their farms; black-backed jackal and caracal. Overall, farmers attributed negative characteristics to jackal and caracal but farmers' narratives provided evidence of complex perceptions in that the animals were admired as well as disliked. Both species were seen as charismatic due to traits such as their physical appearance, their "cunning" nature and their remarkable adaptability to human activities, including lethal control. Aesthetic appreciation was an important predictor of tolerance towards both species whereas negative attitudes were associated with the perception that mesopredators should only occur within protected areas. Attitudes towards jackals also appeared to have been affected by cultural representations of them as "thieves". We showed that perceiving mesopredators as beautiful increased the average marginal probability of a farmer tolerating them, and that this strong relationship held when controlling for other covariates such as livestock predation. We advocate the importance of understanding the cultural and aesthetic aspects of predators and considering existing positive dimensions of human-wildlife relationships that may encourage increased farmers' tolerance, which might promote coexistence.

Selection and Constraints in the Ecomorphological Adaptive Evolution of the Skull of Living Canidae (Carnivora, Mammalia)

The association between phenotype and ecology is essential for understanding the environmental drivers of morphological evolution. This is a particularly challenging task when dealing with complex traits, such as the skull, where multiple selective pressures are at play and evolution might be constrained by ontogenetic and genetic factors. I integrate morphometric tools, comparative methods, and quantitative genetics to investigate how ontogenetic constraints and selection might have interacted during the evolution of the skull in extant Canidae. The results confirm that the evolution of cranial morphology was largely adaptive and molded by changes in diet composition. While the investigation of the adaptive landscape reveals two main selective lines of least resistance (one associated with size and one associated with functional shape features), rates of evolution along size were higher than those found for shape dimensions, suggesting the influence of constraints on morphological evolution. Structural modeling analyses revealed that size, which is the line of most genetic/phenotypic variation, might have acted as a constraint, negatively impacting dietary evolution. Constraints might have been overcome in the case of selection for the consumption of large prey by associating strong selection along both size and shape directions. The results obtained here show that microevolutionary constraints may have played a role in shaping macroevolutionary patterns of morphological evolution.

Dog appeasing pheromone prevents the androgen surge and may reduce contact dominance and active submission after stressful interventions in African wild dogs (Lycaon pictus)

The endangered African wild dog (AWD; Lycaon pictus) is a highly social canid living in packs with a separate male and female hierarchy. Immobilisation, handling and translocations are acute stressors for AWDs, however such interventions are often needed for species management. In addition, new pack formation or temporary pack separation can lead to an increase in intra-pack aggression. The goal of this double-blinded placebo-controlled study conducted in captive zoo populations was to evaluate whether dog appeasing pheromone (DAP) reduces behavioural stress and faecal glucocorticoid metabolite levels (fGCM) normally associated with pack separation, immobilisation and reintroduction (SIR), and to assess whether this reduces aggressive behaviours and faecal androgen metabolite levels (fAM). Four packs (n = 11 males) were treated with DAP and 4 packs (n = 12 males) were treated with a placebo solution, applied at the end of anaesthesia. Behavioural interactions as well as fGCM and fAM were determined from 3 days before until 4-6 days after SIR. No effect of DAP on fGCM was observed, however, fAM increased after SIR in placebo but not DAP treated animals. Moreover, on the day of reintroduction, DAP treated packs tended to have lower rates of contact-dominance and active-submission behaviour, but higher rates of non-contact dominance behaviour. As these effects could decrease the risk of agonistic interactions, DAP may be a useful tool to help manage new pack formations and temporary pack separation.

Landscape correlates of space use in the critically endangered African wild dog Lycaon pictus

