Does rumen–reticulum capacity correlate with body size or age in black-tailed deer?

To accommodate an increased food intake with greater body size, rumen–reticulum capacity must become larger to allow heavier digesta loads. Recently, digesta load was found to correlate with age more strongly than body size. It was suggested that older animals had compromised mastication efficiency due to tooth wear and compensated for larger particles by increasing rumen–reticulum capacity to extend retention time. Herein, we constructed models and used Akaike Information Criteria corrected for small sample size to determine if digesta load was related with age or body weight in 80 female and 105 male black-tailed deer (Odocoileus hemionus columbianus). We also assessed if the presence of fetuses influenced relationships in females. Females were collected in spring, 1985–1988, and males were collected in autumn, 1980, 1982–1984, and 1988, from Hopland Research and Extension Center, Mendocino County, California. Digesta loads, fetuses, and carcasses were weighed, and animal ages were estimated. Digesta load was related to age in females and body weight in males. Our study shows that body size and age-related factors may both influence rumen–reticulum capacity.     

Temporal changes in the reproductive population structures and males’ secondary sexual character of the hermit crab <Emphasis Type="Italic">Diogenes nitidimanus</Emphasis>

We investigated the reproductive ecology of D. nitidimanus in the Waka-River estuary with special reference to temporal change in the relative size of chelae length for males, i.e., secondary sexual character. Ovigerous females were observed from April to October, peaking in June–July with over 90% of females being ovigerous. Adult female carapace size ranged from 3.5 to 8.5 mm, but with the majority of females falling between 5–6 mm. Male carapace length was more evenly distributed between 3.5 and 10 mm. Juvenile settlement occurred mostly in July, during which time the frequency of both large females (over 6.5 mm in carapace length) and large males (over 8.5 mm in carapace length) clearly decreased. The carapace length of precopulatory-guarded females varied from 4.8 to 8.0 mm, while guarding males were almost over 7 mm and always larger than their paired females. The relative growth of the major chelae differed significantly between small and large males during the early months of the year, including the reproductive peak months (April–June). During these early months, large males had relatively larger chelae for their body size than did small crabs. This difference, however, was not evident later in the year (July–September). Large males may grow their chelae relatively long in the early months in order to take advantage of the mating opportunities during April–June. This is the first report in animals, to our knowledge, that relative size of the secondary sexual character for males temporarily change during a single reproductive season.     

Non-invasive monitoring of adrenocortical activity in free-ranging fallow deer (<Emphasis Type="Italic">Dama dama</Emphasis> L.)

Measurement of faecal glucocorticoid metabolites is increasingly used as a non-invasive tool to examine disturbances in various domestic and wild animals. Because measurements of faecal glucocorticoid metabolites has previously never been reported in fallow deer, we determined 11,17-dioxoandrostanes (11,17-DOA), a group of cortisol metabolites, in the faeces of four fallow deer yearlings after an adrenocorticotropic hormone (ACTH) challenge or control saline injection by an 11-oxoaetiocholanolone enzyme immunoassay (EIA), to validate a method. A 2.9- to 4.3-fold increase in measured cortisol metabolites in challenged animals after approximately 22 h demonstrated the suitability of this group-specific EIA to monitor adrenocortical activity in respective deer species. To determine faecal cortisol metabolites in fallow deer from a Mediterranean habitat, we collected samples during a 1-year study at Veliki Brijuni Island. The study confirmed seasonal pattern of cortisol release in fallow deer. Higher 11,17-DOA concentrations (median; min–max) were determined for November (99; 50–2,035), March (112; 25–315) and May (92; 40–196 ng/g faeces). Significantly lower concentrations were measured during July (30; 10–195 ng/g faeces). This study indicates that the analysis of faecal glucocorticoid metabolites is a valuable non-invasive technique for monitoring adrenocortical activity in fallow deer. This, together with information about the seasonal pattern of glucocorticoid excretion, could help to improve fallow deer management and welfare, especially in the case of farmed and park animals.     

