| Records |
| Author |
Cameron, E.Z. |
Title  |
Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism |
Type |
Journal Article |
| Year |
2004 |
Publication |
Proceedings. Biological sciences / The Royal Society |
Abbreviated Journal |
Proc Biol Sci |
| Volume |
271 |
Issue |
1549 |
Pages |
1723-1728 |
| Keywords |
Age Factors; Animals; Body Constitution; *Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/*physiology; *Models, Biological; Reproduction/physiology; Seasons; Sex Factors; *Sex Ratio; Time Factors |
| Abstract |
Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios. |
| Address |
Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za |
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English |
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0962-8452 |
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PMID:15306293 |
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no |
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refbase @ user @ |
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413 |
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| Author |
Swanson, J.C. |
| Title |
Farm animal well-being and intensive production systems |
Type |
Journal Article |
| Year |
1995 |
Publication |
Journal of Animal Science |
Abbreviated Journal |
J. Anim Sci. |
| Volume |
73 |
Issue |
9 |
Pages |
2744-2751 |
| Keywords |
Animal Husbandry/legislation & jurisprudence/*standards; Animal Rights/legislation & jurisprudence/standards; Animal Welfare/legislation & jurisprudence/*standards; Animals; Animals, Domestic/*growth & development/*physiology; Breeding/legislation & jurisprudence/*standards; Cattle; Chickens; Environment; Reproduction/physiology; Sheep; Swine |
| Abstract |
Animal welfare, or well-being, is a social issue with ethical, scientific, political, and aesthetic properties. Answering questions about the welfare of animals requires scientific definition, assessment, solutions, and public acceptance. With respect to the actual well-being of the animal, most issues are centered on how the animal “feels” when managed within a specific level of confinement, during special agricultural practices (e.g., tail docking, beak trimming, etc.) and handling. Questions of this nature may require exploration of animal cognition, motivation, perception, and emotional states in addition to more commonly recognized indicators of well-being. Several general approaches have emerged for solving problems concerning animal well-being in intensive production systems: environmental, genetic, and therapeutic. Environmental approaches involve modifying existing systems to accommodate specific welfare concerns or development of alternative systems. Genetic approaches involve changing the behavioral and (or) physiological nature of the animal to reduce or eliminate behaviors that are undesirable within intensive system. Therapeutic approaches of a physical (tail docking, beak trimming) and physiological (drug and nutritional therapy) nature bring both concern and promise with regard to the reduction of confinement stress. Finally, the recent focus on commodity quality assurance programs may indirectly provide benefits for animal well-being. Although research in the area of animal well-being will provide important information for better animal management, handling, care, and the physical design of intensive production systems there is still some uncertainty regarding public acceptance. The aesthetics of modern intensive production systems may have as much to do with public acceptance as with science. |
| Address |
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506, USA |
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0021-8812 |
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| Notes |
PMID:8582867 |
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no |
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Equine Behaviour @ team @ |
Serial |
2752 |
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| Author |
Kaseda, Y.; Khalil, A.M. |
| Title |
Harem size and reproductive success of stallions in Misaki feral horses |
Type |
Journal Article |
| Year |
1996 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
| Volume |
47 |
Issue |
3-4 |
Pages |
163-173 |
| Keywords |
Harem size; Horse social organization; Reproduction; Blood types; Misaki feral horse |
| Abstract |
Over a 16-year period (1979-1994), long-term investigations were carried out on 14 Misaki feral stallions to analyze changes in harem size and the reproductive success. Harem size changed with the age of the stallions. Most stallions formed harem groups with four to five mares at the age of 4-6 and then the number of mares increased rapidly to the maximum at the age of 6-9 years. Thereafter, harem size decreased gradually to a minimum with advancing age. The harem size of 60 stable harem groups ranged from 1 to 9, and the average varied from a minimum mean of 1.8 in 1988 to a maximum mean of 5.3 in 1982. Mean harem size increased as adult sex ratio increased and a significant and positive correlation was found between them. One hundred and ninety-eight sire-foal pairs were determined by a paternity test with blood types and consort relations between stallions and mares during the study period. Out of 99 foals which were born in the stable harem groups, the true sires of 84 foals (85%) were the harem stallions in which the foals were born but the remaining 15 foals (15%) were sired by other harem stallions. Two out of three stallions which were studied throughout their lifetime produced 24 and 25 foals in 10 and 11 years of their reproductive lifespan, respectively. Another one produced only five foals in 6 years. The number of foals sired by the harem stallions was less than two over harem size 7 and some of the foals born in the harem were sired by other harem stallions. These results suggest that if a particular stallion monopolizes too many mares, he could not sire so many offspring because he could not always prevent his rival stallions from mating with his mares in wild or feral circumstances. |