Human-carnivore conflict can threaten human life and livelihoods, leading to retaliation that negatively affects carnivore conservation. The endangered African wild dog Lycaon pictus is prone to human-carnivore conflict. Therefore, it is imperative to understand which landscape features are associated with African wild dog occurrence since selection or avoidance of these features could predict the levels of conflict. We investigated resource selection in the African wild dog in relation to four anthropogenic landscape features (livestock density, agriculture, roads and human land use) within the landscape that may pose a mortality risk, as well as one natural feature (nature reserves). We compared spatio-temporal space use patterns of four African wild dog packs in north-eastern South Africa. Data were collected from one collared individual per pack. These packs constituted approximately 10% of the total remaining African wild dog population in South Africa. Two packs occurred outside of the Kruger National Park and had access to multiple areas with farmland and other anthropogenic features, whereas the remaining two packs mainly occurred within the boundaries of the Kruger National Park but made occasional forays outside of park boundaries. Utilising Resource Selection Functions and GIS analyses, we found that agricultural landscape features, roads and nature reserves were important predictors of African wild dog occurrence for all four packs. In addition to potential conflict with farmers, high odds of occurrence on roads with fast-moving traffic and road mortality was highlighted as a concern for three of the packs. While farms and areas that house livestock were readily available, pack presence occurred in areas with few farms and low livestock densities, pointing to avoidance of areas where human-carnivore conflict and resulting mortality could occur. Our study highlights potential threats to the persistence of the African wild dog, which can be used to inform future conservation efforts of the species.

Physiological impacts of housing maned wolves (Chrysocyon brachyurus) with female relatives or unrelated males

The maned wolf is a threatened canid species native to South America. Previous studies have suggested the species exhibits induced ovulation. In captive breeding facilities, reproductive success is low while rates of neonatal mortality are high. Females that are not recommended for breeding are frequently housed together. However there has never been a systematic study of the reproductive consequences of co-housing females. This study was conducted for three purposes, to: (1) corroborate the presence of induced ovulation, (2) determine whether elevated cortisol is implicated in neonatal pup mortality, and (3) evaluate the endocrine correlates of group housed females. Using fecal hormone monitoring for estrogen, progesterone, and cortisol, 43 cycles from 33 female maned wolves were studied from 2002 to 2015. Females were categorized by their reproductive status: pregnant and successfully raised pups (PR; n = 11), pregnant with neonatal pup demise within 3 days (PL; n = 7), housed with a male but no signs of breeding or pregnancy (PP; n = 10), housed singly (S; n = 8), or housed with related females (F; n = 7). Estrogen and progestagen remained at baseline for all females not housed with a male (S, F), while elevations consistent with ovulation were seen in females housed with a male (PP, PL, PR). Compared to PR females, PL individuals showed similar cortisol levels throughout the cycle and slightly lower progesterone levels during gestation. As for the effect of co-housing related females, F females showed estrogen and progesterone levels lower even than S females while cortisol levels were elevated compared to all other groups. These findings support the previous evidence of induced ovulation in the maned wolf. Although elevated cortisol does not seem to be implicated in pup loss, a non-significant trend towards lower progesterone during gestation could be implicated. Future studies should assess depressed progesterone levels as a correlate to neonatal pup mortality. Female maned wolves housed with related females experience suppressed reproductive hormones and elevated adrenal hormones. Therefore, a more systematic study of hormonal and behavioral correlates to co-housing with related females is warranted.

Sneeze to leave: African wild dogs (Lycaon pictus) use variable quorum thresholds facilitated by sneezes in collective decisions

In despotically driven animal societies, one or a few individuals tend to have a disproportionate influence on group decision-making and actions. However, global communication allows each group member to assess the relative strength of preferences for different options among their group-mates. Here, we investigate collective decisions by free-ranging African wild dog packs in Botswana. African wild dogs exhibit dominant-directed group living and take part in stereotyped social rallies: high energy greeting ceremonies that occur before collective movements. Not all rallies result in collective movements, for reasons that are not well understood. We show that the probability of rally success (i.e. group departure) is predicted by a minimum number of audible rapid nasal exhalations (sneezes), within the rally. Moreover, the number of sneezes needed for the group to depart (i.e. the quorum) was reduced whenever dominant individuals initiated rallies, suggesting that dominant participation increases the likelihood of a rally's success, but is not a prerequisite. As such, the 'will of the group' may override dominant preferences when the consensus of subordinates is sufficiently great. Our findings illustrate how specific behavioural mechanisms (here, sneezing) allow for negotiation (in effect, voting) that shapes decision-making in a wild, socially complex animal society.

