There is no consensus on the question of whether or not free-living protist species have biogeographies, with the strongest disagreement coming from advocates of the hypothesis that the extraordinary abundance of protists drives their ubiquitous dispersal. If the probability of a species being ubiquitous is a function of its absolute global abundance, then the species that are least likely to be ubiquitous are those with relatively small global populations, i.e. the largest species. Among the free-living ciliated protozoa, a prime candidate for such an organism must be the large (~1200 μm long), unmistakable, fragile, non-encysting karyorelictid Loxodes rex. This ciliate was known only from fresh waters in tropical Africa and it was long considered to be a rare example of an endemic ciliate. Here it is reported that Loxodes rex is thriving in a pond in Thailand. The status of other alleged endemic ciliate species is discussed.

This paper presents basic demographic parameters of African elephants (Loxodonta africana) living in and around Amboseli National Park, Kenya. The study was conducted from 1972 to the present and results are based on the histories of 1778 individually known elephants. From 1972 to 1978, the Amboseli elephant population declined and then increased steadily from 1979 to the present. Births occurred throughout the year but over 80% occurred between November and May. Birth rate varied from year to year with a pattern of peaks and troughs at 4- to 5-year intervals. The birth sex ratio did not differ significantly from 1:1. Mean age at first birth was 14.1 years, determined from a sample of 546 known-age females. Mean birth interval (n = 732) was 4.5 years for 255 females. Fecundity and calf survival varied by age of the females. Mortality fluctuated from year to year. Sex-specific mortality rates were consistently higher for males than females at all ages.

Two orb-web spider species, one diurnal and one nocturnal, were studied and shown to be highly flexible in their behaviour. Flexibility is discussed in relation to improving capture success and avoiding predation. Although earlier studies have revealed that spiders modify web design and web orientation according to light and wind direction, here we show that orb-web spiders can further respond to light and wind direction by choosing a side of the web to reside on. The diurnal species, Argiope keyserlingi, tended to orient its dorsal side into vegetation gaps and towards light, whereas the nocturnal species, Larinioides sclopetarius, tended to expose its dorsal side into the oncoming wind. While orientation on the web had little affect on prey capture success, in A. keyserlingi, orientation into vegetation gaps may reduce attacks by praying mantids which approach the spiders by walking along the vegetation surrounding the web. In contrast, exposing the dorsal side into the wind may increase stability on the web for L. sclopetarius, preventing the spiders from being dislodged from the webs by strong gusty wind.

The reproductive tracts of 152 female Atlantic walruses Odobenus rosmarus rosmarus were analysed. The material was collected between 19 January and 19 November in 1977–78 (n = 44) and 1988–91 (n = 108) from the subsistence hunt by Inuit in north-west Greenland (i.e. in the eastern parts of the North Water polynya in northern Baffin Bay). Seventy-six per cent of the walruses were sexually mature. Oestrus females (n = 23) were found between 19 January and 25 June. Based upon ovarian anatomy, females may ovulate several times during oestrus but ovarian anatomy could not be used to determine if an individual was pregnant. The youngest female that had given birth was 5 years old, indicating that some female Atlantic walruses become sexually mature at 4 years of age. The oldest immature female was 8 years old, and the oldest animal that ovulated for the first time was 11 years. Age-related growth in the reproductive tract indicated that sexual maturity was reached between 6 and 8 years of age. Based on reproductive history of 93 individuals (0–12 years old) the average age of attainment of sexual maturity (i.e. first ovulation) was 6.1 years (95% CI: 5.2–7.1 years). Of 81 mature females collected during May–November, 34.6% were pregnant, 43.2% postpartum and 22.2% inactive. These proportions did not differ from a model assuming a triennial reproductive cycle. Growth in foetal length and mass with time indicated that implantation occurred between 29 June and 11 July or between 26 June and 5 July, respectively. Mean birth date based on observations of 28 newborns was 20 June (range 4 February–11 November).