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no |
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Equine Behaviour @ team @ |
Serial |
2308 |
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| Author |
Nelson, W.A.; Keirans, J.E.; Bell, J.F.; Clifford, C.M. |
| Title |
Host-ectoparasite relationships |
Type |
Journal Article |
| Year |
1975 |
Publication |
Journal of Medical Entomology |
Abbreviated Journal |
J Med Entomol |
| Volume |
12 |
Issue |
2 |
Pages |
143-166 |
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Animal Nutrition Physiology; Animals; Anoplura/physiology; *Arthropods; Birds/parasitology; Chickens/parasitology; Dermacentor/parasitology; Diptera; Ecology; Feeding Behavior; Female; Horses/parasitology; Humans; Male; Mallophaga/physiology; Mice/parasitology; Mites/physiology; Reproduction; Sarcoptes scabiei/physiology; Sheep/parasitology; Skin/parasitology; Ticks/physiology; Toxins, Biological/toxicity; Trombiculidae/physiology |
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0022-2585 |
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| Notes |
PMID:808617 |
Approved |
no |
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Equine Behaviour @ team @ |
Serial |
2704 |
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| Author |
Mech L.D. |
| Title |
Leadership in Wolf, Canis lupus, Packs. |
Type |
Journal Article |
| Year |
2000 |
Publication |
Canadian Field-Naturalist |
Abbreviated Journal |
Can Field Nat |
| Volume |
114 |
Issue |
2 |
Pages |
259-263 |
| Keywords |
Wolf, Canis lupus, leadership, behavior, foraging, movements, pup care, provisioning, sociality, reproduction, breeding, Northwest Territories. |
| Abstract |
I examine leadership in Wolf (Canis lupus) packs based on published observations and data gathered during summers from 1986 to 1998 studying a free-ranging pack of Wolves on Ellesmere Island that were habituated to my presence. The breeding male tended to initiate activities associated with foraging and travel, and the breeding female to initiate, and predominate in, pup care and protection. However, there was considerable overlap and interaction during these activities such that leadership could be considered a joint function. In packs with multiple breeders, quantitative information about leadership is needed. |
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no |
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Equine Behaviour @ team @ |
Serial |
4688 |
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| Author |
Wolf, M.; van Doorn, G.S.; Leimar, O.; Weissing, F.J. |
| Title |
Life-history trade-offs favour the evolution of animal personalities |
Type |
Journal Article |
| Year |
2007 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
447 |
Issue |
7144 |
Pages |
581-584 |
| Keywords |
Aggression/physiology/psychology; Animals; Behavior, Animal/*physiology; *Evolution; Exploratory Behavior/physiology; Models, Biological; Personality/*physiology; Predatory Behavior/physiology; Reproduction/physiology; Risk-Taking; Selection (Genetics) |
| Abstract |
In recent years evidence has been accumulating that personalities are not only found in humans but also in a wide range of other animal species. Individuals differ consistently in their behavioural tendencies and the behaviour in one context is correlated with the behaviour in multiple other contexts. From an adaptive perspective, the evolution of animal personalities is still a mystery, because a more flexible structure of behaviour should provide a selective advantage. Accordingly, many researchers view personalities as resulting from constraints imposed by the architecture of behaviour (but see ref. 12). In contrast, we show here that animal personalities can be given an adaptive explanation. Our argument is based on the insight that the trade-off between current and future reproduction often results in polymorphic populations in which some individuals put more emphasis on future fitness returns than others. Life-history theory predicts that such differences in fitness expectations should result in systematic differences in risk-taking behaviour. Individuals with high future expectations (who have much to lose) should be more risk-averse than individuals with low expectations. This applies to all kinds of risky situations, so individuals should consistently differ in their behaviour. By means of an evolutionary model we demonstrate that this basic principle results in the evolution of animal personalities. It simultaneously explains the coexistence of behavioural types, the consistency of behaviour through time and the structure of behavioural correlations across contexts. Moreover, it explains the common finding that explorative behaviour and risk-related traits like boldness and aggressiveness are common characteristics of animal personalities. |