Sexual dimorphism in <Emphasis Type="Italic">Sebastes owstoni</Emphasis> (Scorpaenidae) from the Sea of Japan

Morphological and genetic differences between red and yellow morphotypes of Sebastes owstoni were investigated, utilizing 277 males [84.0–194.3 mm in standard length (SL)] and 542 females (92.3–251.5 mm SL) from the Sea of Japan. All males smaller than 120 mm SL were characterized by red body color. The frequency of specimens with yellow body color thereafter increased gradually with SL, all specimens larger than 170 mm SL being yellow. The specimens with yellow body color were observed throughout the year. All females smaller than 170 mm SL were characterized by red body color, the frequency of specimens with yellow body color tending to slightly increase with SL. However, most females had red body color, except for 16 specimens (177.7–241.5 mm SL) that were yellow, growth-related color change from red to yellow being uncommon. Morphological analysis of 49 males (107.6–193.3 mm SL) and 68 females (108.7–241.5 mm SL) showed the head length, orbit diameter, lower jaw length, and predorsal length to be relatively greater, but the distance between the pelvic and anal fins less, in males. A discriminant analysis using Mahalanobis distances resulted in 100% correct assignment of specimens to sex, regardless of SL and body color. In addition, no genetic differences were apparent between red and yellow individuals in mitochondrial DNA sequence analyses from the threonine tRNA to the first half of the control region (498 bp). Accordingly, the differences in body color, maximum size, and the five morphometric characters listed above were considered to represent sexual dimorphism. That evidenced by body color was considered to appear after that shown by morphometric characters, some exceptions in the former occurring in females. This is the first report of permanent sexual dimorphism in body color in Sebastes.     

Attachment site selection of ticks on roe deer, <Emphasis Type="Italic">Capreolus capreolus</Emphasis>

The spatio-temporal attachment site patterns of ticks feeding on their hosts can be of significance if co-feeding transmission (i.e. from tick to tick without a systemic infection of the host) of pathogens affects the persistence of a given disease. Using tick infestation data on roe deer, we analysed preferred attachment sites and niche width of Ixodes ticks (larvae, nymphs, males, females) and investigated the degree of inter- and intrastadial aggregation. The different development stages showed rather consistent attachment site patterns and relative narrow feeding site niches. Larvae were mostly found on the head and on the front legs of roe deer, nymphs reached highest densities on the head and highest adult densities were found on the neck of roe deer. The tick stages feeding (larvae, nymphs, females) on roe deer showed high degrees of intrastadial spatial aggregation, whereas males did not. Male ticks showed large feeding site overlap with female ticks. Feeding site overlap between larval-female and larval-nymphal ticks did occur especially during the months May–August on the head and front legs of roe deer and might allow pathogen transmission via co-feeding. Tick density, niche width and niche overlap on roe deer are mainly affected by seasonality, reflecting seasonal activity and abundance patterns of ticks. Since different tick development stages occur spatially and temporally clustered on roe deer, transmission experiments of tick-borne pathogens are urgently needed.     

Population dynamics and spatial behaviour of <Emphasis Type="Italic">Microtus tatricus</Emphasis> (Arvicolinae,Rodentia)

The population dynamics of the Tatra vole Microtus tatricus (Kratochvíl, 1952) (Arvicolinae, Rodentia) was monitored as part of a long-term study (1996–2008) of demography of small mammals conducted in Western Tatra Mountains—Roháče, Slovakia. We observed low abundance and population densities and a balanced sex ratio but slightly more frequent captures of females. Reproductively active Tatra voles were significantly larger and heavier than reproductively inactive voles. Reproduction in both sexes tended to begin in early spring, and females moved less than males. Individuals start to reproduce after overwintering. Spatial characteristics differed between sexes, with home range size, distance travelled, and observed range length being non-significantly greater in males than in females, suggesting greater male mobility. Females remained longer on the site than did males. Mature individuals of both sexes exhibited territoriality during the peak of breeding season in spring. Home range overlap occurred more often within females, and mainly in summer and autumn.     

