Self-anointing by wild hedgehogs, Erinaceus Europaeus, in New Zealand

Of 929 wild hedgehogs examined, nineteen bore signs of recent self-anointing. The spittle deposited on the hedgehogs' backs usually gave off a sharp smell, clearly detectable some metres down-wind. Nestling animals anointed themselves when removed from their nests, possibly as a means of advertising their whereabouts to their mothers. The habit was not detected among newly-independent young animals nor among sub-adults. Among adult hedgehogs, self-anointing was confined to the breeding season, and on five occasions was elicited in the presence of other hedgehogs of the opposite sex. In this context self-anointing may serve as a form of sexual signal. When brought into captivity the self-anointing reflex is triggered by novel objects or odours and, in this unnatural context, it is argued that the behaviour falls into the category of a displacement activity, being inappropriate to the situation and seemingly purposeless.     

Vigilance in Greater Flamingos Wintering in Southern Tunisia: Age-Dependent Flock Size Effect

Decrease in individual vigilance with flock size is a widely recognized pattern in group‐living species. However such a relationship may be affected by other factors, such as age and flock composition. For instance, because young animals generally lack experience and have higher nutritional needs than adults, they can be expected not only to be less vigilant than adults but also to decrease their vigilance level by a greater extent when flock size increases than adults do. We investigated this issue using data on greater flamingos wintering in the gulf of Gabès, in southern Tunisia. Flamingos tended to congregate in small single‐age flocks for feeding, but as flock size increased, flocks became mixed. We found that when flock size increased, young flamingos significantly decreased their vigilance time, while adult did not, suggesting an age‐dependent flock size effect on vigilance. However, when flock composition (single‐age vs. mixed) was taken into account, a more complex pattern was found. Within single‐age and small flocks, no difference was found between young flamingos and adult ones regarding their vigilance level and their response to increasing flock size. However, within mixed and large flocks, adult flamingos were more vigilant than young ones, while variation in flock size did not result in a significant change in vigilance. These results suggest that young birds relied on the presence of adults, and hence more experienced individuals in detecting dangers, to reduce their vigilance and to increase their foraging time in order to satisfy their higher nutritional requirements. They could also be interpreted as a possible consequence of increasing competition with flock size which constrained more nutritionally stressed young flamingos to increase their foraging time to the detriment of vigilance.     

Factors affecting the abundance of introduced hedgehogs (Erinaceus europaeus) to the Hebridean island of South Uist in the absence of natural predators and implications for nesting birds

Introduced hedgehogs Erinaceus europaeus are a known threat to ground-nesting birds on many islands. Spring hedgehog density and sex ratio were measured over a 5-year period at four plots on the 315 km² Hebridean island of South Uist. The mean instantaneous density on the sandy-soiled machair plots (31.8 hedgehogs km⁻², se 2.95) was over twice that on the peaty-soiled blackland plots (15.4 hedgehogs km⁻², se 3.46), a difference reflecting the amount of preferred foraging habitat (mainly pasture). Plot population densities fluctuated approximately in unison. Year-to-year density changes were strongly correlated with temperature in the preceding winter and previous year's spring/summer, indicating that warmer conditions promote both survival and breeding success. The mean spring sex ratio of sub-adults (animals born in the previous calendar year) was not significantly different from 1M:1F. However, the 1.8M:1F ratio observed for adults was significantly male biased, probably a result of female mortality associated with rearing young. The study estimates that in an average year the South Uist hedgehog population numbers c . 2750 (95% confidence limit±800) adults and sub-adults and these produce around 3000 young. Compared with the native range, hedgehog densities on South Uist are shown to be unusually high, probably because their natural predators are absent. High hedgehog densities have led directly to high rates of egg predation of ground-nesting shorebirds and subsequent declines in bird populations. The results suggest that over the past 20 years egg losses have become more severe and control of hedgehogs more difficult because climate warming has resulted in generally more favourable conditions for hedgehogs on the islands.     