Group pattern and social segregation of the sexually size dimorphic Przewalski's gazelle Procapra przewalskii were studied for 7 years in the Qinghai Province, China. The main social units were: female groups; male groups; mixed groups. Mixed groups were the largest and most visible, whereas adult male groups were small and of similar size. The group size of the gazelle varied during different seasons (P < 0.002) and the type of social groups (P < 0.001). Mixed-sex groups were larger than female groups or male groups across all the seasons (P < 0.008). Adult males and females were mainly in separate groups except during the rut. Groups of adult females were the most common social unit in Przewalski's gazelle, followed in frequency by adult male groups and mixed groups. From late June to late August, social separation was most pronounced. From late October to mid-September, social segregation was not pronounced. Social segregation showed significant seasonal differences in Przewalski's gazelle (P < 0.004), especially between the rut and other seasons (P < 0.008). The pattern of social segregation of groups and behaviours observed imply that social factors play important roles in social segregation and group formation.

Phenotypic evolutionary rates are reported for cranial characters of eight species of large-bodied Neotropical marsupials: Didelphis aurita, D. marsupialis, D. albiventris, Philander opossum, P. frenata, Lutreolina crassicaudata, Chironectes minimus, and Metachirus nudicaudatus. These rates were found to be lower than expected if cranial diversification in these opossums had occurred by mutation and genetic drift only, and it is clear that a greater diversification was prevented. As all parameters used in estimating rates were very conservative, the conclusion that stabilizing selection has predominated during the evolution of the skull of large-bodied opossums is fairly robust. We also show that directional selection sustained for 150 generations (158 years) or less is capable of producing differences of the same magnitudes as those found between various pairs of species. Therefore, we conclude that even where a particular differentiation has been caused by directional selection, neutral rate tests are unlikely to infer it. This is because following a morphological shift, stabilizing selection will progressively erase evidences of directional selection.

In lowland England, badgers Meles meles form social groups of up to 30 individuals. They share a main den (sett) and a core feeding range, but largely forage alone. Faeces are deposited in discrete hinterland and border ‘latrines’. Border latrines are shared with neighbouring groups. We demonstrate that there is a highly significant tendency for neighbouring groups to place a similar quantity of faeces at shared latrines. There are also significant tendencies to place more faeces in boundary latrines close to the sett, and for reduced separation of latrines close to the sett. We also demonstrate that badgers tend to defecate most frequently on the boundary closest to their current feeding site. These observations are consistent with the hypothesis that faeces at border latrines are used to promote range exclusion. We propose that faecal volume represents a reliable signal of the encounter likelihood and/or foraging pressure of badgers along a particular border. According to the ‘active territorial defence’ hypothesis, this indicates a stand-off position in terms of each group's resource holding potential by signalling encounter likelihood across the boundary. By the ‘passive range exclusion’ hypothesis, this border is an isopleth (equal contour) of resource depletion between groups, and crossing over such a contour deep into a neighbouring range reduces foraging efficiency. By either hypothesis, the matched faecal volume and sett proximity effects suggest a simple mechanism that is capable of allowing reliable information to be passed by individuals between adjacent sectors of neighbouring territories to deter intrusion. This is a ‘bottom–up’ process of inter-dependent, parallel, individual responses, which is capable of generating the emergent complexity of co-ordinated group ranges without central control.

