Maternal Touch Moderates Sex Differences in Juvenile Social Play Behavior

Additional somatosensory contact of preterm human infants improves a variety of developmental assessment scores, but less is known about its lasting consequences. In rodents, maternal contact may influence the programming of juvenile social play behavior. Therefore, we used a paradigm where we can control the levels of somatosensory contact associated with maternal care. We find that additional somatosensory contact of offspring can have lasting consequences on juvenile social play behavior in a sex-dependent manner. Specifically, additional somatosensory stimuli reduced male social play behavior, but did not change female play behavior. We then examined if this additional infant contact altered some neurobiological substrates associated with play within the juvenile amygdala. Control males had lower levels of 5HT2a receptor mRNA levels contrasted to females; however, similar to its sex-dependent effect on juvenile social play, males that received additional somatosensory contact had higher serotonin 5HT2a receptor mRNA levels than control males. No difference was found in females. As serotonin signaling typically opposes juvenile play behavior, these data suggest that maternal touch can program lasting differences in juvenile social play and 5HT2a receptors mRNA levels within the juvenile amygdala.     

Play Behavior in Juvenile Golden Lion Tamarins (Callitrichidae: Primates): Organization in Relation to Costs

Play is a complex behavior that is widespread among vertebrates. Despite the potential benefits for the development of social, cognitive and motor skills, play behavior has costs: energy expenditure, and the risks of injury and predation. As the fitness benefits of play are presumably to be gained as adults, we expect young animals to minimize its immediate costs. Here, we describe play behavior in golden lion tamarins (GLTs) (Leontopithecus rosalia) and test cost-minimizing hypotheses. We collected data on play behavior and adult vigilance in nine groups (four wild and five supplemented, the latter deriving from a reintroduction) of wild-living lion tamarins (16 infants) in Brazil. Results showed that play occupied 3.8% of the activity budget, occurred during the hottest times of the day, and was characterized by being mainly social, involving partners of different ages, and sometimes different species. We found no differences in playing time between wild and supplemented groups. The lion tamarins played less in ‘dangerous’ substrates (canopy branches and forest floor), and more in ‘safe’ substrates (large branches and vine tangles), and favored playing in the center of the group over the periphery. The reproductive animals were vigilant during 78% of the time the infants were playing, and were mostly oriented away from the playing animals. The observed organization of play behavior suggests that juvenile GLTs minimize the risk of predation and accidental injuries, but do not seem to minimize energy expenditure and the risks of social injuries. The social-cognitive benefits acquired from experience of older partners during play may overcome the costs of the latter behavior, and because little time was spent in play, the energetic costs may be inconsequential.     

Behavior of Juvenile Yellow-bellied Marmots: Play and Social Integration

This study is a quantitative examination of the behavior of juvenile yellow-bellied marmots (Marmota flaviventris), especially play, and an attempt to relate play to the social and population biology of marmots. An hypothesis of adaptive fine-tuning (social integration) of individual behavioral traits through play is advanced. While the data do not directly support social integration as a function of play, the results are a sine qua non of this hypothesis.     

The Ancestral Carnivore Karyotype As Substantiated by Comparative Chromosome Painting of Three Pinnipeds,the Walrus,the Steller Sea Lion and the Baikal Seal (Pinnipedia,Carnivora)