Evaluation of the Applicability of Different Age Determination Methods for Estimating Age of the Endangered African Wild Dog (Lycaon Pictus)

African wild dogs (Lycaon pictus) are endangered and their population continues to decline throughout their range. Given their conservation status, more research focused on their population dynamics, population growth and age specific mortality is needed and this requires reliable estimates of age and age of mortality. Various age determination methods from teeth and skull measurements have been applied in numerous studies and it is fundamental to test the validity of these methods and their applicability to different species. In this study we assessed the accuracy of estimating chronological age and age class of African wild dogs, from dental age measured by (i) counting cementum annuli (ii) pulp cavity/tooth width ratio, (iii) tooth wear (measured by tooth crown height) (iv) tooth wear (measured by tooth crown width/crown height ratio) (v) tooth weight and (vi) skull measurements (length, width and height). A sample of 29 African wild dog skulls, from opportunistically located carcasses was analysed. Linear and ordinal regression analysis was done to investigate the performance of each of the six age determination methods in predicting wild dog chronological age and age class. Counting cementum annuli was the most accurate method for estimating chronological age of wild dogs with a 79% predictive capacity, while pulp cavity/tooth width ratio was also a reliable method with a 68% predictive capacity. Counting cementum annuli and pulp cavity/tooth width ratio were again the most accurate methods for separating wild dogs into three age classes (6-24 months; 25-60 months and > 60 months), with a McFadden's Pseudo-R2 of 0.705 and 0.412 respectively. The use of the cementum annuli method is recommended when estimating age of wild dogs since it is the most reliable method. However, its use is limited as it requires tooth extraction and shipping, is time consuming and expensive, and is not applicable to living individuals. Pulp cavity/tooth width ratio is a moderately reliable method for estimating both chronological age and age class. This method gives a balance between accuracy, cost and practicability, therefore it is recommended when precise age estimations are not paramount.

Scaling and Accommodation of Jaw Adductor Muscles in Canidae

The masticatory apparatus amongst closely related carnivoran species raises intriguing questions about the interplay between allometry, function, and phylogeny in defining interspecific variations of cranial morphology. Here we describe the gross structure of the jaw adductor muscles of several species of canid, and then examine how the muscles are scaled across the range of body sizes, phylogenies, and trophic groups. We also consider how the muscles are accommodated on the skull, and how this is influenced by differences of endocranial size. Data were collected for a suite of morphological metrics, including body mass, endocranial volume, and muscle masses and we used geometric morphometric shape analysis to reveal associated form changes. We find that all jaw adductor muscles scale isometrically against body mass, regardless of phylogeny or trophic group, but that endocranial volume scales with negative allometry against body mass. These findings suggest that head shape is partly influenced by the need to house isometrically scaling muscles on a neurocranium scaling with negative allometry. Principal component analysis suggests that skull shape changes, such as the relatively wide zygomatic arches and large sagittal crests seen in species with higher body masses, allow the skull to accommodate a relative enlargement of the jaw adductors compared with the endocranium. Anat Rec, 299:951-966, 2016. © 2016 The Authors The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology Published by Wiley Periodicals, Inc.

An Ecological Paradox: The African Wild Dog (Lycaon Pictus) Is Not Attracted to Water Points When Water Is Scarce in Hwange National Park, Zimbabwe

In dry biomes, spatio-temporal variation in surface water resource stocks is pervasive, with unknown effects on the ranging behaviour of large predators. This study assessed the effect of spatial variation in surface water resources on the ranging behaviour of the African wild dog (Lycaon pictus). We analyzed data for 1992 (dry year with 20 water points) and 2000 (wet year with 30 water points) against presence-only data for five packs of L. pictus in a part of Hwange National Park and adjacent smallholder communal farming areas in western Zimbabwe. Modelling the potential habitat for L. pictus using Maxent with distance from water points (Dw) and Normalized Difference Vegetation Index (NDVI) as predictor variables was successful for 2000 (AUC = 0.793) but not successful for 1992 (AUC = 0.423), with L. pictus probability of occurrence near water points being more for year 2000 than for year 1992. The predicted L. pictus range was wider in 1992 (~13888.1 km2) than in 2000 (~958.4 km2) (Test of Proportions, χ2 = 124.52, df = 1, P = 0.00). Using the 2nd order Multitype Nearest Neighbour Distance Function (Gcross), we also observed significant attraction between L. pictus and water points within only ~1km radius for 1992 but up to ~8km radius for 2000. Our study reinforced the notion that surface water resources attract wild dogs in the savannahs but paradoxically less so when water resources are scarce. In particular, our study furthers current understanding of the effects of changing water availability regimes on the endangered L. pictus, providing evidence that the endangered predator's home range encroaches into potential ecological traps (i.e., smallholder communal farming areas) when water resources are scarce.