Olfactory communication and counter-marking in brown brocket deer <Emphasis Type="Italic">Mazama gouazoubira</Emphasis>

Scent marking by defecation and urination in numerous small latrines may be related to resource defence in brown brocket deer (Mazama gouazoubira). Both males and females seem to be territorial, and both contribute to latrines where their ranges overlap. Latrines could thus potentially function as centres of information exchange and intrasexual competition. Counter-marking occurs when animals respond to invaders' marks with a greater number of marks. The objectives of this experimental study were to determine whether brown brocket deer distinguish dung of presumed invaders from their own and whether they counter-mark such faecal deposits. Two samples of dung (from unknown males or females and the experimental animal) were introduced near the latrines of 21 captive deer (13 males and eight females), and we observed their responses, including investigative (sniffing) and marking (urination and defecation) behaviours. Males investigated the introduced dung and their own latrine significantly more when the dung was from an unknown male than when it was their own. Females investigated unknown female dung significantly more than their own. Males counter-marked the introduced dung and their latrine significantly more when the dung was from an unknown male than when it was their own. Males marked with a shorter latency and at a greater frequency than females. Our data indicated that males counter-mark most intensively dung from male ‘intruders’ which may be related to intrasexual competition and resource defence. Females showed a non-significant tendency to counter-mark same sex intruders.     

Growth and Development in Wild Owl Monkeys (<Emphasis Type="Italic">Aotus azarai</Emphasis>) of Argentina

Life history predicts that in sexually dimorphic species in which males are the larger sex, males should reach sexual maturity later than females (or vice versa if females are the larger sex). The corresponding prediction that in sexually monomorphic species maturational rates will differ little between the sexes has rarely been tested. We report here sex differences in growth and development to adulthood for 70 female and 69 male wild owl monkeys (Aotus azarai). In addition, using evidence from natal dispersal and first reproduction (mean: 74 mo) for 7 individuals of known age, we assigned ages to categories: infant, 0–6 mo; juvenile, 6.1–24 mo; subadult, 24.1–48 mo; adult >48 mo. We compared von Bertalanffy growth curves and growth rates derived from linear piecewise regressions for juvenile and subadult females and males. Growth rates did not differ between the sexes, although juvenile females were slightly longer than males. Females reached maximum maxillary canine height at ca. 2 yr, about a year earlier than males, and females’ maxillary canines were shorter than males’. Thus apart from canine eruption and possibly crown–rump length, the development of Azara’s owl monkeys conforms to the prediction by life history that in monomorphic species the sexes should develop at similar paces.     

Factors affecting daily ranges of red deer<Emphasis Type="Italic">Cervus elaphus</Emphasis> in Białowieża Primeval Forest,Poland

Daily ranges of 19 (6 males, 13 females) adult red deerCervus elaphus Linnaeus, 1758 were studied using 24-h tracking sessions in Białowieża Primeval Forest (BPF), Poland, from 2001 to 2004. Overall, size of mean (± SE) daily ranges was larger for males (1.22 ± 0.10 km²) than females (1.00 ± 0.09 km²), although the difference was not significant. Similarly, mean daily ranges were 6–46% larger for males than females in each season, although there were no statistical differences in mean daily ranges among seasons for each sex. Abiotic factors, especially temperature, significantly affected daily ranges of females, but not males, suggesting sexual differences in response to weather variables. On a daily basis, males used 3% of their annual home range, whereas females used 12% of their annual home range, indicating females used their annual home ranges more intensely than males. Consecutive daily ranges overlapped little for each sex. Daily ranges of red deer in BPF were considerably larger than previously reported in Europe, suggesting factors unique to BPF also influenced size of daily ranges.     

Space use and territoriality of wolverines (<Emphasis Type="Italic">Gulo gulo</Emphasis>) in northern Scandinavia

Space use and territoriality influence population structure and dynamics and is therefore an important aspect in understanding the ecology of animals. We investigated spatial and temporal space use of wolverines (Gulo gulo) in northern Scandinavia. We estimated home ranges of 24 radio-marked individuals (17 females and seven males). Male home ranges (mean 669 km²; SE = 211) were significantly larger than female home ranges (mean 170 km²; Wilcoxon–Mann–Whitney; P = 0.001) and encompassed or included parts of up to five different females. Home range sizes of reproducing (170 km²; SE = 51) and barren (171 km²; SE = 63) adult females did not differ. Wolverines in Scandinavia exhibit intrasexual territoriality, with male home ranges totally exclusive and female home ranges either exclusive or with little home range overlap. Overlap between wolverine territories is most likely explained by intrasexual tolerance and kinship.     