Karyotype evolution in Carnivora is thoroughly studied by classical and molecular cytogenetics and supplemented by reconstructions of Ancestral Carnivora Karyotype (ACK). However chromosome painting information from two pinniped families (Odobenidae and Otariidae) is noticeably missing. We report on the construction of the comparative chromosome map for species from each of the three pinniped families: the walrus (Odobenus rosmarus, Odobenidae–monotypic family), near threatened Steller sea lion (Eumetopias jubatus, Otariidae) and the endemic Baikal seal (Pusa sibirica, Phocidae) using combination of human, domestic dog and stone marten whole-chromosome painting probes. The earliest karyological studies of Pinnipedia showed that pinnipeds were characterized by a pronounced karyological conservatism that is confirmed here with species from Phocidae, Otariidae and Odobenidae sharing same low number of conserved human autosomal segments (32). Chromosome painting in Pinnipedia and comparison with non-pinniped carnivore karyotypes provide strong support for refined structure of ACK with 2n = 38. Constructed comparative chromosome maps show that pinniped karyotype evolution was characterized by few tandem fusions, seemingly absent inversions and slow rate of genome rearrangements (less then one rearrangement per 10 million years). Integrative comparative analyses with published chromosome painting of Phoca vitulina revealed common cytogenetic signature for Phoca/Pusa branch and supports Phocidae and Otaroidea (Otariidae/Odobenidae) as sister groups. We revealed rearrangements specific for walrus karyotype and found the chromosomal signature linking together families Otariidae and Odobenidae. The Steller sea lion karyotype is the most conserved among three studied species and differs from the ACK by single fusion. The study underlined the strikingly slow karyotype evolution of the Pinnipedia in general and the Otariidae in particular.     

Social Play among Juvenile Bighorn Sheep: Structure,Development, and Relationship to Adult Behavior

A 27-mo study of bighorn sheep (Ovis canadensis) was conducted to examine the structure and development of social play among lambs, and to compare that behavior with the behavior of yearlings and adults. Male lambs played more than females and exhibited a larger repertoire. The behavior patterns used by lambs in social play were the same as those used by adults in intrasexual conflict and courtship. However, the repertoire of lambs was more limited than that of adults. Lambs chose partners closest in age to interact with, regardless of sex. Results were consistent with the hypothesis that play serves to develop physical skills and strength.     

Social Play in the Domestic Cat

The social play of domestic cats in the laboratory and at homewas examined. Categories and sequences of motor patterns wereidentified and analyzed. The developmental period during whichsocial play was most frequent was established to be from 4 weeksto 4 months. The results suggest that social play functionsto provide specific forms of exercise and as a means of developingand maintaining social relations among littermates. The declinein social play appears to be related to dispersal of the youngand to a decrease in preference for social contact.     

The Development of Play in Preschoolers

The motives of play activity constitute a key question. It is no accident that views on play diverge most conspicuously with regard to the the stimuli leading to play. Theories of satisfaction, pleasure, internal primary drives and self-affirmation—all "in-depth theories"—are essentially theories of the motivating forces that give rise to play. The principal flaw in these conceptions is how they construe the motivating forces of play: they are situated in the subject, in the child and in the child's experiences. These theories discount the fact that these experiences are but secondary to an activity, i.e., they are symptomatic in that they indicate the activity is indeed taking place, but they tell us nothing about the real, objective, stimuli of the activity.     

Serum Chemistry Reference Ranges for Steller Sea Lion (Eumetopias jubatus) Pups from Alaska: Stock Differentiation and Comparisons Within a North Pacific Sentinel Species

Blood chemistry and hematologic reference ranges are useful for population health assessment and establishing a baseline for future comparisons in the event of ecosystem changes due to natural or anthropogenic factors. The objectives of this study were to determine if there was any population spatial structure for blood variables of Steller sea lion (Eumetopias jubatus), an established sentinel species, and to report reference ranges for appropriate populations using standardized analyses. In addition to comparing reference ranges between populations with contrasting abundance trends, data were examined for evidence of disease or nutritional stress. From 1998 to 2011, blood samples were collected from 1,231 pups captured on 37 rookeries across their Alaskan range. Reference ranges are reported separately for the western and eastern distinct population segments (DPS) of Steller sea lion after cluster analysis and discriminant function analysis (DFA) supported underlying stock structure. Variables with greater loading scores for the DFA (creatinine, total protein, calcium, albumin, cholesterol, and alkaline phosphatase) also were greater for sea lions from the endangered western DPS, supporting previous studies that indicated pup condition in the west was not compromised during the first month postpartum. Differences between population segments were likely a result of ecological, physiological, or age related differences.     

