239 research outputs found

    Movement patterns and athletic performance of leopards in the Okavango Delta

    Get PDF
    Although leopards are the most widespread of all the big cats and are known for their adaptability, they are elusive and little is known in detail about their movement and hunting energetics. We used high-resolution GPS/IMU (inertial measurement unit) collars to record position, activity and the first high-speed movement data on four male leopards in the Okavango Delta, an area with high habitat diversity and habitat fragmentation. Leopards in this study were generally active and conducted more runs during the night, with peaks in activity and number of runs in the morning and evening twilight. Runs were generally short (less than 100 m) and relatively slow (maximum speed 5.3 m s−1, mean of individual medians) compared to other large predators. Average daily travel distance was 11 km and maximum daily travel distance was 29 km. No direct correlation was found between average daily temperature and travel distance or between season and travel distance. Total daily energy requirements based on locomotor cost and basal metabolic rate varied little between individuals and over time. This study provides novel insights into movement patterns and athletic performance of leopards through quantitative high-resolution measurement of the locomotor, energetic, spatial and temporal movement characteristics. The results are unbiased by methodological and observational limitations characteristic of previous studies and demonstrate the utility of applying new technologies to field studies of elusive nocturnal species

    Spatial ecology of jaguars, pumas, and ocelots: a review of the state of knowledge

    Get PDF
    Knowledge of the spatial ecology of mammalian carnivores is critical for understanding species’ biology and designing effective conservation and management interventions. We reviewed the available information about the spatial ecology of jaguars Panthera onca, pumas Puma concolor, and ocelots Leopardus pardalis, and we examined how sex and extrinsic variables affect their spatial behaviour. Sixty-one articles addressing home range, home range overlap, daily net displacement (straight-line distance between two locations on consecutive days), and/or distance of dispersal of the three species were included. Meta-analysis, ANOVA, ANCOVA, and beta regression tests were run to analyse differences among species and sexes and to elucidate the influence of other variables, such as latitude and ecoregion, on spatial behaviour. Pumas had on average larger home ranges (mean ± SE: 281.87 ± 35.76 km) than jaguars (128.61 ± 49.5 km) and ocelots (12.46 ± 3.39 km). Intersexual range overlap was higher than intrasexual range overlap in jaguars and pumas. Sex affected the home range size of all three species, but only influenced daily net displacement in ocelots. Ecoregion affected the home range size of all three species but did not significantly affect either the daily net displacement or the dispersal distance of pumas. Latitude affected the home range size of jaguars and pumas. It did not affect daily net displacement or dispersal distance in jaguars and pumas, but did affect daily net displacement in ocelots. Although there was a lack of studies in most countries for the three species, information was particularly lacking in the Neotropics for jaguars and pumas and in North America for ocelots. Researchers usually presented low sample sizes and used different methods to examine the ecological issues considered here. Homogenisation of methods is needed to clarify the ecology of these species and to allow a better understanding of the threats to their populations.Peer Reviewe

    Noninvasive genetic population survey of snow leopards (Panthera uncia) in Kangchenjunga conservation area, Shey Phoksundo National Park and surrounding buffer zones of Nepal

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The endangered snow leopard is found throughout major mountain ranges of Central Asia, including the remote Himalayas. However, because of their elusive behavior, sparse distribution, and poor access to their habitat, there is a lack of reliable information on their population status and demography, particularly in Nepal. Therefore, we utilized noninvasive genetic techniques to conduct a preliminary snow leopard survey in two protected areas of Nepal.</p> <p>Results</p> <p>A total of 71 putative snow leopard scats were collected and analyzed from two different areas; Shey Phoksundo National Park (SPNP) in the west and Kangchanjunga Conservation Area (KCA) in the east. Nineteen (27%) scats were genetically identified as snow leopards, and 10 (53%) of these were successfully genotyped at 6 microsatellite loci. Two samples showed identical genotype profiles indicating a total of 9 individual snow leopards. Four individual snow leopards were identified in SPNP (1 male and 3 females) and five (2 males and 3 females) in KCA.</p> <p>Conclusions</p> <p>We were able to confirm the occurrence of snow leopards in both study areas and determine the minimum number present. This information can be used to design more in-depth population surveys that will enable estimation of snow leopard population abundance at these sites.</p

