The timing of emergence of green turtle (<i>Chelonia mydas)</i> hatchlings from their nest on two beaches on Ascension Island was monitored. Emergence of hatchlings predominantly occurred at night, and was inhibited by increasing temperatures at superficial sand depths. No single thermal cue was found to play a role during the emergence of loggerhead turtle (<i>Caretta caretta)</i> and green turtle hatchlings from their nests on Cyprus. No difference in temperature within loggerhead and green turtle clutches was observed in northern Cyprus and on Ascension Island. The magnitude of metabolic heating during the final third of incubation, was positively related to clutch volume. A comparison of body size and flipper size was carried out on green turtle hatchlings from Ascension Island and Cyprus. Ascension Island hatchlings were larger than hatchlings from Cyprus. Incubation temperature appeared to influence body size on Ascension Island, with higher temperatures producing smaller hatchlings. Rhythmic throat movements were recorded during the various nesting stages of green turtles on Ascension Island. Throat movements occurred consistently during the various stages, although were statistically lower during egg deposition. Female green turtles were weighed post oviposition during nesting at Ascension Island. Turtles were found to lose 0.22kgd^-1, as they do not feed during their time at the island. A dichotomy in depth utilisation between green turtles during their interesting interval in Ascension Island and Cyprus was observed. This difference was attributed to differences in food availability at the two sites. Depth and swim speed during U-dives carried out by a green turtle were measured during the inter nesting period in Cyprus. Typically the turtle initially descended at a steep angle (around 60°) but as the dive continued this angle lessened until the turtle approached the seabed at an average angle of about 15°.

The behavioural and adrenocortical effects of differentially housing mice were investigated. 'Isolated' male mice were found to show progressively increased fighting with increased duration of housing. 'Isolated' and grouped (6) mice had similar 'basal' corticosterone titres but the former had elevated 'stress' values of this hormone following longer differential housing. Young mice showed more fighting after short periods of 'isolation' than older animals. The effects of duration of and age at differential housing on behaviour in open field and emergence tests wore investigated. Neither sex seemed particularly 'stressed' when individually housed but 'isolated' males if compared with grouped counterparts did appear more 'reactive' in their behavioural and adrenocortical responses to novelty and stress. Other experiments contrasted 'isolates' with identified dominant and subordinant mice from pairs. 'Isolates' were found to be more like dominants in their intermale fighting; body weight; and adrenal and sox accessory gland weights than subordinates. 'Basal' plasma corticosterone values were similar in all categories. Separation of pairs of mice using three different partitions which allowed passage of different amounts of sensory input did not significantly influence isolation/pairing comparisons. Removal of tactile vibrissae, induction of anosmia and housing with odoriferous (?) substrates all altered the incidence of fighting in 'isolated' mice. 'Total isolation' did not seem quantitatively different from individual-housing. These findings suggest that:- (a) 'Isolation' can not be dismissed as a 'stress' in this species; (b) The adrenals of the 'isolated' males are more 'reactive' to superimposed stress than those of grouped animals. This may account for some claims that 'isolation' is stressful; (c) 'Isolated' males are more similar to dominant than to subordinate mice. It seems likely that group housing reduces the ability of the majority of mice to exhibit aggressive behaviour; (d) Physical contact seems responsible for most of the changes in 'isolation'/grouping comparisons. However, differing amounts of communication between neighbouring cages could account for some variability between studies.