Inter-Population Movements of Steller Sea Lions in Alaska with Implications for Population Separation

Genetic studies and differing population trends support the separation of Steller sea lions (Eumetopias jubatus) into a western distinct population segment (WDPS) and an eastern DPS (EDPS) with the dividing line between populations at 144° W. Despite little exchange for thousands of years, the gap between the breeding ranges narrowed during the past 15–30 years with the formation of new rookeries near the DPS boundary. We analyzed >22,000 sightings of 4,172 sea lions branded as pups in each DPS from 2000–2010 to estimate probabilities of a sea lion born in one DPS being seen within the range of the other DPS (either ‘West’ or ‘East’). Males from both populations regularly traveled across the DPS boundary; probabilities were highest at ages 2–5 and for males born in Prince William Sound and southern Southeast Alaska. The probability of WDPS females being in the East at age 5 was 0.067 but 0 for EDPS females which rarely traveled to the West. Prince William Sound-born females had high probabilities of being in the East during breeding and non-breeding seasons. We present strong evidence that WDPS females have permanently emigrated to the East, reproducing at two ‘mixing zone’ rookeries. We documented breeding bulls that traveled >6,500 km round trip from their natal rookery in southern Alaska to the northern Bering Sea and central Aleutian Islands and back within one year. WDPS animals began moving East in the 1990s, following steep population declines in the central Gulf of Alaska. Results of our study, and others documenting high survival and rapid population growth in northern Southeast Alaska suggest that conditions in this mixing zone region have been optimal for sea lions. It is unclear whether eastward movement across the DPS boundary is due to less-optimal conditions in the West or a reflection of favorable conditions in the East.     

The Development of Play in the South American Fur Seal

Play behaviour in the juvenile South American fur seal (Arctocephalus australis) is described for the period of dependence on the mother (up to 32 months). Play does not appear to be a unitary category of behaviour, but may be separated into four distinct types: terrestrial social and solitary play and swimming social and solitary play. These four types show different development profiles, and appear to serve different functions. Terrestrial solitary play and the two swimming play forms appear to be juvenile specializations, the first to enable very young seals to gain motor skills rapidly in order to avoid dangers from conspecifics, the second two to enhance antipredator behaviour and foraging ability during the gradual transition to independence. In contrast, social play may be best thought of as gaining social skills necessary in adult life, prior to dispersal post-weaning. Juvenile fur seals which do not wean in their first year show an upsurge in social play which is not seen in the other play types. This upsurge coincides temporally with the peak of social play of the new cohort, and is presumably elicited by them.     

Sex Differences in the Play Behavior of Yearling Yellow-bellied Marmots

Play in yearling yellow-bellied marmots (Marmota flaviventris) was studied under non-manipulative field conditions in the Upper East River Valley of Colorado. The behavior patterns constituting play were described and illustrated and 12 specific hypotheses related to sex differences were tested. The results of these tests were used to evaluate the adaptive significance of play by comparing two major functional hypotheses: motor training and social cohesion.     

Development of Social Behavior in the Fallow Deer (Dama dama)

An einer halbwilden Herde des Damhirsches (Dama dama) wurde 19 Monate lang das Sozialverhalten, vor allem die Bedeutung frühontogenetischer Erfahrungen für die Entwicklung des arttypischen Verhaltens untersucht. Zahlreiche optische, akustische und Berührungs-Reize dienen der Warnung, der Rangordnung oder der Verständigung zwischen Geschlechtspartnern oder Eltern und Kindern. Isoliert aufgezogene Jungtiere reagierten in typischen Situationen mit den gleichen Signalen wie in der Herde aufgewachsene und beantworteten, in die Herde gebracht, die arttypischen Signale der anderen richtig. Allerdings wurden diese Tiere von der Herde nicht aufgenommen und standen noch nach 3 Jahren abseits. Die isolierte Aufzucht beeinträchtigt also das Sozialleben stark, indem es die Bindung an Artgenossen verhindert. Diese Bindung ist aber wohl nötig, wo bestimmte Verhaltenselemente von Artgenossen gelernt werden müssen.     

