419 research outputs found

    Über die stammesgeschichtliche Herkunft menschlicher Antriebs- und Verhaltensweisen

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    Es ist mir eine große Freude, heute abend hier - sozusagen als Schlußlicht Ihrer Vortragsreihe - ein wenig über die Möglichkeiten der Verhaltensforschung am Menschen zu plaudern. Ich weiß, daß in den letzten Jahren infolge einer Reihe von mehr oder weniger populären, zum Teil weit bekannt gewordenen Büchern in der Offentlichkeit ein etwas schiefes Bild entstanden ist vom Ehrgeiz der Verhaltensforscher, derart, daß die jetzt eigentlich alles alleine machen möchten nach dem Schema: "Hoppla, jetzt komm ich, und alles das, was vorher war, werfen wir jetzt auf den Müllhaufen." Was wir jedoch wirklich behaupten und auch - glaube ich - recht gut nachweisen können, ist folgendes: Neue Methoden, neue Möglichkeiten der Forschung bringen Dinge ans Tageslicht, die bisher und mit den Methoden der anderen Disziplinen, die sich mit der Forschung am Menschen und am menschlichen Verhalten befassen, nicht oder nicht so gut faßbar waren und sind. Wir erweitern so ein wenig den Horizont dessen, was faßbar wird

    New principle for large-scale preparation of purified human pancreas islets

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    Because successful human islet transplantation requires large quantities of viable islets that must be separated from the highly immunogenic exocrine tissue and because handpicking is too time-consuming and laborious to be clinically relevant, a new approach for solving this problem has been established in rat models. It is based on the principle that magnetic microspheres (MMSs) coupled to lectins with binding specificity for the exocrine tissue portion are trapped in an electromagnetic field, thus providing effluent islets of a high degree of purity. In this study our aim was to adapt this princip'le to human islet preparations. In this context our prime interest was focused on a lectin suitable for human pancreatic tissue. Of 19 different lectins tested, only 1, Wisteria floribunda agglutinin (WFA), is suitable, as shown by immunofluorescence, MMS-Iectin binding, and magnetic separatio

    The scaling of postcranial muscles in cats (Felidae) I: forelimb, cervical, and thoracic muscles

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    The body masses of cats (Mammalia, Carnivora, Felidae) span a ~300‐fold range from the smallest to largest species. Despite this range, felid musculoskeletal anatomy remains remarkably conservative, including the maintenance of a crouched limb posture at unusually large sizes. The forelimbs in felids are important for body support and other aspects of locomotion, as well as climbing and prey capture, with the assistance of the vertebral (and hindlimb) muscles. Here, we examine the scaling of the anterior postcranial musculature across felids to assess scaling patterns between different species spanning the range of felid body sizes. The muscle architecture (lengths and masses of the muscle‐tendon unit components) for the forelimb, cervical and thoracic muscles was quantified to analyse how the muscles scale with body mass. Our results demonstrate that physiological cross‐sectional areas of the forelimb muscles scale positively with increasing body mass (i.e. becoming relatively larger). Many significantly allometric variables pertain to shoulder support, whereas the rest of the limb muscles become relatively weaker in larger felid species. However, when phylogenetic relationships were corrected for, most of these significant relationships disappeared, leaving no significantly allometric muscle metrics. The majority of cervical and thoracic muscle metrics are not significantly allometric, despite there being many allometric skeletal elements in these regions. When forelimb muscle data were considered in isolation or in combination with those of the vertebral muscles in principal components analyses and MANOVAs, there was no significant discrimination among species by either size or locomotory mode. Our results support the inference that larger felid species have relatively weaker anterior postcranial musculature compared with smaller species, due to an absence of significant positive allometry of forelimb or vertebral muscle architecture. This difference in strength is consistent with behavioural changes in larger felids, such as a reduction of maximal speed and other aspects of locomotor abilities

    DNA ladders can be used to size polyphosphate resolved by polyacrylamide gel electrophoresis

