Habitat Use by Sympatric Jaguars and Pumas Across a Gradient of Human Disturbance in Belize

Jaguars (Panthera onca) and pumas (Puma concolor) are sympatric across the entire jaguar range, where they coexist in increasingly fragmented landscapes under threat of persecution mainly in response to livestock predation. Pumas are known to inhabit a greater variety of natural habitats than jaguars, but little is known about the influence of anthropogenic factors on the coexistence of these two similar-sized cats. This study compares habitat use of jaguars and pumas in Belize, Central America, using 1380 jaguar and puma photo captures from 3 yr of camera trapping, comprising 64–74 individual jaguars and an unknown number of pumas. Jaguars and pumas did not differ in their use of a large block of relatively homogenous secondary rain forest. However, pumas were scarce outside this forest block, whereas jaguars were detected throughout the human-influenced landscape. Reasons for this discrepancy may include differential tolerance to human disturbance, and resource limitation for pumas outside the forest block. Intra-specific variation in jaguar activity in the form of sex-dependent habitat use was detected across the landscape. Male jaguars were detected at more locations than female jaguars and more frequently at each location, with a declining difference from a 50-fold greater detection in the protected forest, through forest buffer, savannah, pastures, to negligible difference in the disturbed forest.     

Jaguar and Puma Activity Patterns and Predator‐Prey Interactions in Four Brazilian Biomes

Jaguars (Panthera onca) and pumas (Puma concolor) coexist throughout the Neotropics. Using camera trapping in four Brazilian biomes, we compare the daily activity patterns of the jaguar and puma, and their relationships with their main prey species. We used a kernel density method to quantify daily activity patterns and to investigate overlap between these predators and their main prey. Both cats showed intensive nocturnal and crepuscular activity (0.69 and 0.14 kernel density, respectively, for jaguars; 0.68 and 0.19 kernel density, respectively, for pumas). Only in the Pantanal did we observe a pattern of concentrated diurnal activity for both species. We found little temporal segregation between jaguars and pumas, as they showed similar activity patterns with high coefficients of overlapping (average ?₁ = 0.86; SE = 0.15). We also observed a significant overlap between the activity patterns of the predators and their main prey species, suggesting that both predators adjust their activity to reduce their foraging energy expenditure. Our findings suggest that temporal partitioning is probably not a generalized mechanism of coexistence between jaguars and pumas; instead, the partitioning of habitat/space use and food resources may play a larger role in mediating top predator coexistence. Knowledge about these behavior aspects is crucial to elucidating the factors that enable coexistence of jaguars and pumas. Furthermore, an understanding of their respective activity periods is relevant to management and associated research efforts.     

Food Habits and Livestock Depredation of Sympatric Jaguars and Pumas in the Iguaçu National Park Area, South Brazil

Understanding coexistence between sympatric felines with similar body sizes, such as jaguars Panthera onca and pumas Puma concolor , requires knowledge of the way these predators consume and partition food resources. Yet the importance of livestock predation on jaguar and puma coexistence is poorly known. I investigated food habits and patterns of livestock depredation of jaguar and pumas in the Iguaçu National Park (INP) in southern Brazil. From 1997 to 2001, I collected scats opportunistically on trails and roads in INP and visited ranches on the border of INP. I found that jaguars relied mostly on large and medium-sized wild prey species, while pumas concentrated on medium-sized prey species. Livestock was the fifth most frequent prey found in jaguar scats but the most important one in terms of biomass consumed. Jaguar and puma diets differed significantly when all prey items were compared and also when livestock was excluded from the jaguar diet. Jaguar predation on livestock was considerably higher than predation by pumas. However, predation was not substantial relative to availability of livestock, and cattle likely constitute an alternative source of prey for jaguars. Degree of diet overlap between jaguar and puma in INP suggests that coexistence was likely driven by exploitative competition through some degree of food partitioning. My results highlight the importance of more actions toward increasing numbers of large ungulates to preserve the population of jaguars in INP.     

