Lionesses, Panthera leoin the Serengeti ecosystem, Tanzania, assess the odds of winning group-territorial contests by counting the number of opponents they hear roaring. They will approach intruders aggressively only if they outnumber them. Here the lionesses in the Serengeti are compared with another population living nearby but in strikingly different ecological circumstances. The lions of Ng...

This study provides new data on chromosomal characteristics and DNA barcoding of three endemic loaches of Iran: spiny southern loach Cobitis linea (Heckel, 1847), Persian stream loach Oxynoemacheilus persa (Heckel, 1848) and Tongiorgi stream loach Oxynoemacheilus tongiorgii (Nalbant & Bianco, 1998). The chromosomes of these fishes were investigated by examining metaphase chromosome spreads obta...

Research on the allocation of resources to manage threatened species typically assumes that the state of the system is completely observable; for example whether a species is present or not. The majority of this research has converged on modeling problems as Markov decision processes (MDP), which give an optimal strategy driven by the current state of the system being managed. However, the pres...

Analysis of DNA sequence diversity at the 12S to 16S mitochondrial genes of 165 African lions (Panthera leo) from five main areas in Zambia has uncovered haplotypes which link Southern Africa with East Africa. Phylogenetic analysis suggests Zambia may serve as a bridge connecting the lion populations in southern Africa to eastern Africa, supporting earlier hypotheses that eastern-southern Afric...

Feces were collected from two female and one male Siberian tigers, Panthera tigris altaica. Steroid hormones were extracted from lyophilized feces and quantified by enzyme immunoassay. The fecal contents of estradiol-17beta (E(2)) and testosterone in the females and male, respectively, changed markedly throughout the year. The fecal E(2) contents of females Nos. 179 and 238 increased at 26.4 +/...

Perfluorinated compounds (PFCs) are used in a variety of industrial applications. We tested the hypothesis that, in Amur tigers (Panthera tigris altaica), captivity in industrialized areas increases PFC levels, potentially presenting a health risk to these animals. Serum samples were collected from 100 tigers from industrialized or nonindustrialized regions in China with nonpoint sources of PFC...

Background Large carnivores influence ecosystem functions at various scales. Thus, their local extinction is not only a species-specific conservation concern, but also reflects on the overall habitat quality and ecosystem value. Species-habitat relationships at fine scale reflect the individuals' ability to procure resources and negotiate intraspecific competition. Such fine scale habitat choic...