One of the hypotheses proposed to account for why badgers Meles meles are highly social in the U.K., the resource dispersion hypothesis, is that patchy resources are unpredictably dispersed in the environment and therefore must be shared, but that these patches are rich enough, when available, to support several badgers at any one time. Previous empiricists in our study site at Wytham Woods calculated that single patches could be rich enough to support 30 badgers in a night. The sustained increase in population density in Wytham Woods suggests that food was not limiting and territories were below capacity, and therefore that feeding competition was relatively low. Low feeding competition would predict an absence of dimorphism in trophic apparatus between the sexes. Contrary to this, significant sexual dimorphism was found, after removing effects resulting from body size allometry, in canine cross-section length, width (both P < 0.0001) and skull breadth (P < 0.001). The differences in canine dimensions were still significant when allometry of both body length and skull breadth are accounted for statistically (P < 0.0001). It is therefore suggested that feeding competition may not necessarily be low, which would have implications for understanding the costs of social behaviour. Alternative explanations involving sexual selection and phylogenetic inertia are discussed.

This study examined the foraging locations of lactating female and pre-breeding adult male South American sea lions Otaria flavescens in the Patagonian continental shelf, south-west Atlantic ocean. Research on females included the diving pattern, and was conducted during the 1994–98 breeding seasons in five northern and central Patagonian rookeries. Twenty females were satellite-tracked using the Argos system and yielded 1558 locations at sea. Satellite transmitters were also deployed on two adult males tracked for a total of 94 days (n = 364 locations) before the onset of the 1999 breeding season. Foraging trips for both sexes were confined to the temperate waters of the Patagonian continental shelf although males travelled greater distances than females, and arrived close (c. 80 km) to the edge of the shelf. Females from the same rookery dispersed widely and locations at sea often overlapped. Individual differences were apparent between coastal and pelagic animals. Trips lasted a mean of 3.4 days (sd = 1.3, n = 115 trips). Mean travel distance per trip was 206 km (sd = 117 km, maximum 864 km, n = 115 trips). Females reached further distances by travelling faster rather than by extending the duration of trips. Consistent with the shallow continental shelf, 65% of 75 087 dives recorded for nine animals were in the range of 2–30 m. Males alternated periods on the coast with trips to sea lasting a mean of 5.7 days (sd = 3.0, n = 8 trips). Mean travel distance exceeded 591 km (1 sd = 301 km, n = 8 trips). Results are consistent with sex differences reported from diet studies. Locations overlap with the summer operation of shelf fisheries targeting species that are also part of the sea lion diet.

A new representative of the thus far monotypic, Bermudan aselloid family Atlantasellidae is described from the freshwater layers of two coastal sinkholes on the south-west Dominican Republic, Hispaniola. Atlantasellus dominicanus sp. nov. is extraordinary among isopods in retaining a remnant of the exopod on one of its pereiopods; no other isopod is known to express a schizopodous condition of thoracic limbs. The locomotory behaviour, body volvation habits, and apparent specificity of the new taxon for life on submerged decaying wood in cave waters are described. Analysis of palaeogeographic and ecological evidence supports the interpretation of the Atlantasellidae as a thalassoid lineage, contrary to previous phylogenetically supported assumptions considering them to be an ancient, freshwater lineage.

Within the clariids (air-breathing catfish), a complete range of fusiform to anguilliform species can be observed. This study deals with the cranial morphology of Channallabes apus, an extreme anguilliform (eel-like) species, compared to the anguilliform Gymnallabes typus and the more fusiform Clarias gariepinus. The overall morphology of the head of Channallabes apus shows a hypertrophied adductor mandibulae complex, with the corresponding substantial narrowing of the neurocranium, seen in the frontals, the sphenotics, the pterotics and the posttemporo-supracleithra, as well as the reduction and displacement of the eyes and some canal bones, such as the infraorbitals and the suprapreopercles. The presence of a hypertrophied muscle complex possibly indicates that a more powerful bite may occur. This implies that adaptations can be expected in several parts of the skull. On the lower jaw of C. apus a higher coronoid process is found, and on the suspensorium, two sets of three processes are present on the hyomandibular bone, indicating a stronger connection to the neurocranium. Several of the observed features, such as the elongation of the body, the reduction of the eyes, the increase in vertebrae number, limblessness and the increasing rigidity of the skull, may also be related to a process of miniaturization.

