Cuauhtémoc Chávez

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.

Fine-Scale Habitat Segregation between Two Ecologically Similar Top Predators

Similar, coexisting species often segregate along the spatial ecological axis. Here, we examine if two top predators (jaguars and pumas) present different fine-scale habitat use in areas of coexistence, and discuss if the observed pattern can be explained by the risk of interference competition between them. Interference competition theory predicts that pumas should avoid habitats or areas used by jaguars (the dominant species), and as a consequence should present more variability of niche parameters across study areas. We used non-invasive genetic sampling of faeces in 12 different areas and sensor satellite fine-scale habitat indices to answer these questions. Meta-analysis confirmed differences in fine-scale habitat use between jaguars and pumas. Furthermore, average marginality of the realized niches of pumas was more variable than those of jaguars, and tolerance (a measure of niche breadth) was on average 2.2 times higher in pumas than in jaguars, as expected under the interference competition risk hypothesis. The use of sensor satellite fine-scale habitat indices allowed the detection of subtle differences in the environmental characteristics of the habitats used by these two similar top predators, which, as a rule, until now were recorded using the same general habitat types. The detection of fine spatial segregation between these two top predators was scale-dependent.

Genetic variability and structure of jaguar (Panthera onca) in Mexican zoos

Genealogical records of animals (studbook) are created to avoid reproduction between closely related individuals, which could cause inbreeding, particularly for such endangered species as the Panthera onca (Linnaeus, 1758). Jaguar is the largest felid in the Americas and is considered an important ecological key species. In Mexico, wild jaguar populations have been significantly reduced in recent decades, and population decline typically accompany decreases in genetic variation. There is no current census of captive jaguars in Mexico, and zoos do not follow a standardized protocol in breeding programs based on genetic studies. Here, we emphasise the importance of maintaining an adequate level of genetic variation and propose the implementation of standardised studbooks for jaguars in Mexico, mainly to avoid inbreeding. In addition, achieving the aims of studbook registration would provide a population genetic characterisation that could serve as a basis for ex situ conservation programmes.

Gene flow and genetic structure of the puma and jaguar in Mexico

Gene flow among populations and subpopulations homogenizes allele frequencies. This mechanism is strongly influenced by species dispersal ability, frequently correlating genetic variation with distance among individuals, which is also known as an isolation-by-distance pattern. Species with high dispersal abilities are expected to show a limited isolation-by-distance pattern compared to those with reduced dispersal. Here, we use non-invasive genetic sampling of faeces to evaluate how isolation-by-distance is differentially structured in jaguar and puma populations in Mexico. We have optimized and validated a reliable and standardized non-invasive genetic sampling protocol to monitor pumas based on 12 microsatellite markers, as well as applied a previously published and consistent protocol for jaguars. We found that jaguars and pumas were not uniform and panmictic populations. Spatial trends in allele frequencies for both species generated clinal patterns. However, pumas showed a stronger isolation-by-distance pattern than jaguars, which was expected since pumas seem to have a lower dispersal ability than jaguars. The genetic structures of both species differed at the level of subpopulations. These results reinforce the differences in intensity of isolation-by-distance between two generalist species with high dispersal ability.

Scraping marking behaviour of the largest Neotropical felids

Background Details of how, why and in what conditions large felids make scrapes is unknown. Here, we examined the general hypothesis about the use of scrapes for marking proposals, as well as to communicate with other individuals to signalize particular points or areas of interest, by studying scrape-marking behaviour of jaguars and pumas. Methods We surveyed by scrapes between five days and two months mainly during dry season in five study areas from Mexico (El Edén and San Ignacio), Belize (Cockscomb) and Brazil (Angatuba and Serra das Almas), which differed in presence and/or abundance of jaguars and pumas. Paths were slowly walked while searching for scrapes by teams normally composed of two people and tracks were stored in GPS, distinguishing the type of path surveyed (unpaved track roads, trails and cross-country). Results We found a total of 269 felid scrapes along 467 km of paths surveyed, obtaining a finding rate of 0.576 scrapes per km. Most scrapes were found in car tracks (0.629 scrapes per km), followed by trails (0.581 scrapes per km), and rarely did we find scrapes in cross country (0.094 scrapes per km). In trails, scrapes were found in a similar frequency in the centre and edge, whereas in car tracks they were mainly found in the edge. There were also clear differences in the position of the scrapes between study areas that differed in presence and/or abundance of pumas and jaguars, with scrapes located mainly in the centre in areas only with pumas, in the centre and in the edge in areas with a similar number of jaguars and pumas, and in the edge in area mainly dominated by jaguars. The remarking rate tended to be higher in one of the areas with only pumas where natural vegetation was scarcer. Felids chose sites mainly covered by leaves and located in paths less wide, clean and rarely used. Discussion Scraping was a frequent behaviour in the largest felids of America, although in some areas, scraping behaviour was rare. Scrapes seem to be signalizing some specific areas within territories and data suggest that they are made with the proposal of communication between individuals. It seems that a high scraping behaviour in pumas is not related to the presence of jaguars.

Range Expansion of a Locally Endangered Mustelid (Eira barbara) in Southern Mexico

Abstract. We documented the occurrence of Eira barbara in the municipalities of Tecpán de Galeana and Petatlán, state of Guerrero, Mexico. Our records represent a 450-km range expansion from the most recent northern occurrences of this species in the Mexican Pacific coast states.

Large Terrestrial Mammals

The Yucatan Peninsula contains some of the largest tracts of tropical forest in Mexico. These forests host six species of ungulates, including the largest and last survivor of the Neotropical megafauna, the Central American Tapir; one of the rarest ungulate species in Mexico, the White-lipped Peccary; and one endemic species of deer, the Gray Brocket. The Yucatan Peninsula is also home to another peccary species, two more deer species, five felid species, including the jaguar and the puma, and three species of primates. Most of these species face serious conservation threats, as their habitat is increasingly fragmented and because they are among the preferred targets of subsistence hunters. Some of these species require large areas of habitat in good conservation status to fulfill their basic needs for survival. Several research projects undertaken in the past years, and some currently being carried out, have addressed a lack of basic ecological information in this region. Among the ungulates, ecological research has focused on tapir, white-lipped peccary and the three deer species. For felids, scientific attention has been focused on the two largest species, the jaguar and puma; and all three primate species have received scientific attention recently, although more studies have focused on the black howler monkey. This chapter is an attempt to summarize what is currently known about these, the largest mammal species of the Yucatan Peninsula, and to point out gaps in the existing information. Such information is absolutely necessary to design conservation and management plans for these highly interesting and endangered species.