Monitoring stress in captive and free-ranging African wild dogs (Lycaon pictus) using faecal glucocorticoid metabolites

An understanding of stress physiology is important for species management because high levels of stress can hamper reproduction and affect an individual's ability to cope with threats to their survival, such as disease and human-wildlife conflict. A commonly used indicator of stress, faecal concentrations of cortisol metabolites (FCM), can be used to assess the impact of social, biological and environmental factors. Measurements of FCM are particularly valuable for endangered species that are logistically challenging to study and where non-invasive techniques are preferred. As the second most endangered canid in Africa, the African wild dog (Lycaon pictus) has been the focus of considerable conservation research, yet there is still little understanding of factors associated with stress, in either captive or free-ranging populations. The present study therefore aimed to determine whether stress levels differ between captive and free-ranging populations, and to detect social, biological and environmental factors that are stressful in these populations. Faecal samples were collected from 20 captive and 62 free-ranging animals. Within free-ranging populations, the sexes differed significantly, but there was no effect of social status, age or breeding period for either sex. Captive females had higher FCM concentrations than free-ranging females. In captive populations, FCM concentrations differed among zoos and with reproductive status in females, but were not related to age class or group-housing structure. In conclusion, FCM is a useful indicator of stress and should be considered an integrative aspect of management, for both in situ and ex situ African wild dog populations.

Potential Sources of High Frequency and Biphonic Vocalization in the Dhole (Cuon alpinus)

Biphonation, i.e. two independent fundamental frequencies in a call spectrum, is a prominent feature of vocal activity in dog-like canids. Dog-like canids can produce a low (f0) and a high (g0) fundamental frequency simultaneously. In contrast, fox-like canids are only capable of producing the low fundamental frequency (f0). Using a comparative anatomical approach for revealing macroscopic structures potentially responsible for canid biphonation, we investigated the vocal anatomy for 4 (1 male, 3 female) captive dholes (Cuon alpinus) and for 2 (1 male, 1 female) wild red fox (Vulpes vulpes). In addition, we analyzed the acoustic structure of vocalizations in the same dholes that served postmortem as specimens for the anatomical investigation. All study dholes produced both high-frequency and biphonic calls. The anatomical reconstructions revealed that the vocal morphologies of the dhole are very similar to those of the red fox. These results suggest that the high-frequency and biphonic calls in dog-like canids can be produced without specific anatomical adaptations of the sound-producing structures. We discuss possible production modes for the high-frequency and biphonic calls involving laryngeal and nasal structures.

Enrichment options for African painted dogs (Lycaon pictus)

Best practices for carnivore enrichment encourage the diversity of species-typical behaviors, increased activity, and reduced stereotypic behavior; ideally considering the life-history and behavior of each species. African wild dogs (Lycaon pictus), or painted dogs, are social carnivores that have large home ranges and complex pack dynamics (e.g., variation in group size, relatedness, etc.). As there are relatively few studies on painted dog enrichment, the goal of this study was to compile a list of enrichment options used by institutions participating in the species survival plan (SSP). Representatives were asked to describe social groups (n = 45), enclosures (n = 21), enrichment practices (options, delivery frequency, perceived success), and overall best practices. Respondents (61%, n = 23) reported using options for all six enrichment categories recommended by the Canid Taxon Advisory Group: environmental enrichment devices, habitat, sensory, food, behavioral, and social. Perceived success was significantly higher for the food category, followed by the sensory and behavioral categories. All respondents reported delivering enrichment at least multiple times a month, and most reported multiple times per week. Enclosure size did not differ significantly for mixed-sex groups (n = 28) compared to single-sex groups (n = 17). We discuss respondents' suggestions for best practices and the need to record data to compare perceived success with actual behavioral effects, controlling for variation in group size and composition. Overall, respondents recommended a flexible approach, since not all painted dogs and groups respond in the same way to the enrichment options.