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    PAGE is often used to resolve inorganic polyphosphates (polyP), but unfortunately polyP size ladders are not commercially available. Since several dyes that are commonly used to detect nucleic acids in gels also stain polyP, we examined the utility of commercially available DNA size ladders for estimating polyP polymer lengths by gel electrophoresis. Narrow size fractions of polyP were prepared and their polymer lengths were quantified using NMR. Commercially available DNA ladders and these polyP fractions were then subjected to PAGE to determine the relationship between migration of DNA vs polyP, which was found to be: log10(dsDNA length in bp) = 1.66 × log10(polyP length in phosphate units) − 1.97. This relationship between DNA and polyP size held for a variety of different polyacrylamide concentrations, indicating that DNA size ladders can readily be employed to estimate polyP polymer lengths by PAGE.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146466/1/elps6690_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146466/2/elps6690.pd

    Cryptic complexity in felid vertebral evolution: shape differentiation and allometry of the axial skeleton

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    Members of the mammalian family Felidae (extant and extinct cats) are grossly phenotypically similar, but display a 300-fold range in body size, from less than 1 kg to more than 300 kg. In addition to differences in body mass, felid species show dietary and locomotory specializations that correlate to skull and limb osteological measurements, such as shape or cross-sectional area. However, ecological correlates to the axial skeleton are yet untested. Here, we build on previous studies of the biomechanical and morphological evolution of the felid appendicular skeleton by conducting a quantitative analysis of morphology and allometry in the presacral vertebral column across extant cats. Our results demonstrate that vertebral columns of arboreal, scansorial and terrestrial felids significantly differ in morphology, specifically in the lumbar region, while no distinction based on dietary specialization was found. Body size significantly influences vertebral morphology, with clear regionalization of allometry along the vertebral column, suggesting that anterior (cervicals and thoracics) and posterior (lumbar) vertebrae may be independently subjected to distinct selection pressures

    TNR and conservation on a university campus: a political ecological perspective

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    How to manage the impact of free-ranging cats on native wildlife is a polarizing issue. Conservation biologists largely support domestic cat euthanasia to mitigate impacts of free-ranging cat predation on small animal populations. Above all else, animal welfare activists support the humane treatment of free-ranging cats, objecting to euthanasia. Clearly, this issue of how to control free-ranging cat predation on small animals is value laden, and both positions must be considered and comprehended to promote effective conservation. Here, two gaps in the free-ranging cat—small-animal conservation literature are addressed. First, the importance of understanding the processes of domestication and evolution and how each relates to felid behavioral ecology is discussed. The leading hypothesis to explain domestication of wildcats (Felis silvestris) relates to their behavioral ecology as a solitary predator, which made them suited for pest control in early agricultural villages of the Old World. The relationship humans once had with cats, however, has changed because today domesticated cats are usually household pets. As a result, concerns of conservation biologists may relate to cats as predators, but cat welfare proponents come from the position of assuming responsibility for free-ranging household pets (and their feral offspring). Thus, the perceptions of pet owners and other members of the general public provide an important context that frames the relationship between free-ranging cats and small animal conservation. The second part of this paper assesses the effects of an information-based conservation approach on shifting student’s perception of a local Trap–Neuter–Return (TNR) program in introductory core science classes at the University of North Texas (UNT). UNT students are (knowingly or unknowingly) regularly in close proximity to a TNR program on campus that supports cat houses and feeding stations. A survey design implementing a tailored-information approach was used to communicate what TNR programs are, their goals, and the “conservationist” view of TNR programs. We gauged favorability of student responses to the goals of TNR programs prior to and after exposure to tailored information on conservation concerns related to free-ranging cats. Although these results are from a preliminary study, we suggest that an information-based approach may only be marginally effective at shifting perceptions about the conservation implications of free-ranging cats. Our position is that small animal conservation in Western societies occurs in the context of pet ownership, thus broader approaches that promote ecological understanding via environmental education are more likely to be successful than information-based approaches

    Development of a microfluidic SNP assay for lineage discrimination in the endangered hazel dormouse

