Morphometric data from Fennoscandian populations of the crested newt Triturus cristatus and the smooth newt Triturus vulgaris were analysed for the presence of sexual size and shape dimorphism. The data sets included nine body-related and nine head-related measurements and were examined with univariate, bivariate and multivariate methods. Sexual dimorphism was demonstrated in both species. The separation of specimens was highly related to sex. Although the expression of sexual dimorphism differed between the two species, some patterns were shared. These are discussed in terms of evolution of intersexual dimorphism according to models of ecology, fecundity and sexual selection. In multivariate analyses, sexual dimorphism was restricted to body-related variables such as standard length and distance of extremities (with high values for females), contrasting against cloaca and limb-related characters (with high values for males). In both species, the ‘distance of extremities’ measure (i.e. trunk length) was one of the strongest sexually dimorphic traits. No evidence of sexual dimorphism in head morphology was found. The results are interpreted as primarily concordant with theories on fecundity selection. For example, it has been suggested that females with larger trunk volumes increase their reproductive capacity. The fact that males had longer extremities, in relation to other characters measured, could be attributed to sexual selection. Long limbs in male newts may be beneficial for courtship performance. Since head-related characters did not show any patterns of sexual dimorphism, no evidence was found to suggest that male and female crested and smooth newts have adapted to different feeding strategies.

The southern cassowary Casuarius casuarius johnsonii is endemic to the tropical rainforests of north-eastern Queensland, Australia. This species is Australia's largest bird and holds a reputation for being dangerous. Cassowaries and ostriches are the only birds world-wide that have caused human deaths by physical attack. Incidents occur every year in Queensland, most at Mission Beach (110 km south of Cairns) and Lake Barrine (39 km south-west of Cairns), but previously also at Mount Whitfield in Cairns. The incidence of cassowary attacks in Queensland is reviewed. Data were obtained for 221 cassowary attacks, of which 150 were against humans, 75% of these by cassowaries fed previously by people. The feeding of cassowaries appears to change their natural behaviour, making them bold and aggressive. Victims were chased or charged in 71% of the incidents, and kicked in 15%. Less frequent actions included pushing, pecking, jumping on, butting with the head and snatching food. The cassowaries appeared to be expecting or soliciting food from humans (73% of the incidents), defending food (5%), and defending themselves (15%) or their chicks or eggs (7%). Contrary to popular belief, jogging did not incite cassowaries to attack. Although cassowaries should not be considered dangerous, they can cause serious injuries. Seven attacks against humans resulted in serious injuries (puncture wounds, lacerations, broken bone) and subsequently one death, caused by cassowaries kicking or jumping on victims. In the single fatal attack, the victim was trying to kill the cassowary. Four of the seven seriously injured victims were crouching or lying on the ground.

Grouping behaviour, tail-biting behaviour and sexual dimorphism were investigated in Cordylus cataphractus, a rock-dwelling lizard from South Africa. Eighty-five per cent of individuals collected during different seasons occurred in groups of two or more, which shows that grouping behaviour is a year-round phenomenon in this species. Group size ranged from one to approximately 30. Groups smaller than nine individuals normally included only one adult male, but larger groups often had more than one. Sixty-eight per cent of lone individuals were adult males. All individuals (n = 134) attempted to bite their tails and roll into a ball on collection. Cordylus cataphractus prefers horizontal crevices with an accompanying ledge on which animals can perch in close proximity to the crevice. Males apparently reach larger asymptotic body sizes than females and also have larger heads and longer tails. The higher incidence of scars among males suggests that sexual dimorphism could result from sexual selection, but sexual differences in scaling of head and tail dimensions, however, suggest that the dimorphism may be the result of differential energy allocation by females. Unlike most other Cordylus species which have female-biased sex ratios, the ratio is close to one in C. cataphractus.

