No description available.

Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Many territorial carnivores deposit faeces and other scent-marks at specific latrine sites, and their role in territorial defence is often assumed. However, recent empirical and theoretical work suggests that ultimate explanations of territoriality differ between the sexes. In this thesis, I investigate patterns of latrine-use in cooperatively breeding meerkats, Suricata suricatta. Meerkats exhibit high reproductive skew, and in such societies an individual’s optimal investment in territory defence and intruder deterrence will depend not only on its sex, but also its breeding status within the group. The spatial and temporal distribution of meerkat latrines reflects the diversity in intruder type. Shared latrine sites between neighbouring groups facilitate costeffective monitoring of predictable intruders and surrounding land tenure. In contrast, intruding transient groups and prospecting males are effectively intercepted by latrines concentrated in the core of the territories, close to refuges. This represents the optimal strategy, as meerkat territories are too large to allow effective scent-marking around their entire peripheries, and these intruders travel between refuges during intrusions. Temporal patterns of latrine-use suggest their importance in mate-defence. Latrine-use was correlated with encounters with prospecting males and oestrous periods of resident females, and reached a peak coinciding with the season of elevated dispersal and take-over events. Additionally, rather than cooperatively contributing to territorial defence, individuals participated selfishly at latrines. Males preferentially over-marked female scent-marks and scent-marked at significantly greater rates than females, which resulted in male-biased latrines that were unrepresentative of group composition. Although all individuals investigated female scent-marks for significantly longer than male scent-marks, females invested most, suggesting that intra-group monitoring is an important aspect of latrine visits for females. The deleterious effects of close inbreeding are well known, but regular dispersal in both sexes, and long dominance tenure, result in unfamiliar siblings having a high probability of encountering one another post-dispersal. As latrines are implicated in mate-defence, olfactory assessment of factors affecting mating decisions might be expected, but although individuals do recognise foreign faeces, discrimination does not appear to occur on the basis of kinship. Together, these findings have broad implications for our understanding of individual variation and sex differences in scent-marking behaviour and territoriality. / AFRIKAANSE OPSOMMING: Baie territoriale karnivore deponeer faeces en ander reukmerke by spesifieke latrines en die latrines se rol in gebiedsverdediging word dikwels aangeneem. Onlangse empiriese en teoretiese werk stel egter voor dat die uiteindelike verduidelikings van territorialiteit verskil tussen die geslagte. In hierdie tesis ondersoek ek patrone van latrine-gebruik in samewerkend-broeiende meerkaaie (Suricata suricatta). Meerkaaie toon ‘n hoë graad van voorkeuraanwas en in sulke gemeenskappe sal ‘n individu se optimale belegging in gebiedsverdediging en indringer-verjaging nie net van sy/haar geslag afhang nie, maar ook van sy/ haar teelstatus in die groep. Die ruimtelike en temporale verspreiding van meerkat latrines weerspieël die verskeidenheid van indringertipes. Gedeelde latrine areas tussen naburige groepe help die kosteeffektiewe bestekopname van voorspelbare indringers en omringende landsbesetting aan. In kontras hiermee word tydelike groepe en geleentheidsoekende mannetjies effektiewelik voorgekeer deur latrines wat gekonsentreer is in gebiedskerne, naby aan skuilplekke. Dit verteenwoordig die optimale strategie, aangesien meerkat territoriums te groot is om effektiewe reukmerking van die hele grens toe te laat, en synde hierdie indringers tussen skuilplekke reis tydens invalle. Tydspatrone van latrine-gebruik dui die belangrikheid hiervan in paarmaat-beskerming aan. Latrinegebruik korreleer met ontmoetings met geleentheidsoekende mannetjies en die oestrus tydperk van inwonende wyfies, en bereik ‘n toppunt tydens die seisoen van verhoogde verspreiding en oornames. Ook sal individue selfsugtig deelneem by latrines eerder as om samewerkend by te dra tot gebiedsverdediging. Mannetjies verkies om vroulike reukmerke oor te merk en reukmerk teen ‘n beduidend hoër koers as wyfies, wat lei tot mannetjie-geneigde latrines wat nie verteenwoordigend is van die groepsamestelling nie. Alhoewel alle individue vroulike reukmerke beduidend langer as manlike reukmerke ondersoek, belê wyfies die meeste, wat daarop dui dat intragroep monitering ‘n belangrike aspek van latrine-besoeke is vir wyfies. Die nadelige effekte van sterk inteling is goed bekend, maar gereelde verspreiding in beide geslagte en lang dominante posisiehouding lei daartoe dat daar ‘n groot kans is vir onbekende nabye familielede om mekaar te ontmoet na verspreiding. Aangesien latrines ‘n rol speel in paarmaat-verdediging kan dit verwag word dat daar olfaktoriese beoordeling sal wees van faktore wat paringsbesluite beïnvloed, maar hoewel individue wel vreemdelinge se faeces herken, toon hulle geen onderskeidingsvermoë gebaseer op verwantskap nie. Saamgevoeg, het hierdie bevindinge wye implikasies vir ons begrip van individuele variasie en geslagsverskille in reukmerk-gedrag en terriorialiteit.