Morphometric variation of the skull during postnatal development in the Lowland European bisonBison bonasus bonasus

We studied the variation of linear measurements and skull capacity in Lowland European bisonBison bonasus bonasus (Linnaeus, 1758) during postnatal development, and the dependencies of the parameters in relation to sex, age, and body mass of the animals. Material consisted of 599 bison skulls (310 males and 289 females), within the age range of 1 month to 21 years (males) and to 27 years (females). In the group of calves to 1 year old, no sex connected differences in skull measurements were observed, whereas the skull capacity in older calves was significantly larger (0.01>p>0.001) in males than in females. From the third year of life, most skull measurements display characteristics of sexual dimorphism. Skull development in both sexes is most intensive during the first three years of life, and slows from the age of 5. In older individuals of both sexes (≥ 6 years), orbital breadth continues growing and, in females, breadth of splanchnocranium continues increasing. Growth in a bison’s skull capacity is most intensive up to the third year of life and slows from the age of 5. During postnatal development, a bison skull grows proportionally except the neurocranium, which grows slightly slower in comparison with basal length and its development finishes earlier than that of splanchnocranium. In ontogenesis, a bison skull grows much slower compared to body mass. In relation to body mass, skull capacity and the height of neurocranium grow most slowly while orbital breadth grows most intensively. The results obtained were compared with data on skull sizes of bison born in 1930–1950 and bred in captivity and with skulls of the American bisonBison bison. Inbreeding is probably responsible for some types of phenotypic abnormalities in the skull which appear in modern European bison.     

Space use of common genets<Emphasis Type="Italic">Genetta genetta</Emphasis> in a Mediterranean habitat of northeastern Spain: differences between sexes and seasons

The seasonal home range size and spatial relationships of 16 adult genetsGenetta genetta Linnaeus, 1758 (6 males and 10 females) were estimated in a Mediterranean habitat of northeastern Spain. Genets minimum density was estimated as 0.98/km². Mean annual home range was 113.1 ha in males and of 72.0 ha in females. Males had larger home ranges than females in all seasons, but differences were only significant in winter. Home range size changed seasonally and showed a similar pattern in both sexes, with lower values in summer (males — 41.2 ha, females — 29.0 ha) and maximum ones in spring (males — 78.8 ha, females — 56.1 ha). Animals displayed spatial fidelity throughout the year. Core areas (MCP50) represented 27% and 19% of total home range size for males and females, respectively. Resting home ranges (based on locations of inactive animals) were 9 times lower than overall home range size. Individuals of the same sex overlapped less than individuals of different sexes, especially with regard to core areas, which showed almost no overlap. The results obtained suggest that (1) different factors are likely to affect the space use of genets, such as body mass, food abundance and reproductive cycle; (2) genets use space in a heterogeneous way, with areas of greater activity than others within their home range; (3) there was intrasexual segregation with regard to space use.     

Exclusive core areas and intrasexual territoriality in Eurasian red squirrels (<Emphasis Type="Italic">Sciurus vulgaris</Emphasis>) revealed by incremental cluster polygon analysis