Differential impact of landscape transformation on pumas (Puma concolor) and jaguars (Panthera onca) in the Upper Paraná Atlantic Forest

Aim Jaguars and pumas, being similar in size and behaviour, are the largest felids of the Neotropics. However, pumas appear to be more resistant to human impacts. Our objective was to compare the response of both species with human impacts at a regional scale in a highly modified region where both species had continuous distribution in the past. Location The Upper Parana Atlantic Forest (UPAF). Methods Pumas and jaguars presence‐only data were used in an Ecological Niche Factor Analysis (ENFA). From the total number of records, we resampled 95 records of each species 10 times to characterize and compare their habitat requirements, built habitat‐suitability maps and examined interspecific differences in niche parameters related to present landscape characteristics. Results Both species showed high dependence on native forest and habitat protection, and low tolerance to anthropogenic environments. However, jaguars showed higher differences between their optimal habitat and the available landscape (mean ± SD; marginality M = 2.290 ± 0.072) and lower tolerance to deviations from their optimal habitat (tolerance T = 0.596 ± 0.013) than pumas (M = 1.358 ± 0.067, P < 0.001; T = 0.742 ± 0.022, P < 0.001). Although their niches highly overlapped (Pianka’s O = 0.746 ± 0.069), pumas’ higher tolerance resulted in a larger area covered by suitable patches of habitat with higher connectivity. All jaguar‐suitable areas were also suitable for pumas; however, 44 ± 8% of puma‐suitable areas were unsuitable or marginal for jaguars. Main conclusions Pumas showed more tolerance than jaguars to human impacts at a regional scale in the UPAF, a pattern also observed at local and continental scales. Although the proximate factors responsible for the differential response of pumas to human‐altered environments seem to be similar at all spatial scales (e.g. broader trophic niche than jaguars), the resultant spatial configuration of suitable habitat at a regional scale might be another important factor determining puma persistence and higher jaguar demands on conservation efforts.     

Spatial requirements of jaguars and pumas in Southern Mexico

Understanding how large felids use space is essential for the design of conservation plans that are required for their survival. Jaguars (Panthera onca) and pumas (Puma concolor) are the largest felids in the Neotropics, and they are sympatric throughout the entire range of the jaguar. However, there is very little information about the spatial requirements of these two species in the tropical rainforests of Central America. Using satellite GPS collars, we compared the spatial ecology of jaguars and pumas in a tropical rainforest in southern Mexico. We found that jaguars had home ranges that were 2–6 times larger than those of pumas. The mean annual home range was 181.4 ± 4.0 km² for female jaguars and 431.6 ± 152.6 km² for males. Annual home range for the only female puma tracked was 34.3 km², and 72.0 ± 85.2 km² for males. Jaguars and pumas with overlapping home ranges showed little overlap of core areas and avoided using the same sites at the same time, which suggested that territoriality and avoidance were in play. Further evidence of avoidance was derived from our observation that pumas exhibited greater movement during the lightest periods of the day and jaguars moved most during the darkest. This temporal separation probably facilitates coexistence. Our data suggest that habitat destruction and fragmentation has more severe effects on jaguars than on pumas. According to our estimates, patches of at least 180 km² of primary forest are required to meet the annual spatial requirements of female jaguars. Thus, to conserve jaguars in this region, large tracts of primary forest should be preserved. Importantly, this population of jaguars depends on the adequate preservation of connectivity between natural reserves in Mexico and Guatemala.     

Use of Camera-Trapping to Estimate Puma Density and Influencing Factors in Central Brazil

Abstract: We used remotely triggered cameras to collect data on Puma (Puma concolor) abundance and occupancy in an area of tropical forest in Brazil where the species' status is poorly known. To evaluate factors influencing puma occupancy we used data from 5 sampling campaigns in 3 consecutive years (2005 to 2007) and 2 seasons (wet and dry), at a state park and a private forest reserve. We estimated puma numbers and density for the 2007 sampling data by developing a standardized individual identification method. We based individual identification on 1) time-stable parameters (SP; physical features that do not change over time), and 2) time-variable parameters (VP; marks that could change over time such as scars and botfly marks). Following individual identification we established a capture-recapture history and analyzed it using closed population capture-mark-recapture models. Puma capture probability was influenced by camera placement (roads vs. trails), sampling year, and prey richness. Puma occupancy was positively associated with species richness and there was a correlation between relative puma and jaguar (Panthera onca) abundance. Identifications enabled us to generate 8 VP histories for each photographed flank, corresponding to 8 individuals. We estimated the sampled population at 9 pumas (SE = 1.03, 95% CI = 8–10 individuals) translating to a density of 3.40 pumas/100 km². Information collected using camera-traps can effectively be used to assess puma population size in tropical forests. As habitat progressively disappears and South American felines become more vulnerable, our results support the critical importance of private forest reserves for conservation.     