Self-anointing behavior in free-ranging spider monkeys (<Emphasis Type="Italic">Ateles geoffroyi</Emphasis>) in Mexico

During 250 h of observation, a total of 20 episodes of self-anointing, that is, the application of scent-bearing material onto the body, were recorded in a group of free-ranging Mexican spider monkeys (Ateles geoffroyi). The animals used the leaves of three species of plants (Brongniartia alamosana, Fabaceae; Cecropia obtusifolia, Cecropiaceae; and Apium graveolens, Umbelliferae) two of which have not been reported so far in this context in any New World primate species. The findings that only two males displayed self-anointing, that only the sternal and axillary regions of the body were rubbed with the mix of saliva and plant material, and a lack of correlation between the occurrence of self-anointing and time of day, season of the year, ambient temperature or humidity do not fit the hypothesis that this behavior functions in repelling insects and/or mitigating topical skin infections in this species. Rather, the data and the observation that the leaves of all three plant species spread an intensive and aromatic odor when crushed, support the hypothesis that self-anointing in A. geoffroyi may play a role in the context of social communication, possibly for signaling of social status or to increase sexual attractiveness.     

Serum creatine is not a reliable marker of muscular fitness in young adults

Purpose: Elevated serum creatine and higher handgrip strength are individually associated with better health profiles yet the link between two variables remains unknown. In this cross-sectional study, we evaluated serum creatine levels in relation to handgrip strength in a cohort of 130 young healthy adults (61 women and 69 men; age 23.3?±?2.6?years), while controlling for age, gender, fat-free mass and biomarkers of creatine metabolism as effect modifiers.

Materials and methods: Serum creatine, creatinine and guanidinoacetic acid (GAA) levels were measured with liquid chromatography-tandem mass spectroscopy, while handgrip strength was assessed with a hydraulic hand dynamometer.

Results: Hierarchical multiple regression revealed that our model as a whole explained 79.9% of the variance in handgrip strength (p?p?p?>?0.05).

Conclusions: Having higher blood creatine appears to be unrelated with better physical performance in young healthy adults. Serum creatine was not a reliable marker of muscular fitness in this population.     

Non-invasive methods of separating hedgehog (Erinaceus europaeus) age classes and an investigation into the age structure of road kill

The separation of animals into age classes is often fraught with difficulties, but is essential for the interpretation of survival rates and population structure. This study investigated both live hedgehogs and road kill in order to develop techniques that could be utilised to separate age classes in the field. Body measurements were taken from 24 live hedgehogs caught at a site in County Cork, Ireland over a three year period. Additionally, carcasses from around Ireland were collected and measured. There was a significant correlation between the weight and hind foot length of both live and dead hedgehogs. The weight of individuals was also significantly correlated with the body length and jaw length of hedgehogs. In all of these correlations, the sample clustered clearly into two groups with ‘juveniles’ meeting all of the following criteria: a hind foot length of <3.6 cm, a body length of <?16 cm and a jaw length of below 4.5 cm. It is suggested that these parameters, combined with the presence of growing spines, could provide a way of separating age classes in the field. This would be of particular benefit to short term studies, allowing the population structure to be accurately assessed and the reproductive success and sustainability of a population to be investigated. Road kill were also aged using the dentary bone in order to investigate the age profiles of hedgehogs killed on the road. Amongst those killed, 54 % of hedgehogs were 1-year-old or less. The majority of hedgehogs (87 %) were between 0–3-years-old, the oldest females were nine (n?=?2), and the oldest males were eight years old (n?=?2), respectively. Road kill hedgehogs had an average longevity of 1.94 years, and the mean age of females was higher (2.10 years) than males (1.87 years).     