The trunk-like proboscis of tapirs provides a prime case study in the evolution of anatomical novelty. Morphological study of this unique structure was undertaken employing several specimens and a combination of analytical techniques: gross anatomical dissection, radiographic imaging and histological sectioning. Evolution of the proboscis of tapirs entailed wholesale transformation of the narial apparatus and facial architecture relative to perissodactyl outgroups. This transformation involved retraction and reduction of the bony and cartilaginous facial skeleton, such that several structures present in outgroups are completely absent in tapirs, including cartilages surrounding the nasal vestibule (e.g. alar and medial accessory cartilages, rostral portion of the nasal septum) and associated musculature (dilatator naris apicalis, lateralis nasi pars ventralis). At the same time, soft tissues surrounding the upper lip and nose became elaborated to form a mobile, fleshy proboscis. Several key facial muscles (e.g. levator labii superioris, levator nasolabialis, caninus, lateralis nasi) have been co-opted to function in movement of the proboscis. The nasal vestibule is expanded and occupies approximately 75% of the nasal cavity. Vestibular expansion has compressed and simplified caudal components of the nasal cavity (e.g. reduction of dorsal and middle nasal conchae, loss of plica recta and plica basalis). The airway has become dorsally arched causing the ventral conchal complex to become inclined relative to the long axis of the skull. A few anatomical enigmas remain, such as the complicated maxilloturbinate that rostrally contacts the nasal septum and vomeronasal organ. Similarly, the meatal diverticulum, despite being both ancient and anatomically complex, has no obvious functional significance; it is clear that it is not homologous to the nasal diverticulum of horses and other equids. The reduction of the osseocartilaginous portion of the proboscis, coupled with expansion of the muscular and connective tissue components, has resulted in an organ that is best interpreted as a muscular hydrostat.

Populations of Potamonautes perlatus were sampled at various points along the Olifants Rivers (220 km), in the Western Cape to examine the degree of genetic variation. Allozyme electrophoresis revealed a near fixed allelic difference at one locus and extensive differentiation at another locus between populations from the upper and lower reaches of the Olifants River system. Limited hybridization in the region of population sympatry was observed. The narrow hybrid zone and the low occurrence of hybrids suggest selection against hybrids. These results provide evidence for two genetically distinct freshwater crab populations. We concluded that the genetic divergence between the two population groups represents a species boundary between the two populations.

Adaptations to extreme environmental conditions were investigated in a detailed study of red foxes Vulpes vulpes inhabiting a desert region of Saudi Arabia. Forty-two adult foxes were live-trapped during 3 years of field work. In contrast to red foxes studied in other areas, no strict territoriality was observed in this population. Although close interaction (separation < 1 m) was more common between members of the same, rather than different, social groups, medium distance interactions were similar. Further, intra-group encounters were much less common than for foxes in the U.K., and foxes did not avoid each other at territory boundaries. All foxes used food-rich sites associated with human activity, and aggregations of up to four foxes were regularly seen in these areas. It is suggested that the combination of an extremely harsh environment, with spatially and temporally variable food supplies, leads to the formation of loosely knit social groups. Saudi Arabian red foxes followed Bergmann's rule in being considerably smaller than those found in cooler areas. They also had a lighter coloured pelage than red foxes typical of Europe and North America. These morphological differences may represent adaptations to the low availability of food and rest sites in the desert.

The girdled lizard Cordylus macropholis inhabits semi-desert areas along the west coast of South Africa. Unlike many other small diurnal lizards living in open habitats, it exhibits extreme low levels of above-ground activity and does not show overt thermoregulatory behaviours, such as basking or shuttling. It has an extreme low movement rate and confines routine activity to the microhabitat of the succulent Euphorbia caput-medusae. We document this restriction of activity in time and space in relation to aspects of this lizard's thermal biology. Throughout the day, a majority of the lizards was found sheltering (‘covered’) among the branches of E. caput-medusae plants, and surface-active (‘exposed’) individuals were seen during only a restricted time period (i.e. 1100–1700 h). Mean body temperatures (Tbs) of both ‘exposed’ (29.4 °C) and ‘covered’ (28.4 °C) individuals were surprisingly low for a lizard inhabiting a hot and dry climate zone. This similarity of the Tbs of both groups, as well as the correspondence between the ambient temperatures in the plant microhabitat and the Tbs of ‘exposed’ lizards indicate that, for a considerable part of day, thermal conditions under plant cover allow achievement of Tbs at a similar level as that maintained by the ‘exposed’ lizards. Moreover, the absence of sightings of overtly basking lizards supports the view that C. macropholis warm up by adopting the ambient temperature in their shelters thereby reducing the time spent in surface activity. All lizards observed were within the periphery of E. caput-medusae plants, indicating that C. macropholis is an extreme microhabitat specialist. The succulent provides more and safer hiding places than other common shrubs in the environment. In addition, estimates of ambient temperatures indicate that these plants offer superior opportunities for thermoregulation compared with other available shrub microhabitats.