A non-invasive faecal survey for the study of spatial ecology and kinship of solitary felids in the Viruá National Park,Amazon Basin

Jaguars and pumas are the largest felids in the Americas. Information about these two species is scarce, especially where both species are sympatric. We studied the use and selection of macrohabitats, spatial segregation and kinship in jaguars and pumas in the Viruá National Park (Amazonian lowlands) by non-invasive genetic analyses of faecal samples. Seven different jaguars (six males and one female) and nine different pumas (five males and four females) were identified. We found space use segregation between the two species, with pumas using mostly forested habitats and jaguars using open habitats slightly more than the forested ones. This result is unexpected, since previous studies have found that pumas favour more open habitats than jaguars. The results suggest that jaguars use the areas in a more random manner, corresponding to the habits of a dominant generalist species, whereas pumas use the area to reduce encounter rates with jaguars. Nevertheless, both species mainly used areas near upland forest-flooding habitats. Some kinship categories were supported with a p < 0.05 in 57 and 83% of the pair comparisons between the identified jaguars and the identified pumas, respectively. Non-invasive genetic analysis of faeces was useful to study the spatial ecology of solitary, rare and cryptic species in the Amazon.     

Ocelot Population Status in Protected Brazilian Atlantic Forest

Forest fragmentation and habitat loss are detrimental to top carnivores, such as jaguars (Panthera onca) and pumas (Puma concolor), but effects on mesocarnivores, such as ocelots (Leopardus pardalis), are less clear. Ocelots need native forests, but also might benefit from the local extirpation of larger cats such as pumas and jaguars through mesopredator release. We used a standardized camera trap protocol to assess ocelot populations in six protected areas of the Atlantic forest in southeastern Brazil where over 80% of forest remnants are < 50 ha. We tested whether variation in ocelot abundance could be explained by reserve size, forest cover, number of free-ranging domestic dogs and presence of top predators. Ocelot abundance was positively correlated with reserve size and the presence of top predators (jaguar and pumas) and negatively correlated with the number of dogs. We also found higher detection probabilities in less forested areas as compared to larger, intact forests. We suspect that smaller home ranges and higher movement rates in smaller, more degraded areas increased detection. Our data do not support the hypothesis of mesopredator release. Rather, our findings indicate that ocelots respond negatively to habitat loss, and thrive in large protected areas inhabited by top predators.     

Dietary separation of sympatric carnivores identified by molecular analysis of scats

We studied the diets of four sympatric carnivores in the flooding savannas of western Venezuela by analysing predator DNA and prey remains in faeces. DNA was isolated and a portion of the cytochrome b gene of the mitochondrial genome amplified and sequenced from 20 of 34 scats. Species were diagnosed by comparing the resulting sequences to reference sequences generated from the blood of puma (Puma concolor), jaguar (Panthera onca), ocelot (Leopardus pardalus) and crab-eating fox (Cerdocyon thous). Scat size has previously been used to identify predators, but DNA data show that puma and jaguar scats overlap in size, as do those of puma, ocelot and fox. Prey-content analysis suggests minimal prey partitioning between pumas and jaguars. In field testing this technique for large carnivores, two potential limitations emerged: locating intact faecal samples and recovering DNA sequences from samples obtained in the wet season. Nonetheless, this study illustrates the tremendous potential of DNA faecal studies. The presence of domestic dog (Canis familiaris) in one puma scat and of wild pig (Sus scrofa), set as bait, in one jaguar sample exemplifies the forensic possibilities of this noninvasive analysis. In addition to defining the dietary habits of similar size sympatric mammals, DNA identifications from faeces allow wildlife managers to detect the presence of endangered taxa and manage prey for their conservation.     

Jaguar (Panthera onca) feeding ecology: distribution of predator and prey through time and space