>Magister Scientiae - MSc / In the post-reionisation universe, intensity mapping (IM) with the 21 cm line of neutral hydrogen (HI) provides a potential means of probing the large-scale structure of the universe. With such a probe, a wide variety of interesting phenomena such as the Baryon Acoustic Oscillations (BAO) and Redshift Space Distortions (RSD) can be studied. The MeerKAT telescope has the potential to make full use of this technique, especially in the single-dish mode, which will probe the scales relevant to BAO and RSD. A useful complementary of this is HI IM with MeerKAT in interferometer-mode, which will enable the extraction of cosmological information on semi-linear and small scales. In this study, full end-to-end simulations of interferometric observations with MeerKAT for HI IM were developed. With this, the power spectrum extraction was analysed using the foreground avoidance technique. This took into account the foreground wedge from point source contamination extracted from real MIGHTEE COSMOS data, as well as RFI flagging. The errors on the power spectrum estimator were then calculated through a Monte Carlo process using 1000s of realisations of both the thermal noise and HI signal. In doing so, precision constraints on the HI power spectrum are found at z = 0:27 on scales 0:4 < k < 10 Mpc-1 for mock visibility data sets which contain the HI signal contaminated by noise, mimicking the MIGHTEE COSMOS field for total observation times & 20 hours. These results illustrate the potential of doing precision cosmology with MeerKAT’s MIGHTEE survey and interferometer-mode HI IM.

>Magister Scientiae - MSc / In the post-reionisation universe, intensity mapping (IM) with the 21 cm line of neutral hydrogen (HI) provides a potential means of probing the large-scale structure of the universe. With such a probe, a wide variety of interesting phenomena such as the Baryon Acoustic Oscillations (BAO) and Redshift Space Distortions (RSD) can be studied. The MeerKAT telescope has the potential to make full use of this technique, especially in the single-dish mode, which will probe the scales relevant to BAO and RSD. A useful complementary of this is HI IM with MeerKAT in interferometer-mode, which will enable the extraction of cosmological information on semi-linear and small scales. In this study, full end-to-end simulations of interferometric observations with MeerKAT for HI IM were developed. With this, the power spectrum extraction was analysed using the foreground avoidance technique. This took into account the foreground wedge from point source contamination extracted from real MIGHTEE COSMOS data, as well as RFI flagging. The errors on the power spectrum estimator were then calculated through a Monte Carlo process using 1000s of realisations of both the thermal noise and HI signal. In doing so, precision constraints on the HI power spectrum are found at z = 0:27 on scales 0:4 < k < 10 Mpc-1 for mock visibility data sets which contain the HI signal contaminated by noise, mimicking the MIGHTEE COSMOS field for total observation times & 20 hours. These results illustrate the potential of doing precision cosmology with MeerKAT’s MIGHTEE survey and interferometer-mode HI IM.

No description available.

In group living species animals commonly compete for limited resources such as food (Darwin 1859). Winning competition for food may be beneficial for an individuals survival or reproductive success (Williams 1966; Clutton-Brock 1988; Metcalfe et al 1995) but conflict with group members may be costly as it typically involves aggression (Huntingford&Turner 1987, Mesterton-Gibbons&Adams 1998). Asymmetries between individuals are predicted to determine the outcome of competition (Maynard-Smith&Parker 1976), and individuals are expected to steal food when the benefit to them is greatest (Barnard 1984; Trivers 1972). I therefore investigate what determines the outcome of competition for food between group members, and what factors affect whether group members try to steal food in the cooperatively breeding meerkat (Suricatta suricatta). Meerkats competed for food items infrequently and the owner of a food item typically won competition, but dominant individuals and breeding females were more likely to win competition than other group members. This provides support for models of conflict over resources in group living species which predict that ownership may determine the outcome of competition, thereby avoiding frequent costly conflict (Maynard-Smith 1982). Furthermore, where large asymmetries exist between contestants in dominance status or the value of a resource, these may determine the outcome of competition (Maynard-Smith&Parker 1976; Grafen 1987). Meerkats varied in how frequently they tried to steal food depending upon the costs and benefits of competition. Dominant individuals competed for food more frequently which is likely to reflect reduced costs of competition as subordinate individuals may avoid conflict with them (Packer&Pusey 1985). Females competed for food more frequently than males and more frequently during breeding, reflecting the higher costs of reproduction to females compared to males (Williams 1966; Trivers 1972). Meerkats compete more frequently for food when food availability is low, which indicates that food items may be more valuable when they are rare. Meerkats in smaller groups competed more frequently. In cooperatively breeding species group members undertake a large number of costly helping behaviours. Individuals in small groups each contribute more effort to helping than individuals in large groups and suffer higher costs which may increase the benefit of food to them (Clutton-Brock et al 1998a; Clutton-Brock et al 2001a). Competition for the opportunity to breed in cooperatively breeding meerkats has resulted in despotic dominance hierarchies where a dominant female monopolises breeding and reproductively suppresses subordinates (Clutton-Brock et al 2001b). Dominant females stole more food than any other group members. This is likely to be a consequence of the high costs of reproduction for the dominant breeding female in species with high reproductive skew (Creel&Creel 1991; Clutton-Brock et al 2001b). Furthermore, dominant females were more aggressive and more successful in competition for food with their reproductive competitors. Dominant females may therefore use competition for food as a means of asserting dominance over their reproductive competitors which could contribute to reproductive suppression (Creel et al 1992; Williams 2004; Kutsukake&Clutton-Brock 2006b; Young et al 2006). / Dissertation (MSc)--University of Pretoria, 2011. / Zoology and Entomology / unrestricted