Although small, nocturnal, fossorial snakes are a significant component of the reptile fauna in many parts of the world, their biology is poorly known. An 11-year pit-trapping study in urban bushland remnants near the city of Perth, Western Australia, provided data from >500 captures of small fossorial snakes of the genus Simoselaps. The five species differed in relative abundances and in distribution, both among localities and among habitats within a single locality. For example, three saurophagous taxa (Simoselaps bertholdi, S. bimaculatus, S. calonotos) were most abundant in Banksia woodland, whereas two species that feed on reptile eggs (S. semifasciatus, S. fasciolatus) were most abundant in coastal heath. Capture rates for most species were low (for three of the five species, <one specimen captured per 1000 trapdays), and these taxa may be genuinely rare in most of the habitats that we surveyed. Activity patterns were highly seasonal, with little activity in winter or in midsummer. The two oophagous species showed a more restricted activity period (late spring–early summer) than did species with broader dietary habits. In the most abundant taxon (Simoselaps bertholdi), males were active mainly during spring (the mating season) and females during autumn, after oviposition. Capture rates and body condition of the captured snakes varied substantially among seasons and across years. Low capture rates mean that very prolonged surveys are needed to determine reliably whether or not a taxon occurs on any given site.

Pupping seasonality, annual pup production, reproductive rate and sex ratio at birth were determined for the Mediterranean monk seal Monachus monachus colony at Cabo Blanco, the only surviving population of the species which still shows a colony structure. Data were collected by means of a monitoring programme that operated continuously in the main reproductive areas of the population during the period March 1993–May 1997. Most (84%) of the pups observed were born in two caves separated by a short distance. Although both caves were used by females to bear the pups, preferences greatly fluctuated from season to season with no apparent trend. Reproduction occurred throughout the year with a small peak of births in October. This unusual lack of seasonality is associated with the low latitudinal location of the colony and the effect of the upwelling that provides constant food throughout the year. The neonatal sex ratio did not differ significantly from 1:1 and the estimated annual productivity ranged from 44–58 pups. Taking into account population numbers, the annual birth rates were estimated to range from 0.3 to 0.43 pups per reproductive female, an extremely low rate when compared to other pinniped populations, particularly those of a similar size. Such low rates may be either an evolutionary determined characteristic of the species or a demographic consequence of the low population density over the last few centuries. Coupled with high pup mortality rates, this may account for the observed non-recovery of the population.

The foraging behaviour of wild and captive colonies of the common mole-rat Cryptomys hottentotus hottentotus was investigated. Field studies were undertaken at Steinkopf, an arid site in the Northern Cape, South Africa. The resource biomass and the total available energy here were amongst the highest recorded for any bathyergids, but geophytes were sparse and widely distributed. The low probability of locating these widely dispersed resources should promote co-operative foraging in these mole-rats. All common geophyte species were consumed, probably because high burrowing costs favour dietary generalism. The mole-rat biomass per metre of burrow system (0.5–1.5 g.m-1) remains the lowest of any subterranean mammal. Burrow depths and diameters were positively correlated to the average mass of the mole-rats in each colony, apparently minimizing energetic costs and maximizing foraging success. Bulbs were stored in central food caches, and both field and laboratory data indicated size-based selectivity in their storage and consumption. As predicted by central place foraging theory, large bulbs were preferentially stored, and small bulbs preferentially consumed. However, factors other than energetic considerations may also influence these storage decisions. Total consumption time of bulbs was negatively correlated to animal size, and furthermore smaller bulbs were consumed more rapidly than larger ones. In addition to geophyte-storing, C. h. hottentotus also exhibited an alternative foraging strategy, termed ‘geophyte farming’, in which large bulbs were left and eaten in situ, and served as a renewable resource. Together with these foraging specializations, the evolution of sociality in mole-rats is a key factor which enables them to live in some of the most formidable habitats in Africa.