Young and female‐biased irruptions in pygmy owls Glaucidium passerinum in southern Finland

Irruptive migrants often show biased sex and age ratio, and typically young females are the most abundant class participating in irruptions. Several hypotheses have been proposed to explain differential migration in birds. We examined these hypotheses in a sexually size‐dimorphic species (females being larger than males), the pygmy owl Glaucidium passerinum, whose migration behaviour has also been poorly documented. Migration data were collected at the Hanko Bird Observatory, SW Finland during 1979–2010. Pygmy owls showed large fluctuations in migration numbers between years. Most of the migrants were young birds and females migrated in larger numbers than males. Results support the ‘territory defence hypothesis’ since males showed weaker tendency to migrate despite the smaller body size, but the ‘dominance hypothesis’ was also supported (subordinate young outnumber dominant adults in migration numbers). Findings support the idea that in owl species, which are dependent on nesting cavities, males show lower migration behaviour than females, whereas the pattern is opposite in species which normally breed outside cavities. In addition, adults migrated later than young, likely because they need to moult remiges before departure. Early hatched young also migrated earlier than late hatched young, suggesting that more dominant young migrate first.     

The influence of environmental conditions on aspects of the time budgests of breeding ospreys

Summary Ospreys (Pandion haliaetus) were observed for 350 h in 1975 in southeastern Virginia. Other studies have demonstrated that weather can have an effect on aspects of osprey foraging behavior (e.g., frequency of diving), but for the environmental conditions observed in this study, weather and other variables did not appear to limit the ability of ospreys to feed their young.Male ospreys, which procure essentially all of the food for the family unit before the chicks fledge, spend an average of 43% of the daylight hours perched near the nest when they have unfledged young. About 1/3 of the daylight hours are utilized for hunting. Weather conditions have no effect on the time the male his perched near the nest, or on the rate of fish delivery by the male. Wind speed variability regressed positively with the time it took males to return with a fish (mean time=0.64 h/fish), but accounted for only 16% of the variation in the length of hunting trips. Size of fish delivered and rate of fish delivery were unrelated to either brood size or age of young. As the chicks age, the male spends increasing amounts of time away from the nest; this is not related to changes in weather, and appears to be due to decreasing attentiveness at the nest site by the male. Females with unfledged young spent over 95% of the daylight hours at the nest.Adults with fledged but dependent young spend an average of 1/3 of the day perched near the nest. Both adults deliver fish at this time, but together they bring no more than the male alone brought before fledging. For both adults neither the percentage of time perched near the nest nor the rate of fish delivery are related to weather conditions.     

Characterization of human tactile pattern recognition performance at different ages

This study examined tactile pattern recognition performance in human observers (N = 44) in the context of a letter recognition task at the fingertip. Participants were recruited from three different age groups (youth, n = 17; young adults, n = 14; seniors, n = 13) to examine age-related differences in performance. The influence of gender (males vs females) and hand (right vs left) was also examined. Performance was characterized in terms of both response accuracy and associated response times (RTs). Patterns of confusion between letters were also examined. Results showed that age was the most important factor in determining the capacity of our participants to perform fast and accurate pattern recognition. In this respect, younger participants (i.e., youth and young adults) clearly outperformed seniors by showing not only better accuracy and less confusion but also 2–3 times faster RT. By comparison, the combined influence of “hand” and “gender” on recognition performance was only marginal. These results indicate that the ability to perform complex tactile pattern recognition is already well established in youth 10–14 years of age with only minor refinements occurring later in early adulthood. With advancing age, such ability becomes far less efficient, as judged by the drastic increase in RT observed in seniors, in spite of a relatively good accuracy. This suggests that alterations not only at the peripheral receptor level but also at the central processing level might play an important role in limiting the ability of seniors to perform fast and efficient pattern recognition at the fingertip.     

Age-related changes in the behavior of the muscle-tendon unit of the gastrocnemius medialis during upright stance