Jaguars Panthera onca inhabiting tropical or subtropical evergreen moist forest have often been classified as opportunistic predators because they consume prey relative to its availability. However, these studies failed to address simultaneously the distribution of predator and prey through time and space, which may lead to an incomplete or erroneous understanding of jaguar foraging strategies. In this study, we reconstructed jaguar diet from scat, and used camera traps to investigate jaguar prey availability and the distribution of jaguar and its prey through space and time. We focused our examination of predator–prey temporal and spatial relations on forest infrastructure comprising man-made paths, small mammal trails, tapir Tapirus bairdi trail and trail-less, forested areas as they represent distinct habitats for prey selection. Overall, we observed high overlap between the prey used and available, suggestive of opportunistic foraging. However, jaguars exhibited selective tendencies in discriminating between larger prey. Jaguars used collared peccary Tayassu tajacu greater than its availability, while preying upon the equally abundant and similarly distributed white-lipped peccary Tayassu pecari and tapir less than predicted based upon availability. Armadillo Dasypus novemcinctus and paca Agouti paca , 56.6% of total consumption, were consumed relative to availability but exhibited low spatial overlap with jaguar. Armadillo and paca used trail-less, forested areas and small mammal trails not used by jaguar and were photographed more frequently at greater distances from man-made paths, major thoroughfares for jaguars. This study suggests that although forest jaguars use prey relative to its abundance, jaguars may rely on foraging strategies other than chance encounters for exploiting prey.     

同域栖息的美洲虎和美洲狮存在竞争吗?

美洲虎( Panthera onca)和美洲狮( Puma concolor)是中美洲和南美洲大部区域共存的大型猫科动物,其共存理论得到研究验证。本文作者回顾了有关文献,认为同域分布的美洲虎和美洲狮存在生境和猎物分化,提出热带美洲狮具有较小体型以利用较小的猎物并减少与美洲虎竞争的假设。研究支持美洲虎和美洲狮的空间相互回避概念,但两者猎物之间分化的研究结果不相吻合。尽管如此,文献认为新热带界美洲狮体型较小只是反映了在进化过程中偏于利用较小猎物的事实,而与美洲虎的竞争无关。人类的影响会引起美洲虎和美洲狮的共存。在新热带界环境中,美洲虎由于依赖特定猎物而较大程度地受到人类引起的猎物种群下降之影响,但美洲狮由于可以偏向利用小型猎物或猎物多样化而得到补偿,从而能更好地适应人类的影响。     

Drivers of jaguar (Panthera onca) and puma (Puma concolor) predation on endangered primates within a transformed landscape in southern Mexico

Human pressures have increasingly placed keystone species, such as large cats, under threat. Together with forest loss, prey depletion is one of the main threats to the survival of jaguars (Panthera onca) and pumas (Puma concolor) throughout the Neotropics. Generally, primates are not considered main prey for jaguar and puma, and their inclusion in the diet could be indicative of ongoing prey species decline. Here, we investigate the effect of habitat type and disturbance on primate predation by large cats. Surveys took place during the dry seasons (March to June) of 2010 and 2011, covering a total of 608.5 km across 24 localities in the Uxpanapa Valley, Mexico. We found 65 felid scat samples with the aid of a wildlife scat detection dog, and then examined them to identify predator species and classify the prey remains they contained. Primates represented the most frequent prey (35%) for both jaguar and puma in our study site and constituted approximately half of the biomass consumed by these felines in the area. Primate remains were more likely to be found in scats surrounded by the lowest percentage of conserved forest or in areas surrounded by more villages, showing the potential effects of human activities on these species' populations. The high proportion of primates found in scats within our study site could be an early indication that populations of ungulates and other “typical” prey are beginning to collapse, and urgent conservation interventions are needed for both large cats and primates before they become locally extinct. Abstract in Spanish is available with online material.     

Differential Use of Trails by Forest Mammals and the Implications for Camera-Trap Studies: A Case Study from Belize

Relative abundance indices are often used to compare species abundance between sites. The indices assume that species have similar detection probabilities, or that differences between detection probabilities are known and can be corrected for. Indices often consist of encounter frequencies of footprints, burrows, markings or photo captures along trails or transect lines, but the assumption of equal detection probabilities is rarely validated. This study analyzes detection probabilities of a range of Neotropical mammals on trails in dense secondary forests, using camera-trap and track data. Photo captures of the two large cats, jaguars ( Panthera onca ) and pumas ( Puma concolor ), were correlated solely with trail variables, while photo captures of their potential prey species had no correlation or negative correlation with trail variables. The Neotropical mammals varied greatly in their tendency to follow or cross trails based on footprints surveys. This indicates that camera locations on trails will have varying detection probability for these Neotropical mammals. Even the two similar-sized jaguars and pumas, occupying relatively similar niches, differed subtly in their use of trails. Pumas followed trails more completely while jaguars were more likely to deviate from trails. The ecological significance of these findings is that jaguars seem to be more willing to use the forest matrix away from trails than do pumas. We conclude that trail-based indices, such as photographic captures or tracks along trails, are not appropriate for comparison between Neotropical species, and not even between relatively similar species like jaguars and pumas.     