The edentulous giant anteater (Myrmecophaga tridactyla) ingests food using a slender, elongated sticky tongue which can project to a distance greater than the cranial length. A large and elongated hyoid apparatus, including a long stylohyal, epihyal, reduced ceratohyal and fused basihyal-thyrohyal fused to a partially ossified thyroid cartilage, supports the tongue. The fusion pattern and relative hyoid element sizes in adult Myrmecophaga differ from those in other xenarthran anteaters, tree and ground sloths, and armadillos. The hyoid bones have synovial joints with articular surfaces permitting great freedom of movement. A unique hyoid muscle arrangement enables Myrmecophaga to project the tongue with great speed and precise positional control. This muscle arrangement combined with an elongated secondary palate, accommodates the retracted tongue within the oropharynx without compromising the animal's ability to breathe. Maximum gape is reached at a few degrees of mandibular depression, but the oral opening is increased to 2 cm by the extreme length of the anterior facial region. Gape is further increased by medial rotation and depression of the unfused mandibular rami at the mental symphysis. This movement, even without mandibular depression, permits protraction and retraction of the elongated tongue. Mandibular rotation in lieu of depression and elevation simplifies jaw movements made by a smaller uniquely modified muscle mass over shorter distances, therefore increasing the speed with which anteaters can ingest food, and complements the extremely rapid tongue protrusion–retraction cycle.

Group dynamics of humpback dolphins Sousa chinensis inhabiting the Algoa Bay region on the south Eastern Cape coast of South Africa, were investigated by means of boat-based photo-identification surveys undertaken between May 1991 and May 1994. Groups of humpback dolphins varied in size from three to 24 animals (x = seven), with adults representing almost two-thirds of the group members. Births occurred predominantly in summer. Some females, however, may also cycle outside of the apparent summer breeding season, perhaps indicating a secondary winter season. Circumstantial evidence suggests a minimum of a 3-year calving interval. Maternal care lasts at least 3–4 years, but female–calf separation is seemingly not related to the female's next pregnancy. Humpback dolphins displayed varying degrees of residence/fidelity to Algoa Bay. Although a few individuals may possibly be classified as ‘resident’, most dolphins were infrequent visitors in the Bay and seem to be transient. The social system of humpback dolphins appears to be fluid with only casual and short-lasting affiliations. Strong bonds between individuals other than mothers and calves are uncommon. Lack of consistency in the group membership appears to be the general pattern. The weak site fidelity and possibly extensive long-range movement of the majority of dolphins may contribute to the dynamic nature of humpback dolphin groups. There is probably some form of segregation between sex and/or age classes among humpback dolphins in Eastern Cape waters. The nature and extent of this segregation, however, is not yet sufficiently understood. It is likely that the degree of site fidelity displayed by female humpback dolphins is related to their reproductive stage and increases during the nursing period. Mate-searching behaviour of male humpback dolphins is the most likely reproductive strategy of the species.

Whistle vocalizations of five odontocete cetaceans, the false killer whale P. crassidens, short-finned pilot whale G. macrorhynchus, long-finned pilot whale G. melas, white-beaked dolphin L. albirostris and Risso's dolphin G. griseus, were analysed and summarized quantitatively. Recordings were acquired from a number of locations and encounters. Significant differences were found between species and, to a lesser extent, between locations. The calls of the two pilot whale species are distinct despite their close relatedness, and similar size and morphology. This may be due to selection pressures to maintain distinctiveness. The variance was partitioned into between-species, between-location (within species) and within-location factors. For the frequency variables, variation between-species is high relative to variation between locations. Thus geographic variation is a relatively minor effect, compared to the many processes which cause interspecific differences. The within-location component includes such factors as social context, behaviour and group composition. This component is of a similar magnitude to the between-species component, indicating that whistles vary considerably with these factors. Significant between-location differences may be attributable to these confounding factors. For whistle duration, most of the variation occurred within location. There is less significant variation in duration across species compared with the frequency measures. This study highlights the need to collect samples across all potential strata whenever possible, and provides a framework for future, more comprehensive work.