The population density and nesting behaviour of gorillas (Gorilla gorilla gorilla) was studied in the Ngotto forest, Central African Republic. We carried out a nest count along 94 km of transects. Also, the herbaceous vegetation of the understory was quantified and we attempted to assess the decay rate of nest sites. A total of 145 gorilla nests in 27 nest sites was found. We found 82.1% of gorilla nests > 2 m above ground. There was a significant correlation between the height of nests and the diameter of trees with nests. The density was estimated at 0.34–0.40 weaned gorillas per km2 depending on the value of nest site decay rate used. The herbaceous vegetation was scarce in the study site (42 out of 50 quadrats had no herbaceous stems). Compared with the gorilla population of the nearby Dzanga-Sangha forest, the population density of gorillas at Ngotto was lower but the proportion of nests found above ground was much higher. These differences are discussed and we suggest that they were the result of the scarcity of herbaceous vegetation in the Ngotto forest.

We studied the effect of morphological variation and basking posture on thermal characteristics in the speckled wood butterfly Pararge aegeria (L.). The process of heating and cooling in relation to wing type (descaled, darkened and original wing colour) and size was examined using dummies (i.e. dried butterflies). Size (measured as wing length) and ambient temperature have a joint influence on body temperature: large butterflies heat up more slowly than small ones, but with increasing ambient temperature the difference with size became smaller and even changed since large individuals heated up faster under warm ambient conditions. Surprisingly, darkening wings had no overall effect on thermal characteristics, but this may be an artefact of the manipulation as supported by the results of the absorption measurements. Normal butterflies reached a higher equilibrium thoracic temperature than descaled butterflies probably because wings without scales absorb less radiation. Finally, butterflies with fully spread wings reached higher thoracic temperature and had faster cooling rates compared to butterflies with half-opened wings. Implications of the results for the relation between morphology and behaviour of speckled wood butterflies in their natural habitat are discussed.

This paper reports upon the use of nest boxes in coniferous woodland by the red squirrel Sciurus vulgaris, great tit Parus major and the jackdaw Corvus monedula over a 6-year period from 1994 to 1999. Initially 30 nest boxes were erected with eight additional boxes being put up in 1995. In the period 1994 to 1997, red squirrels were found to use nest boxes regularly as nesting and breeding sites (7.8 ± 1.0 se litters found annually). Box use was greatest in the summer and autumn months (70% of boxes being used at least once) and declined through the winter (50%) into the spring (45%). The presence of great tit clutches and broods in the spring did not prevent red squirrels from occupying boxes. Only 28% (n = 12) of all the recorded great tit clutches produced fledgling young in 1994 to 1997 and red squirrels were found to have consumed some of the chicks and eggs. The establishment of a jackdaw colony within the woodland led to 86% of the nest boxes being used by the birds in the spring of 1999. Red squirrel occupation of boxes in the spring declined to 7% and only three litters were recorded that year. The study showed that the jackdaw has the capacity to dominate nest boxes during the spring months despite the high density of red squirrels within the reserve.

The study focuses on the differences between large and small forms of a rotifer species, Macrotrachela quadricornifera (Rotifera, Bdelloidea), by reviewing the literature and adding further morphological differences. Evidence from life-history traits, growth patterns and trophi (hard structures of the specialized rotifer pharynx) morphology suggests that the large and small forms of M. quadricornifera should not be considered the same species. Macrotrachela vanoyei Schepens, 1954 is re-established as a good species, differing from M. quadricornifera in the smaller size of body, egg and trophi, as well as the number of proximal and distal teeth on the trophi.

Logarithmic transformation is used to transform multiplicative phenomena to a linear, additive scale. Some workers recommend the transformation x′ = log x + 1 when observed values are equal to zero. However, when working with morphometric data, this transformation is inappropriate because it arbitrarily changes the nature of the relationship between body parts. To illustrate this point, this contribution re-analyses a data set from the recent literature.