A pathological Late Pleistocene canid from San Sidero (Italy): implications for social- and feeding-behaviour

Evidence of diseases on vertebrate fossil bones can provide detailed information on many aspects of extinct animals. This study focused on pathological craniodental remains (left maxilla and dentary) referred to the canid Cuon alpinus unearthed from a Late Pleistocene karst filling deposit at San Sidero (Apulia, southern Italy). These fossils show clear evidence of a chronic periodontitis that caused the animal's death. Clinical diagnosis of the disease and the timing of its development have been defined on the basis of a veterinary odontostomatology approach, in addition to radiographic and tomographic techniques. From the initiation of the infection until death, a time span of at least 6 months occurred, and three main steps have been defined: (1) the bacterial infections of the buccal cavity turning into severe periodontitis, (2) the fracture of the lower carnassial and (3) the loss of teeth due to the worsening infection that deformed and/or eroded maxillary and mandibular bones and enlarged alveoli. The analysis of the palaeopathology also provides information about the biomechanics of the bite, on the feeding behaviour and on the relationships of injured members in a pack of Late Pleistocene canids.

Adrenal activity in maned wolves is higher on farmlands and park boundaries than within protected areas

In this study we measured excreted fecal corticoid metabolites (FCM) in maned wolves (Chrysocyon brachyurus) living within a protected reserve, on farmlands or in a boundary zone between the two habitats, and determined the impacts of season and reproductive status on adrenal activity. Feces were collected within a national park (n=191 samples), a park boundary zone (n=39) and on nearby farmlands (n=27), processed and analyzed by enzyme immunoassay. FCM amounts from samples collected on farmlands were higher (P<0.05) than in those collected inside the reserve and from the boundary zone. In relation to seasonality, FCM were elevated (P<0.05) in spring (September-November) when wolf pairs were raising young. We then divided the samples collected during breeding season (March-August) into cycling females and male/non-cycling females based on fecal progesterone: fecal testosterone ratio. FCM concentrations of the former collected inside the park were higher than (P<0.05) than the latter group. However, there were no differences in FCM levels between the two groups for samples collected in the boundary zone and on farmlands. Furthermore, FCM concentrations of male/non-cycling females samples collected on farmlands were 2- to 5-fold higher (P<0.05) than in counterparts collected inside the park. The consistently high FCM concentrations in samples collected on farmlands indicate that, in addition to seasonality, gender and reproductive status, anthropogenic pressures also contribute to elevating adrenal steroid for individuals living in altered habitat.

Seasonal changes in steroid hormone profiles, body weight, semen quality, and the reproductive tract in captive African wild dogs (Lycaon pictus) in South Africa

Characterization of reproductive seasonality in the African wild dog (Lycaon pictus) could assist reintroduction programs. Male wild dogs (n=14) were assessed quarterly (January, mid-summer; April, late summer; August, late winter; November, early summer) for serum testosterone, body weight, testicular and prostatic volume, preputial gland measurement, and ejaculate characteristics. Bi-monthly fecal samples were collected from male (n=11) and female (n=4) wild dogs for analysis of fecal androgens and progestagens. Fecal androgens were higher in early summer (246.4 ± 14.5 ng/g) than in early winter (218.6 ± 13.4 ng/g). Serum testosterone was higher in mid-summer (1.4 ± 0.3 ng/ml) than in late winter (0.7 ± 0.1 ng/ml). Number of spermatozoa per ejaculate was greatest in late summer (301.4 ± 39.3 × 10(6)). Other semen parameters peaked in mid-summer (pH: 7.4; progressive motility: 85.0 ± 0.1%; live spermatozoa: 81.0 ± 16%; normal morphology: 71.5 ± 8.2%). Total testicular and prostatic volume were greater during summer (testicular: 36.7 ± 4.2 cm(3); prostatic: 12.0 ± 1.9 cm(3)) than winter (testicular: 25.2 ± 1.9 cm(3); prostatic: 5.8 ± 0.8 cm(3)). Preputial pendulance also was greater in summer (7.1 ± 0.5 cm; n=9) than winter (5.9 ± 0.2 cm). Baseline fecal progestagen metabolites were 6.2 ± 2.5 μg/g and peak fecal progestagen metabolites were 14.7 ± 2.8 μg/g. Copulations resulting in pregnancies (n=2) occurred in late summer and gestation was 71 days. Female wild dogs were seasonally monoestrous with mating in summer and winter. In conclusion, wild dogs are reproductively seasonal with improvement in male reproductive variables during summer and a bi-phasic seasonal pattern to female receptivity.