    A 15.65 solar mass black hole in an eclipsing binary in the nearby spiral galaxy Messier 33

    Full text link
    Stellar-mass black holes are discovered in X-ray emitting binary systems, where their mass can be determined from the dynamics of their companion stars. Models of stellar evolution have difficulty producing black holes in close binaries with masses >10 solar masses, which is consistent with the fact that the most massive stellar black holes known so all have masses within 1 sigma of 10 solar masses. Here we report a mass of 15.65 +/- 1.45 solar masses for the black hole in the recently discovered system M33 X-7, which is located in the nearby galaxy Messier 33 (M33) and is the only known black hole that is in an eclipsing binary. In order to produce such a massive black hole, the progenitor star must have retained much of its outer envelope until after helium fusion in the core was completed. On the other hand, in order for the black hole to be in its present 3.45 day orbit about its 70.0 +/- 6.9 solar mass companion, there must have been a ``common envelope'' phase of evolution in which a significant amount of mass was lost from the system. We find the common envelope phase could not have occured in M33 X-7 unless the amount of mass lost from the progenitor during its evolution was an order of magnitude less than what is usually assumed in evolutionary models of massive stars.Comment: To appear in Nature October 18, 2007. Four figures (one color figure degraded). Differs slightly from published version. Supplementary Information follows in a separate postin

    Bekkenbanden voor acute stabilisatie van instabiele bekkenfracturen

    Get PDF
    Bekkenbanden zijn ontwikkeld voor de acute behandeling van instabiele bekkenringfracturen in de prehospitale fase. Deze behandeling is gericht op het beperken van het inwendig bloedverlies door het verkleinen van het bij bekkenfracturen toegenomen bekkenvolume en het stabiliseren van de fractuurdelen. Het effect van commercieel verkrijgbare bekkenbanden op de reductie van de symphysis pubisdiastase en de hemodynamische stabiliteit is aangetoond. Het langdurig gebruik van bekkenbanden wordt ontraden wegens toegenomen risico op het ontwikkelen van decubitus. Met name langdurige immobilisatie met een bekkenband op een traumaplank dient voorkomen te worden. In dit artikel wordt een aantal verschillende bekkenbanden besproken en wordt een casus gepresenteerd.Pelvic circumferential compression devices have been developed for initial treatment of unstable pelvic ring fractures in the prehospital situation. The treatment is aimed at achieving tamponade by reducing the increased pelvic volume and reducing the bleeding from fracture surfaces. The effect of commercially available pelvic circumferential compression devices on the reduction of symphysis pubis diastasis and the resuscitation has been proved. Prolonged use of these devices is complicated by the risk of development of pressure sores. Therefore prolonged immobilization on a spine board should be avoided. A number of different pelvic binders will be discussed in this article, which also presents a case

    Long-Term Monitoring of Fecal Steroid Hormones in Female Snow Leopards (Panthera uncia) during Pregnancy or Pseudopregnancy

    Get PDF
    Knowledge of the basic reproductive physiology of snow leopards is required urgently in order to develop a suitable management conditions under captivity. In this study, the long-term monitoring of concentrations of three steroid hormones in fecal matter of three female snow leopards was performed using enzyme immunoassays: (1) estradiol-17β, (2) progesterone and (3) cortisol metabolite. Two of the female animals were housed with a male during the winter breeding season, and copulated around the day the estradiol-17β metabolite peaked subsequently becoming pregnant. The other female was treated in two different ways: (1) first housed with a male in all year round and then (2) in the winter season only. She did not mate with him on the first occasion, but did so latter around when estradiol-17β metabolite peaked, and became pseudopregnant. During pregnancy, progesterone metabolite concentrations increased for 92 or 94 days, with this period being approximately twice as long as in the pseudopregnant case (31, 42, 49 and 53 days). The levels of cortisol metabolite in the pseudopregnant female (1.35 µg/g) were significantly higher than in the pregnant females (0.33 and 0.24 µg/g) (P<0.05). Similarly, during the breeding season, the levels of estradiol-17β metabolite in the pseudopregnant female (2.18 µg/g) were significantly higher than those in the pregnant females (0.81 and 0.85 µg/g) (P<0.05). Unlike cortisol the average levels of estradiol-17β during the breeding season were independent of reproductive success

    Cheetah mothers' vigilance: looking out for prey or for predators?

