The head bobbing of a walking bird is considered as an optokinetic response, but the question of why head bobbing is synchronized with leg movement is not clear. It is possible that head bobbing also has biomechanical correlation with leg movement at least during walking. Movement of the centre of gravity (COG) along the sagittal axis was estimated in pigeons Columba livia from carcasses and motion analysis from video films of walking. Although it was ascertained that the head thrust observed in the double support phase helps to shift the COG over the supporting foot around the beginning of the single support phase, its effect was very small. The hold phase showed correlation with the COG positioning over the supporting foot in the single support phase. Stabilization of the eyes during the single support phase may be significant for the control of balance.

The northern quoll Dasyurus hallucatus is a sexually dimorphic carnivorous marsupial found in northern Australia. Despite males weighing up to 1120 g, in at least some populations all males die after mating. Radio-tracking and live-trapping at a lowland savanna site in Kakadu National Park indicated that females occupied home ranges averaging 35 ha with intra-sexually exclusive denning areas. There was some overlap of foraging ranges when the density was 3–4 females/km2, but no overlap during periods of lower population density (1–2 females/km2). Male home-range size may be similar to females before the mating season, but expands during the mating season to > 100 ha to overlap extensively with several female ranges and numerous other male ranges. Despite this range overlap, both sexes were solitary. Even during the mating period, males denned on average 0.27 km from females during the day. During the mating period, each female was visited by at least one to four males per night. During this period, the increase in scat deposition in prominent positions in the landscape and the simultaneous increase in sternal gland activity of the males suggest the importance of olfactory communication to advertise the presence and sexual status of individuals. Males adopted a roving strategy, regularly visiting several widely spaced females in rapid succession, presumably to monitor the onset of oestrus. This intense physical effort during the mating period is likely to be a major contributor to the physiological decline of the males and subsequent die-off after the mating period. The marked sexual dimorphism of D. hallucatus may be the result of selection for larger, wider-ranging males in a promiscuous mating system and for energetically efficient smaller females, as females rear the young alone.

Management of whale shark Rhincodon typus populations is hampered by a lack of information on the range travelled by individual whale sharks. This applies particularly in South-east Asia where the whale shark is increasingly used in commercial trade and for ecotourism. In this study an investigation of the movements of individual whale sharks from the greater Sulu Sea region was initiated using satellite telemetry. The movements of six sharks were monitored from 7 to 128 days. Two sharks travelled distances of 4567 and 8025 km. Both sharks moved through multiple political jurisdictions, confirming the need to manage the populations on a multilateral or regional level.

Living individuals of the bivalve ‘watering pot’ superfamily Clavagelloidea were collected from Withnell Bay, Burrup Peninsula, Dampier Archipelago, Western Australia. Details of the anatomy suggest that, in most respects, Brechites vaginiferus is a typical filter-feeding bivalve, albeit encased in a tube of its own secretion. The true shell is tiny (≈ 4 mm long) and surrounded by a ‘saddle’ of initially-secreted adult shell. To this is fused, by an internally produced layer of calcium carbonate, the adventitious tube which comprises a single layer, confirming that it is produced only once. Posteriorly, however, it can be added to internally as ‘plaited ruffles’ creating a multi-layered structure. The anterior watering pot comprises a perforated plate fringed by tubules, with a small pedal aperture. Brechites vaginiferus pumps interstitial water into the mantle cavity via the watering pot, at least principally, not out of it as previously thought. In this way, the animal is either tapping an interstitial source of accessory food, or aerating the anterior end of its burrow (or both). It has also been demonstrated, however, that pumping interstitial water into the mantle cavity via the pedal gape results in hydraulic pressures being built up that extend the siphons. The pedal disc pump, therefore, acts in this amyarian bivalve in the same way as the adductor muscles do in more typical species. The ctenidia collect suspended material in the usual way from seawater and from interstitial water: they do not, however, possess chemoautotrophic sulphur-oxidizing bacteria, and the species is thus not using sulphur as an energy source. Pedal gape feeding is considered to be the ancestral condition not only in the earliest anomalodesmatans, e.g. the Pholadomyidae, but also the autobranchs in general. This has been refined in the Clavagelloidea to create the unique form of the adventitious tube, its watering pot and a wholly surprising lifestyle. Tube form in B. vaginiferus varies in relation to habitat occupied. Its major habitat on Withnell Bay, however, is the riffles of a high-salinity stream draining down the mangrove-fringed shore from the semi-arid land behind. Although much more is now known about B. vaginiferus and ‘watering pot’ shells, no pre-tube juvenile is known and awaits discovery to confirm hypothesized life-history details.