The present thesis essentially applied detailed etho-logical techniques of videotaped records to assessing the impact of non-biological factors on social encounters in laboratory House mice. They generated a much more complete description of the effects of manipulations on behaviour. 'Isolated' male Swiss mice showed increased fighting after even short durations of such housing. Young mice showed more fighting after this procedure than did older animals. The grouped mice exhibited much less aggressive responsing when compared with the isolated counterparts. The age at testing for aggressive behaviour is very important, as is the duration of isolation. One should emphasize that many aspects of behaviour are changed by this housing condition - aggression may not be the most important. Separation of pairs of mice using three different partitions allowing passage of different amounts of sensory input did not significantly influence isolation/pairing comparisons. The neighbouring animals did not show reduced aggression when non-physical contact was possible. Physical contact seems very important in familiarization processes in these animals. Familiar intruders are generally attacked much less vigorously than unfamiliar mice. Animals which had had positive fighting experiences also attack more than individuals lacking such experience. This illustrates the necessity of adequately reporting past history of experimental animals. Levels of aggressive behaviour were relatively high in this strain of mouse when given 24 hours experience of 'prior residence'. Prior residence augments aggression but not dominance potential in these mice. The present studies confirmed that a systematic evaluation of features such as familiarity (of the animals and their situations), and the past history of the animals (such as experience) are necessary to understand social organizations, even in mice. An attempt was made to relate the effects of experience and environmental factors on feral populations of animals.

Male loggerhead turtles (<I>Caretta caretta</I>) were observed in a shallow (< 2 m) lagoon. Preferred food sources were <I>Mytilus galloprovincialis, Posidonia oceanica</I> and discarded fish entrails. Foraging dives were of short duration, presumably because of the small lung volumes required to attain neutral buoyancy at shallow depths. In-water observations of juvenile hawksbill turtles (<I>Eretmocheyls imbricata</I>) were made. Curved carapace length was estimated to within 10 cm of actual size. Foraging grounds of adults and juveniles did not appear to overlap. Juvenile hawksbills alternated between short, shallow foraging dives and deeper, longer resting dives. Time depth recorders were attached to loggerhead turtles (<I>n</I> = 2). Dives to the seabed (< 20 m) accounted for 59% and 755 of the interesting interval. Benthic dives decreased markedly following or prior to a nesting event. This contrasted the predominance of open-water dives reported in Japan. Open-water resting may occur when turtles are travelling and, conservely, when little time is spent travelling turtles opt to remain predominantly on the seabed. Atypically deep v-dives were identified for loggerhead and green (<I>chelonia mydas</I>) turtles. These appeared pre-determined, within the physiological scope of the species and may allow direct bathymetric information to be gathered. Patterns of hatchling emergence were documented and related to in-nest thermal conditions. Variation existed between and within individual nests. Hatchlings from nests displaying large thermal range emerged over a longer time-scale than those with more uniform temperatures. Incubation during data were used as a proxy of sex ratios. Variation existed within and between nesting seasons with 'atypical' seasons characterised by predominantly male production. Egg failure and neonate mortality were investigated in loggerhead clutches. First clutches were more likely to contain a higher proportion of eggs displaying no gross signs of development. Possible factors underpinning this are explored as are its implications at population level.

Many of the early studies which attempt to relate hormones to 'aggression' have methodological problems. Consequently, one thousand, six hundred and twenty-seven male mice rendered aggressive by breeding experience were used in a series of studies to assess the abilities of sex steroids to maintain post-castrational aggressiveness. A range of relatively low doses of oil-based intra-muscular injections of androstenedione; testosterone; 19-hydroxytestosterone; 5a dihydrotestosterone; 50 dihydrotestosterone; androsterone; 5a 19-hydroxydihydrotestosterone; oestradiol benzoate; oestradiol-l70; oestrone; oestriol; diethyl stilboestrol and 2a, 7a dimethyl androst-5-en-30, 170-diol were assessed for both behavioural and somatic actions. The results indicate that: (i) Steroidal and non-steroidal oestrogens are more behaviourally potent (on weight injected basis) than any other investigated compounds. This suggests that possession of an aromatized 'A' ring augments potency with respect to fighting behaviour. (ii) Aromatizable androgens are behaviourally and somatically potent whereas nonaromatizable (5a-reduced) compounds generally have low behavioural and high somatic potencies. However, 5mDHT does maintain behaviour so one cannot argue that 5a reduction abolishes the ability to maintain aggressive motivation. 5aDHT may, however, be an unusual compound. (iii) 19-hydroxylation seems to reduce both behavioural and somatic potencies. Subsequently, the abilities of a variety of anti-androgens, anti-oestrogens, aromatase inhibitors and progesterone to suppress androgen or oestrogen maintained fighting were investigated. The most striking finding here was that the anti-aromatase blocked testosterone but not oestrogen-maintained fighting. The results provide strong support for the suggestion that aromatization of androgens to oestrogenic metabolites has a potent effect on their ability to maintain fighting. It is not certain, however, whether this conversion is obligatory. The results do, however, strongly indicate the need to consider the effects of possible metabolic conversions of applied steroid treatments when assessing the effects of hormones in both animal behavioural and clinical studies.