The eight species of the melanogaster species subgroup of the genus Drosophila were compared to each other with respect to: (a) the electrophoretic mobility of the major chorion proteins under SDS–PAGE; (b) the overall eggshell ultrastructure. The phylogenetic tree obtained using the first criterion showed that the eight species are divided into three clusters that contain the species of the melanogaster complex (D. melanogaster, D. sechellia, D. mauritiana and D. simulans), the two species of the yakuba complex (D. yakuba and D. teissieri) and the erecta complex species (D. erecta and D. orena). This clustering is in agreement to the generally accepted phylogeny of the subgroup based on exclusive criteria. The eggshell ultrastructure of the species at the main body of the egg revealed that the phylogenetically closely related species exhibit similar eggshell structure. We conclude that the criteria applied in this study could be eventually used in groups with unknown phylogeny to trace the phylogenetic relationships of the species.

Restriction fragment length polymorphism (RFLP) was studied for six populations of the polytypic snail Neotricula aperta using seven different restriction enzymes. Samples of all three strains of N. aperta from north-eastern Thailand were examined, as well as topotypes from southern Laos and material from Kampuchea and central Laos. Genetic distances were estimated as Nei & Miller's (1990) distance ×100 (D). The samples were taken from the Mekong, Mul and Xé-Bang-Fai (XBF) rivers of the lower Mekong basin. The γ-strain of Kampuchea and southern Laos has been shown to act as intermediate host for Schistosoma mekongi. The least amount of genetic divergence was found where the α-strain was compared with other taxa (D, 2.1–3.7), and the largest values for comparisons involving samples of the XBF strain (D, 2.1–6.4). Large distances were apparent between the b-strain and all the γ-strain populations (D, 4.0–5.5). The β- and XBF-strain may represent a pair of sibling species with respect to N. aperta. The γ-strain population of north-eastern Thailand comprised two cryptic taxa which were relatively well diverged (D = 1.6). Only one of these cryptic taxa showed close affinity with other γ-strain taxa; this finding may be important in the control of Mekong schistosomiasis.

Identification of hybrids is important for the study of introgression between related species, but can be difficult when morphological differences between parental species are small. In the case of the newts Triturus vulgaris and T. helveticus, males are readily identifiable during the breeding season when secondary sexual characters are highly developed, but female dimorphism is always much less. Male hybrids with intermediate characters are therefore more likely to be detected than female ones. RAPD (random amplified polymorphic DNA) analysis of three putative newt hybrids and examples of the two parent species T. vulgaris and T. helveticus confirmed hybrid status in all three cases. The maternal parents of each hybrid were identified by amplification of mitochondrial cytochrome b and ATPase genes, including partial sequencing of the latter. One hybrid had a T. vulgaris mother while the other two had T. helveticus mothers. The PCR-based methods therefore provided a quick and simple approach for identifying both hybrid status and parentage in crosses between these two urodele species. The RAPD technique should also prove useful for the identification of larvae, which are morphologically indistinguishable in T. vulgaris and T. helveticus.

The four species of Algyroides Bibron & Bory, 1833 form part of the relatively plesiomorphic Palaearctic clade of lacertids comprising Lacerta and its allies. An estimate of phylogeny based on DNA sequence from parts of the 12S and 16S rRNA mitochondrial genes confirms the monophyly of the genus already suggested by several morphological features. The molecular data also indicates that relationships within the clade are: (A. nigropunctatus (A. moreoticus (A. fitzingeri, A. marchi))); this agrees with an estimate of phylogeny based on morphology that assumes the taxon ancestral to Alygroides was relatively robust in body form, and not strongly adapted to using crevices. Initial morphological evolution within Algyroides appears to involve adaptation to crypsis in woodland habitats. The most plesiomorphic form (A. nigropunctatus) is likely to have originally climbed extensively on tree boles and branches and there may have been two subsequent independent shifts to increased use of litter and vegetation matrices with related anatomical changes (A. moreoticus, A. fitzingeri), and one to increased use of crevices (A. marchi). Some members of Algyroides are strikingly similar in superficial morphology to particular species of the equatorial African genus Adolfus. This resemblance results from a combination of many shared primitive features plus a few independently acquired derived ones that are likely to give performance advantage in the relatively similar structural niches that these forms occupy. This study provides evidence that: (1) the use of a combination of molecular and morphological data may sometimes allow the estimation of ancestral anatomical features when these are otherwise unknown; (2) process considerations may permit a choice to be made in cases of character evolution where tree topology means that equally parsimonious alternatives exist; such decisions about character evolution may allow ecological shifts to be similarly assessed; (3) parallel evolution in ecological analogues may involve relatively few characters.