Giant pandas Ailuropoda melanoleuca are a solitary, seasonally mono-oestrous species, and as such are likely to rely heavily on chemical signals to co-ordinate mating efforts. Perhaps the most crucial chemosensory task facing male pandas is the assessment of female reproductive condition on the basis of chemical cues. To test for this ability, eight male and 10 female giant pandas were presented with urine from oestrous and non-oestrous females. Males but not females displayed a significant investigatory preference for oestrous over non-oestrous female urine, as indicated by sniffing and flehmen. Males also investigated, displayed flehmen, and licked female urine more than did females. These findings indicate that female urine contains chemical cues permitting discrimination of oestrous status, and probably serves a reproductive advertisement function. The prevalence of flehmen and licking by males suggests that males may rely on the vomeronasal organ to assess female reproductive condition. Female odours may play an important role in the reproductive behaviour of male giant pandas and, therefore, may have implications for captive-breeding programmes.

Armadillos are a very diverse group ranging from non-fossorial Tolypeutini through to the powerful diggers like the giant armadillo Priodontes maximus to the totally subterranean Chlamyphorini. A previous study demonstrated a close relationship between the relative length of the olecranon of the ulna (index of fossorial ability, IFA) and the fossorial ability of armadillos. This study examines a wide range of limb proportions to explore the biomechanical correlates with fossorial ability. The study demonstrates that the indices of the forelimb (brachial index, shoulder moment index and IFA) do correlate well with digging habits, but also reveals some interesting exceptions, particularly in the most fossorial and most cursorial forms. On the other hand, the hindlimb indices apparently do not correlate with digging habits, but seem to be influenced more by body size. The correlations among the forelimb indices are quite strong and positive but correlations between forelimb and hindlimb indices are negative or very low. It is apparent that there is still much to be learned about structure and function in armadillos.

The majority (98%) of the 174 female elephants in South Africa's Addo Elephant National Park are tuskless. Long-term records are used to assess trends in tusklessness in this elephant population throughout the 20th century. These data are then used to test hypotheses of possible causes of this tusklessness. It is shown that attributes of the region's vegetation (structure and/or nutrient composition) and selective hunting cannot provide adequate explanations for the high frequency of tusklessness among the Addo elephants. Non-selective genetic changes resulting from the population's isolation, small size and bottlenecks (during the 1800s and 1920s) are suggested to be primarily responsible for the observed tusklessness. The rapid increase in the frequency of tusklessness during the past 70 years provides a phenotypic indicator of underlying genetic drift.

Sexual dimorphism in the primate face has been studied intensively lately, but a number of issues remain controversial. For example, some studies have indicated that facial sexual dimorphism arises through ontogenetic scaling, whereas others have found it to be a consequence of both ontogenetic scaling and divergence in male and female growth trajectories. To shed further light on primate facial sexual dimorphism, geometric morphometric methods were applied to crania representing five papionin genera: Cercocebus, Lophocebus, Macaca, Mandrillus and Papio. A first set of analyses focused on the pattern and degree of facial sexual dimorphism exhibited by adult specimens. A second set of analyses concentrated on the ontogeny of facial sexual dimorphism in infant-to-adult age series. The first set indicated that the five genera exhibit significant facial sexual dimorphism. These analyses also revealed that the genera share several features of sexual dimorphism. Males are distinguished from females in having a more prognathic mid-face, a relatively more inferiorly and anteriorly positioned prosthion, relatively increased subnasal height and relatively broader zygomatic roots. They are also differentiated from females in their maxillae, which relative to the zygomatics are narrow but vertically deep, especially in the posterior aspect. Also, the first set of analyses indicated that Macaca is the most distinctive of the genera in terms of sexual dimorphism. The distinctive features of the Macaca sexual dimorphism are that males exhibit relatively wider nasal apertures and premaxillae than females, together with a relative increase in breadth across the inferior zygomatic roots. The second set of analyses demonstrated that in all the genera, sexual dimorphism arises partly through ontogenetic scaling and partly through a late divergence in male and female growth trajectories. The analyses also indicated that the relative contribution of these processes to sexual dimorphism varies among the genera. Ontogenetic scaling is by far the most important process in Lophocebus and Papio. Late divergence between male and female growth trajectories contributes proportionately more in Cercocebus and Mandrillus, although ontogenetic scaling still plays the major role. The relative contribution of late divergence between male and female growth trajectories is greatest in Macaca, in which it accounts for about half of the facial differences between adult males and females. In all five genera, ontogenetic scaling results in increased prognathism and greater relative maxillary size in males compared to females, whilst the late divergence involves the male mid-face becoming proportionately larger and deeper than the female mid-face, and the male posterior maxilla coming to lie more inferiorly with respect to the zygomatic root than its female counterpart.

Home ranges, spatial movements and patterns of habitat use were determined during a radio-tracking study on four male and six female Philippine tarsier Tarsius syrichta in Corella, Bohol, from early March to October 1999. This was the first radio-tracking study of the Philippine tarsier that included both breeding adult males and females. Home ranges averaged 6.45 ha for males and 2.45 ha for females (MCP and Kernel 95%), allowing for a density of 16 male and 41 female tarsiers per 100 ha. The habitats are primarily located in secondary lowland rainforest in early to mid succession stage, but individual tarsiers readily traversed open grass areas to move between forest patches. However, the tarsiers avoided adjacent residential areas, clearings and agricultural plantation, even if the last two were found enclosed in home-range polygons. The home range of one male overlapped extensively with that of one female and to a lesser extent with a second female. Home ranges of males showed little overlap (2.71%) and the same was observed among the females (3.35%). Nightly travel distance averaged 1636 m for males and 1119 m for females. Individuals were observed to forage and sleep solitarily. The tarsiers form groups of one adult male and one or two adult females and their offspring.