The Evolution of Reptilian Social Behavior

Reptiles display a diversity of behavior that is reflectiveof their evolutionary heritage from fish and amphibians andtheir ancestral contribution to the diversity found in birdsand mammals. Much of the behavior observed in reptiles seemsspecific to the ecological setting within which they live. Asa result, a diversity of behavior is found in each of the groupsof modern reptiles. Recent studies on the social behavior oflizards have proved them capable of a variety of behavioralpostures, sequences, and sociality that exceeds that found insome mammals and birds. While many species of lizards are territorial,others are hierarchial and some have harems. For all those territorialspecies studied, crowding results in increased social interaction,increased aggression, and a switch to hierarchial behavior. While smell and sound may be important stimuli for social behaviorin some reptiles, posture, actions, and especially color appearto be most important in diurnal lizards. Temperature and energystudies suggest that the large extinct dinosaurs probably foughtconsiderably less than commonly portrayed in movies and stories,but were also probably much more brightly colored than commonlyshown in reconstructions.     

No Evidence of Metabolic Depression in Western Alaskan Juvenile Steller Sea Lions (Eumetopias jubatus)

Steller sea lion (Eumetopias jubatus) populations have undergone precipitous declines through their western Alaskan range over the last four decades with the leading hypothesis to explain this decline centering around changing prey quality, quantity, or availability for this species (i.e., nutritional stress hypothesis). Under chronic conditions of reduced food intake sea lions would conserve energy by limiting energy expenditures through lowering of metabolic rate known as metabolic depression. To examine the potential for nutritional stress, resting metabolic rate (RMR) and body composition were measured in free-ranging juvenile Steller sea lions (N = 91) at three distinct geographical locations (Southeast Alaska, Prince William Sound, Central Aleutian Islands) using open-flow respirometry and deuterium isotope dilution, respectively. Average sea lion RMR ranged from 6.7 to 36.2 MJ d⁻¹ and was influenced by body mass, total body lipid, and to a lesser extent, ambient air temperature and age. Sea lion pups captured in the Aleutian Islands (region of decline) had significantly greater body mass and total body lipid stores when compared to pups from Prince William Sound (region of decline) and Southeast Alaska (stable region). Along with evidence of robust body condition in Aleutian Island pups, no definitive differences were detected in RMR between sea lions sampled between eastern and western populations that could not be accounted for by higher percent total body lipid content, suggesting that that at the time of this study, Steller sea lions were not experiencing metabolic depression in the locations studied.     

The Effects of Birth Weight and Maternal Care on Survival of Juvenile Steller Sea Lions (Eumetopias jubatus)

Steller sea lions were listed as endangered following a collapse of the western distinct population beginning in the late 1970s. Low juvenile survival has been implicated as a factor in the decline. I conducted a multistate mark-recapture analysis to estimate juvenile survival in an area of the western population where sea lions are showing signs of recovery. Survival for males and females was 80% between 3 weeks and 1 year of age. Approximately 20% of juveniles continued to be nursed by their mothers between ages 1 and 2 and 10% between ages 2 and 3. Survival for juveniles that suckled beyond 1 year was 88.2% and 89.9% to ages 2 and 3, respectively. In contrast, survival for individuals weaned by age 1 was 40.6% for males and 64.2% for females between ages 1 and 2. Birth mass positively influenced survival for juveniles weaned at age 1 but had little effect on individuals continuing to suckle. Cumulative survival to age 4 was double that estimated during the population decline in this region. Evidence suggests that western Steller sea lions utilize a somewhat different maternal strategy than those in the eastern distinct population. Western adult females generally invest more in their pups during the first year but wean offspring by age 1 more often. This results in better survival to age 1, but greater mortality between ages 1 and 3 compared to the eastern population. Different maternal strategies may reflect density dependent pressures of populations at opposite levels of abundance.     