Effectiveness of scat-detection dogs in determining species presence in a tropical savanna landscape

Most protected areas are too small to sustain populations of wide-ranging mammals; thus, identification and conservation of high-quality habitat for those animals outside parks is often a high priority, particularly for regions where extensive land conversion is occurring. This is the case in the vicinity of Emas National Park, a small protected area in the Brazilian Cerrado. Over the last 40 years the native vegetation surrounding the park has been converted to agriculture, but the region still supports virtually all of the animals native to the area. We determined the effectiveness of scat-detection dogs in detecting presence of five species of mammals threatened with extinction by habitat loss: maned wolf (Chrysocyon brachyurus), puma (Puma concolor), jaguar (Panthera onca), giant anteater (Myrmecophaga tridactyla), and giant armadillo (Priodontes maximus). The probability of scat detection varied among the five species and among survey quadrats of different size, but was consistent across team, season, and year. The probability of occurrence, determined from the presence of scat, in a randomly selected site within the study area ranged from 0.14 for jaguars, which occur primarily in the forested areas of the park, to 0.91 for maned wolves, the most widely distributed species in our study area. Most occurrences of giant armadillos in the park were in open grasslands, but in the agricultural matrix they tended to occur in riparian woodlands. At least one target species occurred in every survey quadrat, and giant armadillos, jaguars, and maned wolves were more likely to be present in quadrats located inside than outside the park. The effort required for detection of scats was highest for the two felids. We were able to detect the presence for each of five wide-ranging species inside and outside the park and to assign occurrence probabilities to specific survey sites. Thus, scat dogs provide an effective survey tool for rare species even when accurate detection likelihoods are required. We believe the way we used scat-detection dogs to determine the presence of species can be applied to the detection of other mammalian species in other ecosystems.

Gross morphometric study of the eyeball and tongue of the Nigerian local dog

This study investigates the morphometry of two sense organs, the eyeball and tongue, of the Nigerian local dog (11 males, 14 females), all aged 2 years and above. The samples were grouped according to gender and weight (up to 12 kg or above that weight). The average values obtained for the weights of the left and right eyeballs and the tongue were 3.77 +/- 0.51 g, 3.68 +/- 0.74 g and 2.96 +/- 0.38 g respectively, while the length of the tongue, its thickness and width at the root and apex were 14.20 +/- 2.29 cm, 0.87 +/- 0.30 cm, and 0.21 +/- 0.05 cm respectively. The circumferences of the eyeballs (antero-posterior, mediolateral and peri-orbital) were all found to be higher in females, except the antero-posterior circumference of left eye, in spite of heavier eyeballs in males. Also, the females showed a wider rima oris and higher values for most of the tongue measurements. A positive correlation existed between the weight of the animal and that of the head and tongue, while a negative correlation was observed between the body weight and the weight of the eyeballs. This report highlights the presence of sexual dimorphism and mild lateral asymmetry in this rarely reported breed of dog. The data obtained from this study may find application in feeding physiology, ophthalmic clinical manipulations and comparative anatomy.

Physiological Constraints and Latitudinal Breeding Season in the Canidae

Physiological strategies that maximize reproductive success may be phylogenetically constrained or might have a plastic response to different environmental conditions. Among mammals, Canidae lend themselves to the study of these two influences on reproductive physiology because all the species studied to date have been characterized as monestrous (i.e., a single ovulatory event per breeding season), suggesting a phylogenetic effect. Greater flexibility could be associated with environments that are less seasonal, such as the tropics; however, little is known for many of the species from this region. To compensate for this lack of data, two regressions were done on the length of the reproductive season relative to the latitudinal distribution of a species: one with raw data and another with phylogenetically independent contrasts. There was a significant negative relationship, independent of phylogeny, with canids that have longer breeding seasons occurring at lower latitudes. In contrast, the pervasiveness of monestrus within Canidae appears to be phylogenetically constrained by their pairing/packing life and is most likely associated with monogamy. The persistence of the monestrous condition is supported by a captive study where a tropical canid, the fennec fox, Vulpes zerda, never exhibited polyestrous cycles despite a constant photoperiod (12L : 12D).