In our study area in Zimbabwe, half of the fresh-weight biomass of the diet of side-striped jackals Canis adustus comprised small and medium-sized mammals, and a further third consisted of fruit. Three types of mammal (multimammate mice Mastomys spp., bushveldt gerbil Tatera leucogaster and scrub hare Lepus saxatilus) and four species of fruit (mobola plum Parinari curatellifolia, chocolate berry Vitex payos, wild fig Ficus natalensis and waterberry Syzigium guineense) dominated these categories. Captive jackals significantly preferred animal prey items to fruits, and these were also the items that contained the highest levels of apparent available energy and organic matter. Wild jackals, however, did not spend more time in the habitats in which mammals were most abundant, nor did they eat more of them during a period of higher prey population density. We conclude that the feeding of jackals is largely geared by searches for fruit, and that mammals are taken opportunistically when they are encountered.

This study examined how spatial variation in flow regime affects patterns of tadpole distribution in Birthday Creek, an upland rainforest stream in northern Queensland. Tadpoles of Litoria genimaculata and Mixophyes schevilli are restricted to habitats with little or no water flow, and L. nannotis and Nyctimystes dayi occur only in rapidly flowing and turbulent riffle habitats. The abilities of L. genimaculata, M. schevilli and L. nannotis to resist flow rates typical of riffle habitats were compared in a laboratory flow chamber and in an artificial riffle in the field. In the flow chamber, large tadpoles of L. genimaculata were more resistant to flow rates of 25 cm/s than were smaller individuals, but at 50 cm/s all tadpoles were dislodged irrespective of size. Large M. schevilli tadpoles were significantly more resistant than were smaller individuals only at the fastest flow rate. Large (> 25 mm body length) M. schevilli were resistant to the highest tested flow rates (50 cm/s), but in an artificial riffle with turbulence typical of a riffle both Litoria genimaculata and Mixophyes schevilli were rapidly dislodged irrespective of their size. Fast water speeds had little impact on L. nannotis in the flow chamber or in the artificial riffle. Litoria nannotis and other tadpoles living in riffles have evolved a range of morphological and behavioural traits that minimize exposure to, and maximize resistance to, fast-flowing turbulent water within these habitats. The results of this study indicate that L. genimaculata and M. schevilli cannot live in riffles because they are unable to withstand the flow rates typical of these habitats.

Allometric analyses of the three major salivary glands of 44 tammar wallabies Macropus eugenii and 58 parma wallabies Macropus parma from Kawau Island, New Zealand, indicate that tammar wallabies have larger parotid glands while parma wallabies have larger mandibular glands. The difference can be related to the importance of cooling in tammars, an arid-zone species, and the need for greater buffering of forestomach digesta in parma wallabies because of their greater daily food intakes and a higher browse component in their natural diet. Comparisons of sublingual gland size of these two species viewed in terms of their capacity for mucus production suggest that this may be influenced by the need to protect mucosa from mechanical and chemical injury from browse. Sample sizes of brush-tailed rock-wallabies Petrogale pencilliata and swamp wallabies Wallabia bicolor were too small for similar statistical comparisons, but they confirmed that salivary gland histology was broadly similar among all four species.

Forty leghorn chickens at the commencement of egg laying, were divided into two groups, each with 10 females and 10 males. One group was exposed to the odour of synthetic pyrazine (2-methoxy-3-isobutylpyrazine) for 16 weeks while the other acted as a control. During the first 4 weeks the hens exposed to pyrazine odour laid significantly fewer eggs (unfertilized) than the controls, but thereafter both groups laid a similar number. Mean egg mass of the pyrazine exposed hens was significantly (P = 0.012) greater (5.5%) than that of the control group. No significant difference was found in body mass or eggshell thickness. Similarly, there were no consistent significant differences between groups in oestrogen and testosterone concentrations in the blood of females and males, respectively. No pyrazine could be detected in cloacal extracts. The experiment shows that an external odour can affect the internal reproductive system of the chicken. It is suggested that the pyrazine-engendered increase in egg mass involves neuroendocrine regulation within the hypothalamus rather than hormonal interactions ‘downstream’ of the brain.

Pairing of the X and Y chromosomes during meiotic prophase and the G- and C-banding patterns were analysed in Microtus sikimensis. The karyotype of M. sikimensis from central Nepal, has 2n = 48 and FNa = 56. It has been derived from the all single-armed karyotype of M. carruthersi through a unique course of evolution. There is a synapsis between the X and Y chromosomes at pachytene and end-to-end association from diakinesis to metaphase I. Microtus sikimensis has no close karyological or morphological relationship to the other synaptic species studied so far. These data confirm that several species or lineages with synaptic condition exist in the genus Microtus, and that the ancestor of Microtus had synaptic sex chromosomes.