The Effect of Novel Research Activities on Long-term Survival of Temporarily Captive Steller Sea Lions (Eumetopias jubatus)

Two novel research approaches were developed to facilitate controlled access to, and long-term monitoring of, juvenile Steller sea lions for periods longer than typically afforded by traditional fieldwork. The Transient Juvenile Steller sea lion Project at the Alaska SeaLife Center facilitated nutritional, physiological, and behavioral studies on the platform of temporary captivity. Temporarily captive sea lions (TJs, n = 35) were studied, and were intraperitoneally implanted with Life History Transmitters (LHX tags) to determine causes of mortality post-release. Our goal was to evaluate the potential for long-term impacts of temporary captivity and telemetry implants on the survival of study individuals. A simple open-population Cormack-Jolly-Seber mark-recapture model was built in program MARK, incorporating resightings of uniquely branded study individuals gathered by several contributing institutions. A priori models were developed to weigh the evidence of effects of experimental treatment on survival with covariates of sex, age, capture age, cohort, and age class. We compared survival of experimental treatment to a control group of n = 27 free-ranging animals (FRs) that were sampled during capture events and immediately released. Sex has previously been show to differentially affect juvenile survival in Steller sea lions. Therefore, sex was included in all models to account for unbalanced sex ratios within the experimental group. Considerable support was identified for the effects of sex, accounting for over 71% of total weight for all a priori models with delta AICc <5, and over 91% of model weight after removal of pretending variables. Overall, most support was found for the most parsimonious model based on sex and excluding experimental treatment. Models including experimental treatment were not supported after post-hoc considerations of model selection criteria. However, given the limited sample size, alternate models including effects of experimental treatments remain possible and effects may yet become apparent in larger sample sizes.     

The Development of Reflection Through Learning

The article introduces a famous labyrinth task used to demonstrate children's different approaches to learning tasks. The author connects reflection to children's questions concerning personal learning tasks beyond teacher assignments. She assigns a special role in this to child's personal search in charting the limits of the unknown. Child's active exploration should focus on new methods. Development of reflection in the frame of developmental teaching sets new paradoxical requirements to teachers.     

Age Specific Survival Rates of Steller Sea Lions at Rookeries with Divergent Population Trends in the Russian Far East

After a dramatic population decline, Steller sea lions have begun to recover throughout most of their range. However, Steller sea lions in the Western Aleutians and Commander Islands are continuing to decline. Comparing survival rates between regions with different population trends may provide insights into the factors driving the dynamics, but published data on vital rates have been extremely scarce, especially in regions where the populations are still declining. Fortunately, an unprecedented dataset of marked Steller sea lions at rookeries in the Russian Far East is available, allowing us to determine age and sex specific survival in sea lions up to 22 years old. We focused on survival rates in three areas in the Russian range with differing population trends: the Commander Islands (Medny Island rookery), Eastern Kamchatka (Kozlov Cape rookery) and the Kuril Islands (four rookeries). Survival rates differed between these three regions, though not necessarily as predicted by population trends. Pup survival was higher where the populations were declining (Medny Island) or not recovering (Kozlov Cape) than in all Kuril Island rookeries. The lowest adult (> 3 years old) female survival was found on Medny Island and this may be responsible for the continued population decline there. However, the highest adult survival was found at Kozlov Cape, not in the Kuril Islands where the population is increasing, so we suggest that differences in birth rates might be an important driver of these divergent population trends. High pup survival on the Commander Islands and Kamchatka Coast may be a consequence of less frequent (e.g. biennial) reproduction there, which may permit females that skip birth years to invest more in their offspring, leading to higher pup survival, but this hypothesis awaits measurement of birth rates in these areas.