When animal home ranges overlap extensively in species lacking overt territorial behaviours, identifying exclusive core areas within individual ranges can be difficult. By analysing the size and overlap of successively smaller core areas among individual Eurasian red squirrels (Sciurus vulgaris), we determined exclusive areas within the home ranges of resident males and females. Possible effects of habitat composition and food supplies were explored by monitoring squirrels in different conifer forests and during years with low and high tree seed production. Using outlier-exclusive cores (OEC) revealed that the total ranges consisted of large sally zones (on average, 35% of the total minimum convex polygon [MCP] range) around home ranges with multi-nucleate cores. The mean OEC home range size did not differ between the sexes but was larger with poor food availability. Home ranges (99% incremental cluster polygons [ICP]) overlapped extensively between sexes (average overlap high food–low food: males by females 21–40%, females by males 43–45%) and among males (males by males 26–44%), while intrasexual overlap among females was low (9–10%). The overlap of inner cores among females rapidly approached zero, suggesting the intrasexual territoriality of 75% core areas. This was not the case among male squirrels, for which intrasexual overlap averaged only 4% at 50% but 18% at 75% core areas. Even the smallest inner cores had some degree of intersexual overlap, indicating that complete territoriality did not occur in this species. Female home ranges were more strongly affected by annual fluctuations in food supplies than male ranges. Females reduced the size of their food-based intrasexual territories when food availability increases. Males probably benefit from using larger home ranges and core areas, which overlap with the ranges of several females, by increasing their probability of successful mating.     

Effects of population structure and density on calf sex ratio in red deer (<Emphasis Type="Italic">Cervus elaphus</Emphasis>)—implications for management

There is ongoing interest to assess what factors affect offspring sex ratio, especially in ungulates. Wildlife managers might be interested in influencing this sex ratio for two reasons: either in order to limit population growth more effectively by reducing the proportion of females born or to increase revenues by a higher proportion of trophy bearing males in the population. While previous studies mostly focused on how maternal traits affect offspring sex ratio, we included here also male traits in our analysis. We achieved this by investigating data from 30 areas covering entire Lower Austria, collected over the past 12 years from both hunted red deer and those killed in road accidents. We focused our analyses on parameters that can be easily assessed by managers on the population and individual level, i.e. the numbers of animals culled in different age/sex classes and their body mass. We found that the proportion of females among calves increased with population density. Furthermore, we found that calf sex ratio (i.e. the proportion males among calves aged between 2 and 7 months) increased with increasing proportions of adult females and males older than 10 years, independent of the density effect. We conclude that wildlife managers interested in the effective reduction of red deer abundance and/or increasing the proportion of males among offspring should select a culling regime leading to a low population density dominated by adult, prime-aged females and males. This can be achieved by over-proportional removal of young females and warranting that a high number of strong males reach an age of at least 10 years.     

Variation in cohort mandible size as an index of roe deer (Capredus capreolus) densities and population trends

This paper examines the effects of increasing population density on the skeletal development of roe deer as indexed by variation in the size of the mandible. We tested for density-dependence in total jaw length and minimum diastema height among cohorts in a single, intensively studied population in France. A strong relationship of average adult jaw length of both males and females with deer density in the year of birth of a given cohort was observed, and presumably reflects inadequate nutrition of juveniles at high population density. No such relationship was observed for the minimum diastema height which remained constant over the range of densities studied. This relationship was exploited to investigate population trends of roe deer in Britain. In nine populations, where equivalent data were available for between 16 and 28 separate cohorts, a consistent pattern of variation in cohort jaw size was observed, with a decrease in average total length, but not diastema height, towards the present. This trend is discussed in relation to changes in habitat structure in the coniferous forests of Britain. The utility of cohort jaw length as a management tool to index population trends of roe deer is highlighted.     

Size composition and reproductive biology of the ornate jobfish <Emphasis Type="Italic">Pristipomoides argyrogrammicus</Emphasis> (Lutjanidae) off Ishigaki Island,Okinawa

The ornate jobfish Pristipomoides argyrogrammicus is an important lutjanid species for fisheries in the Okinawan region of Japan. The present study estimated the size composition and reproduction of this species in the waters around Ishigaki Island, Okinawa Prefecture. The length–frequency distribution indicated that males grow larger than females. The fork length (FL; mm)–whole body weight (BW; g) relationship and FL–total length (TL) relationship were as follows: BW = 1.048 × 10⁻⁵ FL^3.121 and TL = 1.101 × FL + 2.196, respectively. The main spawning season was estimated as between April and August, since higher gonadosomatic index (GSI) values were found for both sexes, and matured oocytes were observed in females during these months. The developmental stage of ovaries correlated with the GSI of females. Fecundity ranged from 9,530 to 98,260 oocytes in fish of 177.0 to 278.0 mm FL, and the FL–fecundity relationship was as follows: fecundity = 9.525 × 10⁻⁸ FL^4.903.     