No description available.

The aim of the present study was to investigate certain aspects of behavioural ecology in a feral pony population living on commonland in the Gower peninsula, Sough Wales. In addition, the relationship between a mare and her foal was examined, with a discussion of foal development. The relationship between behaviour and the environment has been the subject of many studies. In the Gower populations on Pengwern and Fairwood Commons, changes in activity patterns were recorded between months of observations. Predicatably, time allocated grazing varied significantly between months as did time allocations to locomotion and social behaviour. The direction of variation was essentially towards an increase in time allocated to foraging during the winter months, with an associated increase in locomotion reflecting the necessity to forage at a variety of locations. It was suggested that forage availability plays a major role in determining behaviour patterns, for example spacing between individuals increased during the winter months when more time was allocated to foraging. A marked variation was recorded in the pattern of use of the available habitat, different areas of the habitat being exploited during different months. For each aspect of behaviour considered, possible variations between lactating and non-lactating females were examined. The pattern in variation was not consistent. The same considerations were applied to animals grazing on a tidal marsh. Essentially, variation in behaviour was similar to that recorded on the inland study sites. However, behaviour did not appear to be influenced to a significant level by the state of the tide. The constraints of the regular fluctuations in tide were discussed in relation to forage availability. Selection of forage plants by subjects was monitored on both study sites. Using information gained from a novel and unusual method, the energy intake per day was estimated for these subjects. It appeared the animals were able to satisfy the predicted energy requirements from grazing on the vegetation available. Development of selected individuals from birth to six months was monitored. Activity patterns showed marked changes during this period. Grazing became a more predominant activity with a corresponding decrease in suckling. Differences were recorded between sexes in time allocated to social interaction, male foals being involved in social interaction to a greater degree than females, for example in naso-nasal investigation, mutual grooming, group play and agonistic interactions. In connection with developmental changes in offspring, changes were recorded in the relationship between a mare and her foal. The distance between a mare and foal increased as the foal developed independence. Investment via suckling was examined. There was no difference recorded in investment in male and female foals, contrasting with the findings of other authors. Maternal experience did not appear to significantly influence the relationship between a mare and foal, as recorded in proximity and suckling. The effect of orphaning on a 100 day old foal was assessed. The data suggested the individual was capable of survival without its mother and its behaviour did not differ significantly from the other subjects of the same age.

The thermal sensitivity of the common brown shrimp Crangon crangon L. and the prawns Palaemon serratue (Pennant) and Palaemon elegana (Bethke) was investigated by studying their behaviour both in their natural environment and in the laboratory. The annual migratory cycle of Crangon, previously reported by others, was confirmed in Swansea Bay, S. Wales. The shrimps migrate offshore in autumn and start to return in early spring. The return migration is interrupted by an offshore breeding migration in April. A correlation was shown between the timing of the autumn offshore migration and the time when shallow water near the shore became colder than deeper offshore water. The return migration coincided with the temperature reversion. Laboratory observations revealed that temperature changes affect the activity of shrimps. It is suggested that this effect provides a mechanism for the annual migratory cycle involving differential tidal transport. Lethal temperature values were determined for different sex and size categories of Crangon in summer, spring and winter, and some comparisons were made with. P. serratus and Carcinus maenas (L.). The relevance of lethal temperatures is discussed in relation to the temperatures experienced by shrimps and prawns in their natural environment. True thermal discrimination was demonstrated is Crangon using choice chambers. Shrimps acclimated at 20-22°C avoided temperatures of 28.8°C and 9.0°C in a Y-maze, and showed a preferendum at 15-22°C in a total range of 15-30°C. A nociceptive sensitivity to temperature was also shown by means of localized and generalized methods of stimulation. Both thermal sensitivity levels and nociceptive thresholds changed with corresponding changes in acclimation temperature. The potential sensory repertoire of the antennal flagellum of Crangon and Palaemon spp. was described by the use of light and scanning electron microscopy. Four kinds of possible receptor were found: setae in groups, single setae, pits with a central dome and simple pits.