>Magister Scientiae - MSc / The new 64-dish radio telescope array MeerKAT will be absorbed into the international Square Kilometre Array (SKA) in late 2020s. These two telescope arrays will produce three-dimensional maps of the integrated intensity of the 21cm emission from neutral hydrogen in galaxies, out to redshifts of 1:5 and 3 respectively. These maps contain a signature of the growth of large-scale structure in the Universe. This signature can be uncovered via redshift space distortions of the two-point correlation function, or power spectrum, of the 21cm brightness temperature uctuations. The growth rate governs the amplitude of the anisotropic signal from redshift-space distortions. It is a powerful probe of gravity and its measurement has the potential to test whether general relativity holds. We use models of the 21cm intensity and its power spectrum, starting from a simple linear model of redshift-space distortions and then extending to nonlinear models. With these models, we make Fisher forecast predictions of the precision with which MeerKAT and the SKA can measure the growth rate

Thesis (PhD)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: Despite more than three decades of research, and the postulation of more than 30 hypotheses of function, the adaptive significance of play remains unknown. This study quantitatively evaluated a selection of hypotheses of function, using data collected from a wild population of small, social carnivore, the meerkat, Suricata suricatta. The study found that although play in meerkats carried an energetic cost, with individuals modulating their frequency of play in response to their energy intake, none of the hypotheses evaluated by the study could identify the adaptive benefits that meerkats derived from play. Play did not increase 'social harmony' by reducing aggression between playmates, nor did it strengthen an individual's bonds to its social group, such that it remained in the group for longer, or contributed more to the group's cooperative activities. There was no evidence that meerkats used play to strengthen alliances between individuals, and young meerkats played no more frequently with their future dispersal partners than with matched controls with which they did not disperse. Play fighting experience did not improve a meerkat's subsequent fighting skills, and individuals that ultimately won the dominant breeding position within a group (through serious fighting) played no more frequently, and no more successfully, as youngsters, than the littermates that they defeated in combat. Although play was inhibited by aggression, meerkats did not use play to contest, assert or establish dominance status, and there was little evidence to suggest that the preference young meerkats showed for play partners that were well matched in age, size and ability arose from their use of play for self-assessment. This study assessed only those hypotheses of function that predicted benefits that were of importance to the inclusive fitness of the study species. For example, the enhancement of social harmony and group cohesion should be invaluable to a species whose survival is dependent upon social cooperation; and the high reproductive skew exhibited by this species places huge value upon fighting skill and the ability to win social dominance. As a consequence, this study's negative findings suggest strongly that play is not capable of providing these benefits, and that play behaviour is unlikely to be used for these purposes in any mammal species. I conclude that the most likely function of play (based on play's ubiquitous characteristics, and the findings of neurological research on rats) is the promotion of growth of the cerebral cortex. / AFRIKAANSE OPSOMMING: Ten spyte van meer as drie dekades van navorsing en die voorstelling van meer as 30 hipoteses oor funksie, bly die aanpassingswaarde van spelonbekend. Hierdie studie is 'n kwantitatiewe evaluasie van verskeie hipoteses oor funksie, en gebruik data versamel vanuit 'n wilde bevolking van 'n klein sosiale karnivoor, die meerkat, Suricata suricatta. Die studie het bevind dat hoewel spel in meerkaaie 'n energetiese koste beloop, met individue wat hul spelfrekwensie aanpas by energie-inname, geen-een van die hipoteses onder beskouing die aanpassingswaarde van spel vir meerkaaie kon verduidelik nie. Spel het nie "sosiale harmonie" bevorder deur die afuame in aggressie tussen speelmaats nie, en het ook nie 'n individu se verbintenis tot sy sosiale groep versterk sodat hy langer in die groep sou bly of meer sou bydra tot samewerkingsaktiwiteite nie. Daar was geen bewyse vir die gebruik van spel in die versterking van bondgenootskappe tussen individue nie, en jong meerkaaie het nie meer gereeld met toekomstige verspreidings-venote gespeel as met gepaarde kontroles saam met wie hulle nie uiteengegaan het nie. Speelse gevegte het nie 'n meerkat se daaropvolgende gevegsvermoëns verbeter nie, en die individue wat uiteindelik die dominante voortplantingsposisie in 'n groep gewen het (deur ernstige stryd) het nie meer gereeld ofmeer suksesvol as jongelinge gespeel in vergelyking met die werpselmaats wat hulle in die stryd oorwin het nie. Hoewel spel deur aggressie onderdruk is, het meerkaaie spel nie gebruik om dominante range te beveg, bevestig of tot stand te bring nie. Daar was min bewyse ter ondersteuning van die voorstel dat jong meerkaaie se voorkeur vir speelmaats wat hul gelyke is in ouderdom, grootte en vermoë, onstaan het in die gebruik van spel vir selfondersoek. Hierdie studie het slegs die hipoteses van funksie beskou wat voorspellings gemaak het oor die voordele wat belangrik is in die inklusiewe fiksheid van die studie-species. Byvoorbeeld, die verbetering van sosiale harmonie en groepsamehang behoort van onskatbare waarde te wees vir 'n species wat afhanklik is van sosiale samewerking vir oorlewing; en die hoë graad van voorkeuraanwas duidelik in hierdie species plaas groot waarde op gevegsvaardighede en die vermoë om sosiale dominansie te wen. Gevolglik dui hierdie ondersoek se negatiewe bevindinge daarop dat spel nie hierdie voordele kan bied nie, en dat speelgedrag heel waarskynlik nie vir hierdie doeleindes in enige soogdier-species gebruik word nie. Ek kom tot die gevolgtrekking dat die heel waarskynlikste funksie van spel (gebaseer op spel se alomteenwoordige kenmerke en die bevindinge van neurologiese navorsing op rotte) die bevordering van groei in die serebrale korteks is.