Coprophagy-related interspecific nocturnal interactions between Japanese macaques (<Emphasis Type="Italic">Macaca fuscata yakui</Emphasis>) and sika deer (<Emphasis Type="Italic">Cervus nippon yakushimae</Emphasis>)

The influence of sympatric large animals on the sleeping behavior of primates in the wild is still largely unknown. In this study, we observed behaviors of wild Japanese macaques (Macaca fuscata yakui) at their sleeping sites, using a highly sensitive video camera. We found evidence of nocturnal interspecific interactions, such as agonistic interactions, between Japanese macaques and sika deer (Cervus nippon yakushimae). Deer approached sleeping clusters of macaques, which slept on the ground, to eat their feces or unidentified materials near the sleeping clusters, and as a result, the macaques were often quickly displaced from their sleeping site. There was a significant difference in the occurrence of macaque–deer agonistic interactions between seasons. Our results suggested that the size of the sleeping cluster, the number of adult macaques in the cluster, and the existence of adult males in the cluster did not influence the occurrence of the agonistic interactions. Finally, we discuss the influence of this interaction on macaques and speculate on the influential factors leading to nocturnal coprophagy of macaques’ feces by deer.     

Distribution of the under-ice mesozooplankton in the Kara Sea in February 2002

Mesozooplankton distribution was investigated under the sea ice in the Kara Sea at five stations in February of 2002 by Juday net hauls. Copepods dominated the mesozooplankton community, accounting for 46–88% of the total abundance and 68–99% of the biomass. Oithona similis was the most abundant species in Yenisei Bay, being present with all age stages (including egg-carrying females). For the first time, Oithona atlantica (CIII–CV copepodites, females and males) were found in the southeastern Kara Sea. In the southern part, Copepoda nauplii prevailed in terms of total abundance while the mesozooplankton in the northwestern part was entirely dominated by older stages of Pseudocalanus minutus. The mesozooplankton structure appears to be determined by available food resources and increased water temperature due to a strong influence of warm Atlantic waters.     

New data on sexual dimorphism and reproductive biology of Alaska skate <Emphasis Type="Italic">Bathyraja parmifera</Emphasis> from the northwestern Pacific Ocean

New data on sexual dimorphism and features of reproductive biology of Alaska skate Bathyraja parmifera from the western Bering Sea and the northern Sea of Okhotsk are presented. Based on comparative analysis of 11 external morphological characters, the males differ from the females in the length of the disc and snout length (to the eyes, to the mouth, and to the nostrils). In the western Bering Sea, 50% of the females and 50% of the males reach the first sexual maturity at 84.5 cm TL and 85.2–90.2 cm TL, respectively; in the Sea of Okhotsk, 50% of the males reach their first sexual maturity at 80.8–83.8 cm TL (the assessment depends on the features of the method). Among smaller skates (less than 45 cm TL), the males prevail, but the proportion of the females increases in larger size groups; the sex ratio becomes equal in the exemplars 60–80 cm TL, but the males prevail again among the largest fishes (more than 80 cm TL).     

Male red deer (<Emphasis Type="Italic">Cervus elaphus</Emphasis>) dispersal during the breeding season

Breeding dispersal can be of significant ecological and evolutionary importance. Yet, it is seldom considered in mammals. I present data on male red deer (Cervus elaphus) movements between sub-populations in southern Sweden during the rut. I investigated whether these movements could be breeding dispersal driven by mate competition. During the ruts of 1998–2009, I recorded 91 movements of males. The longest movement distance was 18.5 km. Dispersal was not restricted to yearlings or sub-adults, but also observed among adult stags. Of 91 movements observed, 7 were made by yearlings, 46 by sub-adults and 38 by adults. There was a significant move among yearlings and sub-adults towards areas with a higher ratio of females/adult males and towards areas with more females. The movements between rutting areas thereby seemed driven by sexual competition.