    Full text link
    Free-living cheetah ( Acinonyx jubatus ) cubs are killed by a number of predators, thus vigilance in cheetah mothers may be a form of anti-predator behaviour as well as a means of locating prey. Mothers' vigilance during the day was closely associated with measures of hunting but not with measures of anti-predator behaviour. In contrast, mothers' vigilance at kills was not related to hunting but was related to anti-predator behaviour. Both forms of vigilance decreased as cubs grew older. Vigilance during the day increased with litter size which supports a model of ‘shared’ parental investment (Lazarus and Inglis 1986) because after prey had been located and caught by mothers, cubs shared the prey between them. Vigilance at kills did not increase with litter size when cubs were young; in these situations predators stole cheetahs' prey and rarely chased cubs so, at most, only a single cub would be taken. Mothers' anti-predator behaviour away from kills did increase with litter size at young cub ages however; more cubs are killed in these circumstances the greater is the size of the litter. When cubs were older and could outrun predators, neither vigilance at kills nor anti-predator behaviour increased with litter size. These results strongly support two models of ‘unshared’ investment (Lazarus and Inglis 1986) and demonstrate, not only that superficially similar behaviour has different functions in different contexts, but that parental investment is shaped by the type of benefits accrued from it.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46879/1/265_2004_Article_BF00300681.pd

    Spatial Guilds in the Serengeti Food Web Revealed by a Bayesian Group Model

    Get PDF
    Food webs, networks of feeding relationships among organisms, provide fundamental insights into mechanisms that determine ecosystem stability and persistence. Despite long-standing interest in the compartmental structure of food webs, past network analyses of food webs have been constrained by a standard definition of compartments, or modules, that requires many links within compartments and few links between them. Empirical analyses have been further limited by low-resolution data for primary producers. In this paper, we present a Bayesian computational method for identifying group structure in food webs using a flexible definition of a group that can describe both functional roles and standard compartments. The Serengeti ecosystem provides an opportunity to examine structure in a newly compiled food web that includes species-level resolution among plants, allowing us to address whether groups in the food web correspond to tightly-connected compartments or functional groups, and whether network structure reflects spatial or trophic organization, or a combination of the two. We have compiled the major mammalian and plant components of the Serengeti food web from published literature, and we infer its group structure using our method. We find that network structure corresponds to spatially distinct plant groups coupled at higher trophic levels by groups of herbivores, which are in turn coupled by carnivore groups. Thus the group structure of the Serengeti web represents a mixture of trophic guild structure and spatial patterns, in contrast to the standard compartments typically identified in ecological networks. From data consisting only of nodes and links, the group structure that emerges supports recent ideas on spatial coupling and energy channels in ecosystems that have been proposed as important for persistence.Comment: 28 pages, 6 figures (+ 3 supporting), 2 tables (+ 4 supporting

    Hypernovae and Other Black-Hole-Forming Supernovae

    Full text link
    During the last few years, a number of exceptional core-collapse supernovae (SNe) have been discovered. Their kinetic energy of the explosions are larger by more than an order of magnitude than the typical values for this type of SNe, so that these SNe have been called `Hypernovae'. We first describe how the basic properties of hypernovae can be derived from observations and modeling. These hypernovae seem to come from rather massive stars, thus forming black holes. On the other hand, there are some examples of massive SNe with only a small kinetic energy. We suggest that stars with non-rotating black holes are likely to collapse "quietly" ejecting a small amount of heavy elements (Faint supernovae). In contrast, stars with rotating black holes are likely to give rise to very energetic supernovae (Hypernovae). We present distinct nucleosynthesis features of these two types of "black-hole-forming" supernovae. Hypernova nucleosynthesis is characterized by larger abundance ratios (Zn,Co,V,Ti)/Fe and smaller (Mn,Cr)/Fe. Nucleosynthesis in Faint supernovae is characterized by a large amount of fall-back. We show that the abundance pattern of the most Fe deficient star, HE0107-5240, and other extremely metal-poor carbon-rich stars are in good accord with those of black-hole-forming supernovae, but not pair-instability supernovae. This suggests that black-hole-forming supernovae made important contributions to the early Galactic (and cosmic) chemical evolution.Comment: 49 pages, to be published in "Stellar Collapse" (Astrophysics and Space Science; Kluwer) ed. C. L. Fryer (2003
    • …
    corecore