Similarities of the neuronal circuit for the induction of fictive vomiting between ferrets and dogs

Previous studies suggested that the following neuronal circuit participates in the induction of vomiting by afferent vagal stimulation in decerebrated paralyzed dogs: (1) afferent fibers of the vagus nerve, (2) neurons of the solitary nucleus (NTS), (3) neurons of the prodromal sign center near the semicompact part of the nucleus ambiguus (scAMB), (4) neurons of the central pattern generator in the reticular area adjacent to the compact part of nucleus ambiguus (cAMB), (5) respiratory premotor neurons in the caudal medulla, (6) motor neurons of the diaphragm and abdominal muscles. However, the commonality of this neuronal circuit in different species has not yet been clarified. Thus, this study was conducted to clarify this point. This study clarified for the first time that fictive vomiting in decerebrated paralyzed ferrets could be induced by vagal stimulation, and could be identified by centrifugal activity patterns of the phrenic and abdominal muscle nerves. The distributions of c-Fos immunoreactive neurons in the NTS, scAMB and cAMB areas in ferrets that exhibited fictive vomiting were denser than those in ferrets that did not. Application of the nonNMDA receptor antagonist into the 4th ventricle produced the reversible suppression of fictive vomiting. The NK1 receptor immunoreactive puncta were found in the reticular area adjacent to the scAMB. Microinjections of NK1 receptor antagonist into the reticular areas on both sides abolished fictive vomiting. All these results in the ferrets are identical with results previously obtained in dogs and cats. Therefore, this suggests that the above neuronal circuit commonly participates in the induction of emesis in these animal species.

Studies of male reproduction in captive African wild dogs (Lycaon pictus)

Implementation of assisted breeding in the captive African wild dog is restricted by a current lack of knowledge on their reproductive physiology and the apparent difficulty of effectively manipulating the complex social dynamic of the pack in order to conduct reproductive procedures. In this study, we describe protocols for the safe and repeated capture and restraint of the African wild dog (n=7) as well as techniques for assessment of male reproductive function, semen collection and preservation. In a serendipitous finding, captive African wild dogs appeared to display significant seasonal change in male reproduction. Testicular volume and tone, spermatorrhea and the ability to collect semen by electroejaculation all increased significantly during late summer and then subsequently declined by early spring. While there were no detectable seasonal changes in testosterone concentration in the population as whole, the alpha-dominant male in both years of the study, had a highly elevated testosterone concentration compared to subordinate males. Semen collection by electroejaculation during the late summer was most effective in peri-pubertal males (15 months) when all seven electroejaculates were of adequate quality for cryopreservation. In the second breeding season (27 months), there were numerous changes in the pack hierarchy and electroejaculation was not as successful (3/7). The characteristics of electroejaculated semen collected in the breeding season are described for seven animals including the first descriptions and incidence of sperm abnormalities in the species. Semen (n=7) was frozen using a Tris-citrate fructose buffer and final egg yolk and glycerol concentration of 20% and 4%, respectively. Sperm were loaded into 0.25 mL straws, frozen in liquid nitrogen vapor and then thawed at 37 degrees C. Initial post-thaw survival of spermatozoa was encouraging (% motile: 31.8+/-5.8%; rate: 2.8+/-0.3; % intact plasma membranes: 33.4+/-5.3% and the % of damaged acrosomes: 4.4+/-1.5%) but following 2 h incubation at 37 degrees C, post-thaw survival declined markedly.

Immobilization of free-ranging maned wolf (Chrysocyon brachyurus) with tiletamine and zolazepam in central Brazil

A tiletamine hydrochloride-zolazepam hydrochloride combination was used successfully to immobilize 27 free-ranging maned wolves (Chrysocyon brachyurus) at a mean dose of 2.77+/-0.56 (mean+/-SD) mg/kg. The induction time ranged from 3-15 min. Animals remained immobilized for periods of 48.56 +/-12.65 min. Compulsive licking, excessive salivation, muscle twitching, muscle tremors, tachypnea, and bradycardia were observed associated with the induction of the anesthesia in 13 of 27 maned wolves. Muscle twitching, pedal withdrawal reflex, muscle tremors, and ataxia were observed during recovery in three (11%) maned wolves. There were no significant differences in heart rates (P = 0.44), respiratory rates (P = 0.82), and rectal temperatures (P = 0.54) recorded at 5, 15, and 25 min after induction at these dosages. The tiletamine hydrochloride-zolazepam hydrochloride combination was shown to be an effective and safe immobilizing agent for free-ranging maned wolves.