Mechanical properties of the muscle-tendon unit change with aging, but it is not known how these modifications influence the control of lower leg muscles during upright stance. In this study, young and elderly adults stood upright on a force platform with and without vision while muscle architecture and myotendinous junction movements (expressed relative to the change in the moment on the x-axis of the force platform) were recorded by ultrasonography and muscle activity by electromyography. The results show that the maximal amplitude of the sway in the antero-posterior direction was greater in elderly adults (age effect, P < 0.05) and was accompanied by an increase in lower leg muscle activity compared with young adults. Moreover, the data highlight that fascicles shorten during forward sway and lengthen during backward sways but more so for young (-4 ± 3 and -4 ± 3 mm/Nm, respectively) than elderly adults (-0.7 ± 3 and 0.8 ± 3 mm/Nm, respectively; age × sway, P < 0.001). Concurrently, the pennation angle increased and decreased during forward and backward sways, respectively, with greater changes in young than elderly adults (age × sway, P < 0.001). In contrast, no significant differences were observed between age groups for tendon lengthening and shortening during sways. The results indicate that, compared with young, elderly adults increase the stiffness of the muscular portion of the muscle-tendon unit during upright stance that may compensate for the age-related decrease in tendon stiffness. These observations suggest a shift in the control strategy used to maintain balance.     

Mirror reactions in a zoo colony of Cebus monkeys

The extensive research investigating the reactions of a number of species of nonhuman primates to their mirror images has revealed that monkeys have never been observed to react with self-directed behaviors, as have some species of higher apes. The intermittent exposure of captive Cebus monkeys to a mirror over a 5-week period produced species-specific social reactions to the mirror, supporting the suggestion that at least in some instances the monkeys were viewing their mirror image as a conspecific. The variability in the duration and expression of mirror-directed behaviors observed in the study appeared to be related to the age and past experience of the monkeys. The duration of mirror viewing of subadults was over twice that of the adults, while the young, hand-reared animals exhibited more manipulative and fewer social behaviors than did the young animals raised in the zoo. The average viewing time of the zoo colony decreased substantially over the course of the study but the monkeys were still spending an appreciable time at the mirror after 5 weeks.     

Hand Dominance and Age Have Interactive Effects on Motor Cortical Representations

Older adults exhibit more bilateral motor cortical activity during unimanual task performance than young adults. Interestingly, a similar pattern is seen in young adults with reduced hand dominance. However, older adults report stronger hand dominance than young adults, making it unclear how handedness is manifested in the aging motor cortex. Here, we investigated age differences in the relationships between handedness, motor cortical organization, and interhemispheric communication speed. We hypothesized that relationships between these variables would differ for young and older adults, consistent with our recent proposal of an age-related shift in interhemispheric interactions. We mapped motor cortical representations of the right and left first dorsal interosseous muscles using transcranial magnetic stimulation (TMS) in young and older adults recruited to represent a broad range of the handedness spectrum. We also measured interhemispheric communication speed and bimanual coordination. We observed that more strongly handed older adults exhibited more ipsilateral motor activity in response to TMS; this effect was not present in young adults. Furthermore, we found opposing relationships between interhemispheric communication speed and bimanual performance in the two age groups. Thus, handedness manifests itself differently in the motor cortices of young and older adults and has interactive effects with age.     

Dream Content and Personality: Thick vs. Thin Boundaries

Using dream diary procedures and statistically controlling for age and gender, the present study investigated the relationship between Hartmann's (1991) boundary concept and various aspects of dreaming. Results with a sample of young adults confirmed earlier findings that persons with thin boundaries recall dreams (including nightmares) more often, report dreams that are more negative and emotionally intense, regard their dreams more favorably (i.e., as more meaningful and creative), and dream more frequently of verbal interaction with others.     

Prey selection and dietary response by wolves in a high-density multi-species ungulate community