Ethoexperimental techniques were applied to reassess sex steroid influences on social encounters in laboratory rodents. Parallel investigations on Lister Hooded rats and TO strain albino mice were completed, with treatments being applied to individually-housed rodents. Same-sex rats and mice were paired in combinations here a) both members were surgically-manipulated/injected with active material, b) both rodents were sham-operated/injected with control solutions or c) the subjects were treated differently. All three kinds of pairing were videotaped (60 and 10 minutes for rats and mice, respectively). Paired rats inhabited a large partitioned cage for 24 hr before the encounter whereas some mice were transferred to their partner's cage immediately before testing. Tapes were analysed by assessing the times allocated to broad behavioural categories of non-social investigation, social investigation, offense, defence, sexual activities (including genital sniffing) and immobility. The effects of castration of males (10 to 20 days previously) and ovariectomy combined with testosterone propionate treatment of female were studied. Intact males were treated for 4 or 8 days with progesterone (25mg/kg for both rats and mice), the anti-androgen cyproterone acetate (25 and 50 mg/kg for rats and mice) and the anti-oestrogen tamoxifen (500 and 1000 μ for rats and 50 and 100 μ for mice). Accessory gland weights were obtained to confirm treatment effectiveness. Similar data were obtained for rats and mice with complex treatment effects on social encounters. Offense <i>and</i> sexual behaviour were reduced by castration whereas immobility increased. Testosterone treatment of ovariectomized females generated offense. Progesterone reduced offense but increased immobility. Cyproterone acetate reduced offense and sexual behaviour. Tamoxifen mainly reduced offense. Significant changes in defence always seemed consequences of attack to which animals were subjected. Immobility could not be simply regarded as passive defence. Organ weight changes generally confirmed treatment effectiveness. Such tests are valuable for revealing complexities of drug/hormone actions but the data was often similar to that obtained from 'standard opponent' tests.

During spring and summer 2003 data were collected from the leatherback population nesting on a beach in Grenada, West Indies. By attaching data logging devices to leatherbacks I was able to record certain aspects of their behaviour whilst at sea between nesting events. Three different device types were used in these studies: Satellite Relayed Data Loggers (SRDLs), Time depth recorders (TDRs) and mouth opening sensors. The SRDLs as well as providing location fixes, transmit limited dive data to overpassing satellites. After introducing various aspects of leatherback biology and ecology (chapter 1) and describing the methodologies used to collect and process the data (chapter 2) I then go on to validate this data collected by the SRDLs (chapter 3). This was achieved by attaching, to the same animal, an SRDL and a TDR (which record depth and temperature at a predetermined sampling interval). The fourth chapter focuses specifically on the data acquired by the TDRs particularly in relation to diel periodicity and the function of deep dives. Chapter five pertains to the crepuscular diving behaviour of leatherbacks. In this chapter I predict how the turtles will behave according to optimal foraging theory and then investigate these predictions using the data collected by the TDRs. Chapters six and seven involves a thorough investigation into the mouth opening data collected. In chapter six I examine the breathing patterns and mouth opening behaviour of the turtle during dives whilst in chapter seven I focus on some unexpected oscillations being recorded by the mouth opening sensor.