The seminiferous epithelium cycle and daily spermatic production in the adult maned wolf (Chrysocyon brachyurus, Illiger, 1811)

The duration of the seminiferous epithelium cycle was estimated in adult maned wolves (Chrysocyon brachyurus, Illiger, 1811), by applying intratesticular injections with tritiated thymidine. The total duration of the seminiferous epithelium cycle in this species was calculated in 8.99 days. So, taking into account that approximately 4.5 cycles of the seminiferous epithelium are necessary for the whole spermatogenesis process to complete, the production of spermatozoa from one spermatogonia will take about 40.45 days. The duration of the spermiogenesis was calculated to be 12.3 days. The eight stages of the seminiferous epithelium cycle were described by the tubular morphology method, which is based either on the form and position of the spermatid nuclei and the occurrence of meiotic divisions. The values of the relative frequency for the pre-meiotic, meiotic and post-meiotic phases in this species were 3.5, 0.78 and 4.8 days, respectively. The maned wolf produces about 29 million spermatozoa a day for each testis gram, therefore being classified among the species provided with a high spermatogenetic efficiency.

Species resilience in Pleistocene hominids that traveled far and ate widely: An analogy to the wolf-like canids

Morphological and genetic analyses have yet to resolve the question of whether more than one species of Homo existed contemporaneously in the Pleistocene. In an effort to contribute a process-related perspective to hominid phylogenetic reconstruction, this paper uses an analogy to the northern wolf-like canids (the wolves and coyotes) to ask the question, How many Homo species should there be, given their likely behavioral profile(s)? In contrast to earlier comparisons to social carnivores which sought to illuminate specific aspects of hominid behavioral ecology, this paper explores behavioral constraints on the process of speciation itself. The analogy suggests that because Pleistocene Homo probably exhibited high habitat tolerance, they would not have had the opportunity to speciate, especially in Africa. In contrast to an earlier single-species hypothesis based on competitive exclusion between sympatric hominid species, this paper explores constraints on the process of speciation under conditions of temporary allopatry.

A note on the effect of the full moon on the activity of wild maned wolves, Chrysocyon brachyurus

It is well established in the scientific literature that animal prey species reduce their activity at times of high predation risk. In the case of nocturnal animals this occurs when there is a full moon; however, the response of predators to the changes in their prey behaviour is relatively unknown. Two responses are possible: (1) increase in search effort to maintain food intake; or (2) decrease in distance travelled due to either: (a) an effort to conserve energy or (b) increased kill efficiency. Using GPS tracking collars we monitored the distances travelled (which is representative of search effort) by three maned wolves during the night of the full and new moon for five lunar cycles (during the dry season). A Wilcoxon matched-paired test showed that the maned wolves travelled significantly less during the full compared to the new moon (p < 0.05). On average, during the 10 h of darkness during a full moon maned wolves travelled 1.88 km less than on a new moon. These data suggest that maned wolves respond to temporally reduced prey availability by reducing their distance travelled.

Culture strategies for maturation of carnivore oocytes

In vitro maturation (IVM) of carnivore oocytes is still under investigation. It is well known that oocytes must accomplish nuclear and cytoplasmic maturation to acquire developmental competence. However, little is known about mechanisms regulating these events in carnivore oocytes. Consequently, IVM rates are still lower than those obtained in other species. To improve results in carnivores, two strategies have to be investigated: one finalized towards preserving in vitro functional integrity and potentiality to accomplish complete maturation of cumulus-oocyte complexes (COCs), the other finalized towards providing culture conditions adequate for sustaining complete maturation of these oocytes. Thus, modifications of the culture environment during IVM, by addition of substances that stimulate endogenous systems of cell defence and modulate the intracellular levels of regulatory molecules, or by use of sequentially different culture systems, are interesting strategies for enhancing viability and competence in terms of complete maturation of carnivore oocytes. This review is focused on recent advances in the study of these aspects developed in feline and/or canine oocytes.