Studies on predation by the wolf (Canis lupus) have often reported contradictory results about the role of prey density and vulnerability on wolf prey use. We investigated dietary response and prey selection by wolves in a high-density and multi-species ungulate community, analysing scats collected over a period of 11 years in the Casentinesi Forests, Italy. The second most abundant species, wild boar (Sus scrofa), was found to be the main wolf prey, and we did not observe any dietary response of wolves to variations in the density of either primary or secondary prey species. Selection patterns were uniform throughout the study period. Wolves strongly selected for wild boar piglets, while roe deer (Capreolus capreolus) fawns and adults, red deer (Cervus elaphus) adults and fallow deer (Dama dama) adults were avoided. Wolf preference for wild boar was inversely density dependent. Within each species, juveniles were preferred to adults. Medium-sized, young individuals of both wild boar and roe deer were optimal prey, although with different selection patterns related to the different anti-predator strategies adopted by each prey species. The results of this study suggest that in productive ecosystems with high density and high renewal rates of prey, selection patterns by wolves are determined by prey vulnerability, which is connected to prey age and body size. The different patterns of wild boar versus cervids use by wolf across Europe seems to be related to their relative abundances, while the strong selection of wild boar in Italian Apennines with respect to the more frequent avoidance in central-eastern Europe is better explained by higher piglet productivity and smaller body size of adults boar in Mediterranean temperate forests.     

Exploration and play in howler monkeys (Alouatta palliata)

Exploration and play were observed in eight troops of howler monkeys (Alouatta palliata) containing 56 young and 95 adults. The behavior patterns of seven age classes are described. There was a clear trend for animals to spend less time in nonsocial exploration with increasing age, and for the frequency of social play to follow an inverted “U” pattern, peaking in the early juvenile stage at 15–30 min per day. The howlers' specialization for eating large quantities of difficult to digest plant matter affected their play: as the young became increasingly dependent on plant food around the infants stage, there was a shift in their playtimes to allow for the energy demanding activity of digestion. This and other aspects of howler behavior are related to a reinforcement theory of exploration and play.     

Selenium levels in blood of Upper Silesian population

The selenium status and the relationship of whole-blood selenium and plasma homocysteine are reported for healthy human subjects living in Upper Silesia. A total of 1063 individuals (627 male and 436 female) examined for whole-blood selenium were subdivided into six groups according to age; the youngest included adolescents (n=143) aged 10–15 yr, and the oldest were centenarians (n=132). The mean Se content was relatively low (62.5±18.4 μg/L), and it tended to be higher in men (65.9±17.2 μg/L) than in women (57.5±18.9 μg/L). Selenium levels appeared to be age dependent, as the highest values were observed in young and middle-age adults (21–40 yr), whereas they were significantly lower in adolescents and in the elderly. In more than 40% of apparently healthy adults (aged 21–69 yr), the Se concentration was within the range 60–80 μg/L (i.e., below the lower limit of the nutritional adequacy range [80 μg/L]). A significant inverse correlation between whole-blood selenium and plasma total homocysteine was detected in a smaller population sample of middle-aged and elderly persons (n=204).     

Variation in response to heavy metals during vegetative growth in <Emphasis Type="Italic">Dorycnium pentaphyllum</Emphasis> Scop.

Seeds, young plants and adult plants of the perennial Mediterranean leguminous shrub Dorycnium pentaphyllum Scop. were exposed to Cd (1–100 μM) or Zn (10–10,000 μM) on nutrient solution. This species is resistant to Cd and Zn at different phenological stages. The lowest doses of Zn and Cd improved seed germination and young seedling growth, while only the highest doses of both heavy metals inhibited germination and decreased growth. High doses of Cd reduced seed imbibition and young seedling water content, while Zn did not. Osmotic adjustment was more efficient in Zn-treated young plants than in Cd-treated ones, while chlorophyll concentrations decreased in the former but not in the latter. Those differences were not observed anymore in adult plants. Exclusion processes were more efficient at the adult stage than at the young seedling stage and were more marked in response to Zn than to Cd. It is concluded that D. pentaphyllum could be used for phytostabilization of heavy metal-contaminated areas. The physiological strategies of tolerance, however, differ according to the age of the plants and the nature of the metal.     