| Address |
Theoretical Biology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands |
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English |
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1476-4687 |
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| Notes |
PMID:17538618 |
Approved |
no |
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Equine Behaviour @ team @ |
Serial |
4098 |
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Ganswindt, A.; Palme, R.; Heistermann, M.; Borragan, S.; Hodges, J.K. |
| Title |
Non-invasive assessment of adrenocortical function in the male African elephant (Loxodonta africana) and its relation to musth |
Type |
Journal Article |
| Year |
2003 |
Publication |
General and Comparative Endocrinology |
Abbreviated Journal |
Gen Comp Endocrinol |
| Volume |
134 |
Issue |
2 |
Pages |
156-166 |
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Adrenal Cortex/*metabolism/secretion; Adrenal Cortex Function Tests/methods/*veterinary; Adrenocorticotropic Hormone/physiology; Animals; Carbon Isotopes/diagnostic use; Chromatography, High Pressure Liquid/veterinary; Elephants/*metabolism/urine; Feces/*chemistry; Glucocorticoids/analysis/urine; Hydrocortisone/*analysis/diagnostic use/urine; Immunoenzyme Techniques/methods/veterinary; Male; Reproduction/physiology; Sexual Behavior, Animal/physiology; Stress, Psychological/diagnosis/*physiopathology; Testosterone/*analysis/diagnostic use/urine |
| Abstract |
Adult male elephants periodically show the phenomenon of musth, a condition associated with increased aggressiveness, restlessness, significant weight reduction and markedly elevated androgen levels. It has been suggested that musth-related behaviours are costly and that therefore musth may represent a form of physiological stress. In order to provide data on this largely unanswered question, the first aim of this study was to evaluate different assays for non-invasive assessment of adrenocortical function in the male African elephant by (i) characterizing the metabolism and excretion of [3H]cortisol (3H-C) and [14C]testosterone (14C-T) and (ii) using this information to evaluate the specificity of four antibodies for determination of excreted cortisol metabolites, particularly with respect to possible cross-reactions with androgen metabolites, and to assess their biological validity using an ACTH challenge test. Based on the methodology established, the second objective was to provide data on fecal cortisol metabolite concentrations in bulls during the musth and non-musth condition. 3H-C (1 mCi) and 14C-T (100 microCi) were injected simultaneously into a 16 year old male and all urine and feces collected for 30 and 86 h, respectively. The majority (82%) of cortisol metabolites was excreted into the urine, whereas testosterone metabolites were mainly (57%) excreted into the feces. Almost all radioactive metabolites recovered from urine were conjugated (86% 3H-C and 97% 14C-T). In contrast, 86% and >99% of the 3H-C and 14C-T metabolites recovered from feces consisted of unconjugated forms. HPLC separations indicated the presence of various metabolites of cortisol in both urine and feces, with cortisol being abundant in hydrolysed urine, but virtually absent in feces. Although all antibodies measured substantial amounts of immunoreactivity after HPLC separation of peak radioactive samples and detected an increase in glucocorticoid output following the ACTH challenge, only two (in feces against 3alpha,11-oxo-cortisol metabolites, measured by an 11-oxo-etiocholanolone-EIA and in urine against cortisol, measured by a cortisol-EIA) did not show substantial cross-reactivity with excreted 14C-T metabolites and could provide an acceptable degree of specificity for reliable assessment of glucocorticoid output from urine and feces. Based on these findings, concentrations of immunoreactive 3alpha,11-oxo-cortisol metabolites were determined in weekly fecal samples collected from four adult bulls over periods of 11-20 months to examine whether musth is associated with increased adrenal activity. Results showed that in each male levels of these cortisol metabolites were not elevated during periods of musth, suggesting that in the African elephant musth is generally not associated with marked elevations in glucocorticoid output. Given the complex nature of musth and the variety of factors that are likely to influence its manifestation, it is clear, however, that further studies, particularly on free-ranging animals, are needed before a possible relationship between musth and adrenal function can be resolved. This study also clearly illustrates the potential problems associated with cross-reacting metabolites of gonadal steroids in EIAs measuring glucocorticoid metabolites. This has to be taken into account when selecting assays and interpreting results of glucocorticoid metabolite analysis, not only for studies in the elephant but also in other species. |
| Address |
German Primate Centre, Department of Reproductive Biology, Kellnerweg 4, 37077 Gottingen, Germany. ganswindt@www.dpz.gdwg.de |
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0016-6480 |
