The European bitterling Rhodeus sericeus Pallas is a freshwater fish belonging to the Acheilognathinae, a subfamily that has an unusual spawning symbiosis with freshwater mussels. Female bitterling possess long ovipositors that they use to place their eggs onto the gills of a mussel through the mussels' exhalant siphon. Males fertilize the eggs by releasing sperm into the inhalant siphon of the mussel. The embryos develop inside the mussel for approximately a month, eventually leaving the mussel as actively swimming larvae. Because they use a discrete spawning site that can be readily manipulated they have recently been used in studies to understand oviposition choice with respect to mate and spawning site quality, host–parasite coevolution, alternative male mating tactics, and linking behavioural decisions with population dynamics. The current state of knowledge of bitterling reproductive ecology is reviewed and synthesized, and future directions for research on this species are proposed.

For species conservation, defining seasons according to an animal's perception and consideration of seasonal differences in its use of space is required. First, a statistical approach was used to determine seasons based on rates of movement of radio-collared caribou Rangifer tarandus caribou. Using polynomial regression, five seasons were delineated by inflection points that demarcate changes in rates of movement. Male and female caribou did not differ in timing and number of seasons. Second, the seasons so defined were used to describe the use of space in 33 caribou in north-western Ontario, Canada. Greatest rates of movement occurred during spring and early winter migration when caribou had both the largest range size and largest distance between seasonal ranges. The general direction of movement was west in spring and east early in winter, although variation occurred among caribou and years. A drop in rate of movement lasting about 3 days may indicate calving. Caribou were most dispersed and occupied the smallest seasonal range during the calving season. The animals showed strong fidelity to calving areas in contrast to the highly variable year-to-year location of winter ranges. Understanding the seasons of animal movement patterns, and applying this understanding when developing plans for forest management, may help reduce adverse effects of forest harvesting on highly mobile animals such as woodland caribou.

The variation in 10 morphometric characters and the degree of sexual dimorphism in size and shape was studied in pure and hybrid populations of smooth Triturus vulgaris and Montandon's T. montandoni newts. Multivariate analyses showed pronounced interspecific differences in both sexes. Females differed mainly in traits related to general size, whereas males differed mainly in body proportions. Triturus vulgaris males possessed a relatively longer trunk and tail. Sexual size dimorphism was much stronger in T. montandoni, the females being the larger sex. In hybrid zone populations a general correlation between morphometric traits and nuclear genotypes was found. This does not, however, fully explain the variation in size and shape. Whereas the majority of genetically identified hybrids fell into the range of morphologically pure species, many genetically pure individuals were classified as morphometric intermediates. The linear relationship between the morphometric and genetic variation suggested no strong differential selection on the molecular markers and loci responsible for morphometric differences between species. The differences in the level of sexual size and shape dimorphism, however, suggest that females of both species show dissimilar mate preferences, and thus hybrid males may experience reduced fitness resulting from lower mating success.

Caviomorph rodents (Rodentia: Caviomorpha) are an anatomically variable group with diverse ecological and morphological types, including cursorial, digging, fossorial and swimming forms. Their appendicular skeleton is rather generalized and extreme modifications or reductions in the long bones of limbs are not present. It is of special interest to evaluate functional adaptive variations of the appendicular skeleton within this group. Although much work has been devoted to study structure, function, and kinematics of legs in mammals, most studies do not consider particular functions and behaviour within different mammalian lineages. Morphometric and biomechanical studies were performed to test the relationship between adaptation and morphology of the bones of the proximal and middle limb segments in terrestrial caviomorph rodents. Fifty-four specimens belonging to 10 species with different limb adaptations and representing a wide range of body sizes were measured. Diameters and functional lengths of long bones were taken and nine functional indices were built. Humerus (HRI) and ulna (URI) robustness, humerus deltoid (SMI) and epicondyle (EI) development, olecranon proportion (IFA), femur (FRI) and tibia (TRI) robustness, and gluteal muscle insertion at femur (GI), were calculated. Only TRI and, to a lesser degree, SMI and EI, were significantly related to body mass. A functional sequence (cursorial–generalized–occasional digging–diggers) which seems to reflect an increase in force and muscular development in middle segments of the fore limb is recognized. The hind limb shows a decrease in the speed efficiency of the femur and an increase in limb robustness in the transition from cursorial to digging forms. Although overlapping of speed and force functions in the limbs is evident, functional differentiation for speed in the proximal, and force in the middle segments can be inferred.

Predictors used to calculate the body mass of extinct carnivorans often scale differently between different taxa, thus yielding body mass estimates that diverge considerably depending on which predictive equation is used. This requires the investigator to choose the ones most suitable, a procedure that is best avoided if possible. The carnivoran elbow joint is here explored with the aim of producing a single general body mass predictor that can be used over a broad range of terrestrial and arboreal carnivorans. The circumference of the distal humerus trochlea is found to be highly correlated with body mass, and trochlea circumference seems to scale similarly throughout the order Carnivora. This scaling is not as theoretically predicted by elastic similarity and is slightly higher than that predicted by geometric similarity, indicating a slight positive allometry for the latter. Some degree of differential scaling between carnivoran families and between animals of large and small size cannot be ruled out, but this result is inconclusive. A predictive model that allows mass estimations for a broad range of carnivorans is presented (a=0.601; b=2.552; r2=0.952, SEE=0.136, P<0001, n=92). Body mass for eight extinct carnivoran species are calculated and these generally conform to earlier mass predictions.