Pet Ownership in Childhood and Socio-Emotional Characteristics,Work Values and Professional Choices in Early Adulthood

ABSTRACT

The main goal of this study, partly retrospective in character, was to explore if and how pet ownership in childhood is related to several indicators of socio-emotional development, as well as work values and professional choices in early adulthood. The sample consisted of 356 students (200 females, 156 males) from different colleges of the University of Zagreb, representing helping (n=200) and non-helping (n=156) professions. The mean age of the students was 21 years. Seventy-four percent of the participants had had a pet during childhood, mostly dogs. Participants who had owned a pet during childhood reported quite a strong attachment to it. In addition, pets were rated lower than family members and friends, but higher than television, relatives and neighbors in terms of the social support derived from them during childhood. Discriminant analysis was performed in order to examine whether young adults – those who had owned a pet during childhood and those who hadn't – differed in emotional and motivational characteristics, and whether there was a correlation with their chosen subject of study. Pet ownership in childhood was a grouping variable, while measures of current socio-emotional functioning (empathy, prosocial behavior, social anxiety and loneliness), value orientations (self-actualisation, individualistic, social, utilitarian and adventurous) and chosen subject of study (helping or non-helping profession) were predictors. A significant discriminant function was obtained. Correlations between discriminating variables and discriminant function showed that young adults who had had a pet during childhood were more empathetic, more prone to choose helping professions, and more oriented towards social values than those who did not have a pet during childhood.     

The social biology of human populations: Spontaneous group formation conforms to evolutionary predictions of adaptive aggregation patterns

Two experiments tested whether city commuter and pedestrian groups conformed with ecological predictions of adaptive group size, age, and sex composition. It was predicted that individuals with the greatest reproductive potential would optimize mating contacts and minimize competitive interference by segregating into small, mixed-sex groups, whereas more vulnerable individuals, too young or old for optimum fertility, would tend to aggregate independently of gender in larger groups, which may offer advantages for foraging and predator avoidance. To maximize reproductive potential, mature males should prefer grouping with young women of high fertility, whereas older women should prefer younger men. In Experiment 1, 2,432 persons in three cities were observed on buses, automobiles, and sidewalks, in yoked observations. As predicted, reproductively immature preschool and grade-school children formed larger groups than mature adults (p < 0.0001) and showed no sex differences in grouping. Elderly adults (with decreased reproductive potential) were also found in larger groups than younger adults (p < 0.01) and also showed no sex differences. Sexually mature men and women grouped more with the opposite sex than in all-male or all-female groups (p < 0.00001). Mature adult men were the least aggregative category (p < 0.01): they tended to be alone or in pairs with women, and all-male groups were conspicuously absent (p < 0.005). These findings were consistent across different socioeconomic levels, ethnicities, and subcultures in our samples (p = NS). In Experiment 2, 475 bus passengers in three cities were observed selecting seatmates in a naturalistic choice paradigm. Only sexually mature adults exhibited a significant preference for the sex of their seatmates (p < 0.0005): Young women chose most often to sit with other women, whereas young adult men more frequently chose seatmates of the opposite sex. Young women were chosen more often as seat partners than all age/sex categories combined (p < 0.0005). Young women chose older partners (p < 0.05), while middle-aged women preferred younger women and men (p < 0.0005) as companions. Results are explained in the context of canalized behaviors arising early in human evolution.     

Social influences on first reproductive success and related behaviors in the saddle-back tamarin (Saguinus fuscicollis,callitrichidae)

Some aspects of sociosexual behavior and the age at which maturing females experienced their first evident pregnancy and at which maturing males caused their first evident pregnancy were recorded in Saguinus fuscicolliscohabiting from 6 months of age with either an adult or a maturing sex partner. The following pair combinations and trios were studied: young male -young female, young male-adult female, adult male-young female, and adult male-young male-young female. The most frequent type of social interaction between young animals was rough and tumble play, while huddling was the most frequent interaction between young animals and their adult partners. Grooming and sexual interactions were very infrequent and there were no differences in the frequencies of these interactions among subject groups. Maturing females cohabiting with an adult male conceived significantly earlier than maturing females cohabiting with a male of their own age. Maturing males cohabiting with adult females sired offspring at a significantly earlier age than males cohabiting with a female of their own age. Some possible behavioral and physiological processes involved in the causation of early reproductive success in young tamarins cohabiting with adults are discussed. Saguinus fuscicollis fuscicollis andSaguinus fuscicollis illigeri.