The pantropical red-footed booby Sula sula is one of the most polymorphic seabirds. In the Indian Ocean most extant colonies hold white morph adults except on Europa Island (southern Mozambique Channel), where adults are of the white-tailed brown morph and on Tromelin Island (western Indian Ocean), where one-third of the birds are of the white-tailed brown morph and two-thirds are of the white morph. On Tromelin, the morph ratio has remained constant over the last 40 years. An extinct colony (Glorieuses Islands, northern Mozambique Channel) once supported a white-tailed brown morph population. These results suggest that the colonies of the western Indian ocean do not constitute one great gene pool where exchanges occur, but are isolated at various degree from each other. Particularly, the population of Europa is the only current population of the Indian Ocean constituted almost entirely of white-tailed brown morph, suggesting that it is isolated from other nearby colonies. Possible causes of isolation are discussed in the light of oceanic features of the Mozambique Channel. Although further studies are needed to understand the adaptive significance of plumage coloration in red-footed boobies, I suggest that white-tailed brown morph at Europa may act as a defensive camouflage against kleptoparasitism by great frigatebirds Fregata minor and brown skuas Catharacta antarctica.

The morphology of the sperm storage organ (spermatheca) may influence the outcome of sperm competition in a variety of invertebrate species. Simultaneously hermaphroditic pulmonates show considerable inter- and intraspecific variation in the structure of the spermatheca. The morphological variation in the spermatheca (number of spermathecal tubules and tubule length) and the amount of sperm stored in the tubules in 115 individuals of the simultaneously hermaphroditic land snail Arianta arbustorum (L.) from six natural populations in the Eastern Alps (Gesäuse, Austria) was examined. The populations differed in snail density, therefore in the number of potential mating partners (range: 0.9–39.8 individuals/m2) and thus in the sperm competition risk. The number of spermathecal tubules ranged from two to nine. However, the six populations did not differ in either the mean number of spermathecal tubules, the length of the main tubule (range 0.9–3.4 mm), or in the cumulative length of the tubules (range 1.5–7.8 mm). The number of tubules and tubule length were not correlated with either shell height and shell breadth or with population density. The amount of sperm stored in the spermathecal tubules was estimated. Individuals from different populations did not differ in the amount of sperm stored, and the amount of sperm stored was not correlated with population density. Results indicate that the risk of sperm competition does not affect the complexity of the spermatheca (number of spermathecal tubules) in this snail. However, the possibility that individuals in high-density populations store sperm from more different mating partners than those in low-density populations remains to be examined.

The suckling behaviour of 327 piglets from 39 litters of primiparous domestic sows Sus scrofa f. domestica was analysed regarding the development of territorial suckling consistency during a 5-week suckling period. Additionally, the consistent use of a certain teat pair (1–7) during the whole suckling period was related to weight gain within the suckling period and to social dominance after weaning and mixing of the piglets. The piglets increased their suckling stability consistent with a three-parametric exponential model delivering a time-dependency that is typical for learning curves and which may be a useful methodological approach for studies on behavioural ontogeny. Thus, the development of suckling stability can be regarded as a continuous learning process. After extremely rapid learning within the first 4 days of life a moderate increase of suckling consistency with final stabilization occurred within the second week. After this time, the piglets maintained a high suckling consistency of about 95% up to the end of the observed suckling period. The anterior teats were preferred, whereas piglets suckling at the posterior teats showed a tendency to have lower weight gains and poorer dominance values. However, the lowest suckling stability (consistency) was found with piglets occupying the middle teats. The study shows that individual differences (e.g. weight gain, position in a social hierarchy) have their roots in early ontogenetic characteristics of the neonates (e.g. suckling behaviour, physical strength). The results are discussed with regard to findings and interpretations of behavioural ontogeny in pigs.