Post-metamorphic growth patterns were analysed in the tropical caecilian amphibian Ichthyophis cf. kohtaoensis (Amphibia: Gymnophiona) experimentally in captivity over 6 years. Two questions were addressed. (1) Does this Ichthyophis display sexual dimorphism for size? (2) Do ichthyophiid caecilians express an indeterminate growth pattern? Total length did not differ between sexes in the first, second or third year after metamorphosis. In the fourth, fifth and sixth years, females were significantly larger than males. The index of sexual size dimorphism increased from zero in the first year after metamorphosis to 0.104 in the sixth year. Relative growth rates of total length were different for each sex. In the first two growth seasons males grew at higher rates, while from the third growth season females grew faster than males. In general, growth rates increased from the first to the second year after metamorphosis and decreased dramatically after both sexes became mature. As all Ichthyophis in this study grew constantly throughout the first 6 years after metamorphosis, indeterminate growth probably occurs in caecilians as reported for frogs and salamanders. Additionally, growth curves for both sexes of Ichthyophis cf. kohtaoensis were estimated based on the von Bertalanffy model.

The mating system displayed by a species or population is a complex result of interactions among many factors, including social organization and resource distribution. Lekking is rare among mammals, and despite decades of research and theoretical debate, there is still little agreement concerning the socio-ecological conditions that give rise to this mating system. This study documents a lek-like mating system in a population of white-nosed coatis Nasua narica: the first such system observed in a carnivore species. Male coatis in Tikal National Park, Guatemala, aggregated around mobile bands of females during the mating season. The males displayed from the forest canopy above the bands, and females ascended to a male's perch when they were ready to mate. Males did not provide resources or parental care. Thus, the mating system, which differed from classic lekking only in the lack of an arena, can be best described as mobile lekking. Male coatis apparently resort to self-advertisement when the large size and large home ranges of female groups make defence of females or resources impractical.

Large-scale anthropogenic habitat degradation is taking place in the Negev Desert and such degradation is considered to be the primary cause of population decline in many bat species. A study of bat community structure in the central Negev Desert Highlands was undertaken to examine habitat associations, activity patterns and the distribution of bats in relation to landscape structure. During 1999 and 2000, mist-nets and bat detectors were used to capture bats and to monitor their presence in natural and artificial sites. In total, 12 species of insectivorous bats were found. Communities of insectivorous bats were divided into three guilds based on foraging space: open space foragers, background-cluttered space foragers, and highly cluttered space foragers. Bats of the background-cluttered space guild foraged over a variety of habitats while bats from the other guilds were more restricted with regard to their foraging spaces. In both years, season had a significant effect on bat activity. Despite there being significantly more bat activity in artificial sites than in natural sites, bat species richness was least in the artificial sites. For most species of desert-dwelling bats, areas that are typified by dense vegetation cover and have a perennial water source are of primary importance.

Acoustic monitoring and radio-tracking were used to study the nocturnal activity of adult female Indiana bats Myotis sodalis at a maternity site in Michigan, U.S.A. Pregnant bats did not use the day roost at night, but lactating females returned 2–4 times/night for 32±7 (SE) min/visit, presumably to feed their young. Both pregnant and lactating females night roosted as solitary individuals in trees within their foraging areas; night roosting occurred 0–6 times/night for 14±1 min each time. Bats foraged for most of the night, with the total duration of flight equalling 375±16 min/night. The bats used 13 different foraging areas that were located 0.5–4.2 km from the day roost. Bats did not fly over open fields but travelled along wooded corridors, even though such behaviour increased commuting distance by 55±11%. Current models of habitat suitability for this endangered species should be modified, taking into account the use of wooded commuting corridors and the large home range of these bats.

This study was an investigation of the diet and of prey selection by a population of African wild dogs Lycaon pictus in the Savé Valley Conservancy (SVC) in the south-east lowveld of Zimbabwe. The diet of the dogs, based on the number of kills for each species located, consisted almost entirely of impala Aepyceras melampus (74%) and kudu Tragelaphus strepsiceros (22%), the two most abundant medium-sized antelope in the area. The level of selection for different prey classes killed by the wild dogs was investigated and it was found that the wild dogs: (1) exhibited strong selection for a number of prey classes on a seasonal basis; (2) selected kudu throughout the year but showed little selection between the other prey species; (3) selected the young of both impala and kudu and selected males at times of the rut. Bone marrow analysis showed that prey killed by the wild dogs on SVC were in poorer condition than unselectively culled individuals suggesting the selection of the weaker individuals in the prey populations.