Neo-tropical felid activity patterns in relation to potential prey and intraguild competitors in the Calakmul Biosphere Reserve,Mexico

Predator behaviors influence, and are influenced by, prey and competitor behaviors. Jaguars (Panthera onca), pumas (Puma concolor), and ocelots (Leopardus pardalis) coexist throughout their geographic range as the three largest predators in a multi-predator community across diverse environments. This study tested for non-random segregation and overlap in the activity patterns of these felids and their shared prey in the southern buffer zone of the Calakmul Biosphere Reserve, in southern Mexico, using camera traps during February to August 2019. We detected little temporal segregation between the nocturnal activities of jaguars, pumas, and ocelots, although pumas were more active closer to dawn. Jaguars had low activity overlap with species likely to be common prey, whereas ocelots had high overlap with their potential prey. Pumas displayed finer-scale similarities in activity with species likely to be common prey. In an understudied area of conservation importance, this study shows that temporal segregation is an unlikely mechanism of coexistence. Further research should incorporate spatio-temporal avoidance and dietary differences to improve our understanding of the mechanisms that drive coexistence between generalist species in a diverse assemblage of threatened felids. Abstract in Spanish is available with online material.     

High Proportion of Male Faeces in Jaguar Populations

Faeces provide relevant biological information which includes, with the application of genetic techniques, the sex and identity of individuals that defecated, thus providing potentially useful data on the behaviour and ecology of individuals, as well as the dynamics and structure of populations. This paper presents estimates of the sex ratio of different felid species (jaguar, Panthera onca; puma, Puma concolor; and ocelot/margay, Leopardus pardalis/Leopardus wiedi) as observed in field collected faeces, and proposes several hypotheses that could explain the strikingly high proportion of faeces from male jaguars. The proportion of male and female faeces was estimated using a non-invasive faecal sampling method in 14 study areas in Mexico and Brazil. Faecal samples were genetically analysed to identify the species, the sex and the individual (the latter only for samples identified as belonging to jaguars). Considering the three species, 72.6% of faeces (n = 493) were from males; however, there were significant differences among them, with the proportion from males being higher for jaguars than for pumas and ocelots/margays. A male-bias was consistently observed in all study areas for jaguar faeces, but not for the other species. For jaguars the trend was the same when considering the number of individuals identified (n = 68), with an average of 4.2±0.56 faeces per male and 2.0±0.36 per female. The observed faecal marking patterns might be related to the behaviour of female jaguars directed toward protecting litters from males, and in both male and female pumas, to prevent interspecific aggressions from male jaguars. The hypothesis that there are effectively more males than females in jaguar populations cannot be discarded, which could be due to the fact that females are territorial and males are not, or a tendency for males to disperse into suboptimal areas for the species.     

Resource selection and its implications for wide-ranging mammals of the brazilian cerrado

Conserving animals beyond protected areas is critical because even the largest reserves may be too small to maintain viable populations for many wide-ranging species. Identification of landscape features that will promote persistence of a diverse array of species is a high priority, particularly, for protected areas that reside in regions of otherwise extensive habitat loss. This is the case for Emas National Park, a small but important protected area located in the Brazilian Cerrado, the world's most biologically diverse savanna. Emas Park is a large-mammal global conservation priority area but is too small to protect wide-ranging mammals for the long-term and conserving these populations will depend on the landscape surrounding the park. We employed novel, noninvasive methods to determine the relative importance of resources found within the park, as well as identify landscape features that promote persistence of wide-ranging mammals outside reserve borders. We used scat detection dogs to survey for five large mammals of conservation concern: giant armadillo (Priodontes maximus), giant anteater (Myrmecophaga tridactyla), maned wolf (Chrysocyon brachyurus), jaguar (Panthera onca), and puma (Puma concolor). We estimated resource selection probability functions for each species from 1,572 scat locations and 434 giant armadillo burrow locations. Results indicate that giant armadillos and jaguars are highly selective of natural habitats, which makes both species sensitive to landscape change from agricultural development. Due to the high amount of such development outside of the Emas Park boundary, the park provides rare resource conditions that are particularly important for these two species. We also reveal that both woodland and forest vegetation remnants enable use of the agricultural landscape as a whole for maned wolves, pumas, and giant anteaters. We identify those features and their landscape compositions that should be prioritized for conservation, arguing that a multi-faceted approach is required to protect these species.     