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    Abstract The application of Genotyping-by-Sequencing (GBS) approaches is often restricted in wildlife monitoring and conservation genetics, as those fields often rely on noninvasively collected samples with low DNA content. Here we selected a subset of informative single-nucleotide polymorphisms (SNPs) from genome-wide data for lineage discrimination of a locally endangered Eurasian rodent, the hazel dormouse (Muscardinus avellanarius), and designed a microfluidic 96 SNP genotyping assay suitable for noninvasively collected samples. Analyses of 43 samples from different European countries confirmed successful discrimination of the Eastern and Western lineage and local substructure within those lineages, proving the suitability of the developed panel for identifying evolutionary significant units and conservation units. Application with 94 hair and scat samples collected in a recent monitoring study on the hazel dormouse in Southern Germany resulted in >99.5% amplification success showing the applicability of the new tool in genetic wildlife monitoring and conservation studies

    Intact carcasses as enrichment for large felids: Effects on on- and off-exhibit behaviors

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    Reducing stereotypic behaviors in captive animals is a goal for zoological institutions worldwide, and environmental enrichment is one tool commonly used to meet that end. Behavioral needs associated with feeding, however, are often neglected in large carnivores. To address these needs, I tested the effects of calf carcasses as enrichment for large felids. Over 14 weeks, I provided nine animals with up to seven intact carcasses. The cats were housed at Toledo Zoo, Potawatomi Zoo, and Binder Park Zoo. Animals were observed off and on exhibit for changes in feeding, natural, stereotypic, active, and inactive behaviors. I compared treatment behaviors with behaviors observed during a baseline period in which the animals were fed traditional processed diets. For these nine cats, carcass provision decreased off-exhibit stereotypic behaviors but had little impact on on-exhibit behaviors. Zoo Biol 21:37–47, 2002. © 2002 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34915/1/10033_ftp.pd

    Evolution of Skull and Mandible Shape in Cats (Carnivora: Felidae)

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    The felid family consists of two major subgroups, the sabretoothed and the feline cats, to which all extant species belong, and are the most anatomically derived of all carnivores for predation on large prey with a precision killing bite. There has been much controversy and uncertainty about why the skulls and mandibles of sabretoothed and feline cats evolved to become so anatomically divergent, but previous models have focused on single characters and no unifying hypothesis of evolutionary shape changes has been formulated. Here I show that the shape of the skull and mandible in derived sabrecats occupy entirely different positions within overall morphospace from feline cats, and that the evolution of skull and mandible shape has followed very different paths in the two subgroups. When normalised for body-size differences, evolution of bite forces differ markedly in the two groups, and are much lower in derived sabrecats, and they show a significant relationship with size and cranial shape, whereas no such relationship is present in feline cats. Evolution of skull and mandible shape in modern cats has been governed by the need for uniform powerful biting irrespective of body size, whereas in sabrecats, shape evolution was governed by selective pressures for efficient predation with hypertrophied upper canines at high gape angles, and bite forces were secondary and became progressively weaker during sabrecat evolution. The current study emphasises combinations of new techniques for morphological shape analysis and biomechanical studies to formulate evolutionary hypotheses for difficult groups

    Consistency of Leadership in Shoals of Mosquitofish (Gambusia holbrooki) in Novel and in Familiar Environments

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    In social animal groups, an individual's spatial position is a major determinant of both predation risk and foraging rewards. Additionally, the occupation of positions in the front of moving groups is generally assumed to correlate with the initiation of group movements. However, whether some individuals are predisposed to consistently occupy certain positions and, in some instances, to consistently lead groups over time is as yet unresolved in many species. Using the mosquitofish (Gambusia holbrooki), we examined the consistency of individuals' spatial positions within a moving group over successive trials. We found that certain individuals consistently occupied front positions in moving groups and also that it was typically these individuals that initiated group decisions. The number of individuals involved in leading the group varied according to the amount of information held by group members, with a greater number of changes in leadership in a novel compared to a relatively familiar environment. Finally, our results show that the occupation of lead positions in moving groups was not explained by characteristics such as dominance, size or sex, suggesting that certain individuals are predisposed to leadership roles. This suggests that being a leader or a follower may to some extent be an intrinsic property of the individual
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