Animals in captivity can be deprived of performing some of their natural behaviours. Using enrichments may allow them to express a larger part of species-specific behaviour repertoire and with a better frequency distribution. This study focuses on three species of the family Herpestidae which live in captivity at Bioparc Valencia (Spain). The project aims to study the effect of environmental enrichment on the behaviour of meerkats, banded mongooses and dwarf mongooses in human care. To achieve this goal two different types of enrichmentswere tested: (1) a food enrichment with several variations and (2) an olfactory enrichment with the presentation of two new odours. The food enrichment aimed to increase foraging behaviour and the olfactory enrichment aimed to test if captive animals behave differently in the presence of a predator’s odour compared to a non-predator’s odour. Results revealed that foraging can increase up to 16% implementing enrichments and that success depends on the presence and quantity of food. On the other hand, animals did not seem to behave differently in the presence of both odours. The frequencies of behaviours and time spent interacting did not differ between these olfactory enrichments. I conclude that implementing enrichment programmes may ensure better welfare for captive animals.

Zoo-based research is important both to inform management decisions on captive animals and because zoos, at their best, provide a naturalistic environment, which it is possible to manipulate, in which scientific research can be performed. Extending research to multiple zoos enables investigation into how variations between zoos impact their occupants. Comparing zoo animals to their wild conspecifics can inform management decisions, improve breeding and reintroduction programmes, educate the visiting public and allow assessment of the relevance of zoo-based research to the broader field. The impact of captivity on social animals is particularly interesting, as they cannot determine their own social environment. Meerkats (Suricata suricatta) are a highly social species of mongoose which have been extensively studied in the wild, and which are common in European zoos; they are therefore an ideal focal species with which to assess the impact of aspects of the zoo environment. This thesis presents a study of the behaviour, endocrinology and morphology of meerkats in ten zoos in the UK and one zoo in Germany. The size of captive meerkats' social groups was found to influence their behaviour and faecal glucocorticoid levels (fGCs), with animals in large groups exhibiting lower fGCs, which supports an optimum group size hypothesis. Meerkats in large groups also spent less time on sentry duty, although a sentry was posted more often in zoos than in the wild, reinforcing the model of state-dependent vigilance. Captive meerkats were found to weigh much more, on average, than their wild conspecifics, with 86.7% of adults more than two standard deviations heavier than the mean weight in the wild. Meerkats in larger enclosures were heavier than those in smaller ones; their weights also correlated with climate, with zoos in cool, dry locations having lighter meerkats. This research did not find that high levels of hormonal stress occur frequently in zoo meerkats, but obesity may pose a health threat to many individuals and its impacts should be a priority for veterinary research.