Phylogeography, population history and conservation genetics of jaguars (Panthera onca, Mammalia, Felidae)

The jaguar (Panthera onca), the largest felid in the American Continent, is currently threatened by habitat loss, fragmentation and human persecution. We have investigated the genetic diversity, population structure and demographic history of jaguars across their geographical range by analysing 715 base pairs of the mitochondrial DNA (mtDNA) control region and 29 microsatellite loci in approximately 40 individuals sampled from Mexico to southern Brazil. Jaguars display low to moderate levels of mtDNA diversity and medium to high levels of microsatellite size variation, and show evidence of a recent demographic expansion. We estimate that extant jaguar mtDNA lineages arose 280 000-510 000 years ago (95% CI 137 000-830 000 years ago), a younger date than suggested by available fossil data. No strong geographical structure was observed, in contrast to previously proposed subspecific partitions. However, major geographical barriers such as the Amazon river and the Darien straits between northern South America and Central America appear to have restricted historical gene flow in this species, producing measurable genetic differentiation. Jaguars could be divided into four incompletely isolated phylogeographic groups, and further sampling may reveal a finer pattern of subdivision or isolation by distance on a regional level. Operational conservation units for this species can be defined on a biome or ecosystem scale, but should take into account the historical barriers to dispersal identified here. Conservation strategies for jaguars should aim to maintain high levels of gene flow over broad geographical areas, possibly through active management of disconnected populations on a regional scale.     

Predation of wild spider monkeys at La Macarena,Colombia

The killing of an adult male spider monkey (Ateles belzebuth ) by a jaguar (Panthera onca) and a predation attempt by a puma (Felis concolor) on an adult female spider monkey have been observed at the CIEM (Centro de Investigaciones Ecológicas La Macarena), La Macarena, Colombia. These incidents occurred directly in front of an observer, even though it is said that predation under direct observation on any type of primate rarely occurs. On the basis of a review of the literature, and the observations reported here, we suggest that jaguars and pumas are likely to be the only significant potential predators on adult spider monkeys, probably because of their large body size.     

First Evidence of Canine Distemper in Brazilian Free-Ranging Felids

Serum samples from 19 jaguars (Panthera onca), nine pumas (Puma concolor), and two ocelots (Leopardus pardalis) were collected between January 1999 and March of 2005 and tested for presence of canine distemper virus (CDV). All cats were free-ranging animals living in two protected areas in the Brazilian Atlantic Forest. In addition, 111 domestic dogs from nearby areas were sampled for CDV. Our results show the first evidence of CDV exposure in Brazilian free-ranging felids. From the 30 samples analyzed, six jaguars and one puma were tested seropositive for CDV. All seropositive large felids were from Ivinhema State Park, resulting in 31.5% of the sampled jaguars or 60% of the total jaguar population in Ivinhema State Park, and 11.28% of the sampled pumas. From the total 111 domestic dogs sampled, 45 were tested seropositive for CDV. At Morro do Diabo State Park, 34.6% of the dogs sampled were positive for CDV, and 100% at Ivinhema State Park. Canine distemper virus in wild felids seems to be related with home range use and in close association with domestic dogs living in nearby areas.     

Cell population indexes of spermatogenic yield and testicular sperm reserves in adult jaguars (Panthera onca)

The intrinsic yield of spermatogenesis and supporting capacity of Sertoli cells are the desirable indicators of sperm production in a species. The objective of the present study was to quantify intrinsic yield and the Sertoli cell index in the spermatogenic process and estimate testicular sperm reserves by histological assessment of fragments obtained by testicular biopsy of five adult jaguars in captivity. The testicular fragments were fixed in 4% glutaric aldehyde, dehydrated at increasing alcohol concentrations, included into hydroxyethyl methacrylate, and were cut into 4 μm thickness. In the seminiferous epithelium of the jaguar, 9.2 primary spermatocytes in pre-leptotene were produced by “A” spermatogonia. During the meiotic divisions only 3.2 spermatids were produced by a primary spermatocyte. The general spermatogenic yield of the jaguar was about 23.4 cells and each Sertoli cell was able to maintain about 19.2 germ cells, 11 of them were round spermatids. In each seminiferous epithelium cycle about 166 million spermatozoa were produced by each gram of testicular tissue. In adult jaguars, the general spermatogenic yield was similar to the yield observed in pumas, greater than that observed for the domestic cat, but less compared to most domestic animals.