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| Notes |
PMID:14511986 |
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no |
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Equine Behaviour @ team @ |
Serial |
4085 |
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| Author |
Collery, L. |
| Title |
Observations of equine animals under farm and feral conditions |
Type |
Journal Article |
| Year |
1974 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
| Volume |
6 |
Issue |
4 |
Pages |
170-173 |
| Keywords |
Aggression; Animals; Animals, Newborn; Breeding; Circadian Rhythm; Feeding Behavior; Female; Horses/*physiology; Housing, Animal; Humans; Male; Pregnancy; Puberty; Reproduction; Sexual Behavior, Animal; Social Dominance |
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0425-1644 |
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PMID:4473340 |
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refbase @ user @ |
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680 |
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Kampmann, S.; Hampson, B.A.; Pollitt, C.C. |
| Title |
Population dynamics of feral horses (Equus caballus) following above-average rainfall in a semi-arid environment of Australia |
Type |
Journal Article |
| Year |
2013 |
Publication |
Australian Veterinary Journal |
Abbreviated Journal |
Aust Vet J |
| Volume |
91 |
Issue |
11 |
Pages |
482-487 |
| Keywords |
animal welfare; ecology; horses; reproduction; wildlife |
| Abstract |
Background Recent record rainfall in much of semi-arid Central Australia is the most likely reason for a feral horse population increase in excess of normal. Uncontrolled numbers of feral horses have habitat degradation and animal welfare implications. Objectives The aims of this study were to investigate the social structure of feral horses and assess their population growth rate following unseasonably high rainfall. Methods The study area was 4000 km2 of unmanaged, semi-arid country in Central Australia (latitude 24.50°S, longitude 132.10°E). Horses were identified by descriptive features from ground searches, movement-activated cameras and ‘hides’ positioned at key water holes. Wherever possible, sex and age categories were documented. Population growth rate was estimated by the number of foals divided by the number of horses older than 1 year in the observed population. Results A total of 1424 horses were identified and categorised, of which 335 were foals born within the current year. Only 123 juveniles were identified. Of the adult horses, 53.4% were male and 46.6% were female and this differed from parity (P = 0.04). Of the mares, 71.9% had a foal at foot and the population growth rate was 29.5%. Conclusions With a sustained population growth rate of 29.5%, this population of feral horses will more than double within 3 years. The high population increase will likely have a detrimental effect on native fauna and flora and the fragile, semi-arid ecosystems of Central Australia. After a period of high rainfall and plentiful resources, ‘normal’ drought conditions will return and many feral horses will starve and die as they compete for limited resources. |
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1751-0813 |
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Equine Behaviour @ team @ |
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5747 |
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Doligez, B.; Danchin, E.; Clobert, J. |
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Public information and breeding habitat selection in a wild bird population |
Type |
Journal Article |
| Year |
2002 |
Publication |
Science (New York, N.Y.) |
Abbreviated Journal |
Science |
| Volume |
297 |
Issue |
5584 |
Pages |
1168-1170 |
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*Animal Migration; Animals; Animals, Wild/physiology; *Behavior, Animal; Cognition; Cues; *Environment; Female; Male; *Nesting Behavior; Probability; *Reproduction; Songbirds/*physiology; Sweden |
| Abstract |
According to the “public information” hypothesis, some animal species may monitor the current reproductive success of conspecifics to assess local habitat quality and to choose their own subsequent breeding site. To test this hypothesis experimentally, we manipulated two components of public information, the mean number of offspring raised locally (“quantity”) and their condition (“quality”), in the collared flycatcher Ficedula albicollis. Immigration rate decreased with local offspring quantity but did not depend on local offspring quality, suggesting that immigrants are deprived of information regarding local quality. Conversely, emigration rate increased both when local offspring quantity or quality decreased, suggesting that residents can use both components of public information. |
| Address |
Laboratoire d'Ecologie CNRS-UMR 7625, Universite Pierre et Marie Curie, 7 quai Saint Bernard, Batiment A 7eme etage, Case 237, F-75252 Paris Cedex 05, France. blandine.doligez@esh.unibe.ch |
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1095-9203 |
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| Notes |
PMID:12183627 |
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no |
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Equine Behaviour @ team @ |
Serial |
2841 |
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