Francisco Braza

Cognitive abilities, androgen levels, and body mass index in 5-year-old children

This study explores the potential relationship between a series of cognitive abilities and testosterone, dehydroepiandrosterone (DHEA), androstenedione, and body mass index (BMI) measurements in 5-year-old children. 60 boys and 69 girls were administered a test (K-BIT) which provided measurements of fluid intelligence (Matrices subtest), crystallized intelligence (Vocabulary subtest), and IQ composite (the combination of the two subtests); a sub-sample of 48 boys and 61 girls was also subjected to diverse tests related to theory of mind (affective labeling, appearance-reality distinction, display rules, and false belief). Testosterone, DHEA, and androstenedione levels were measured using an enzyme immunoassay technique in saliva samples. An analysis of variance failed to reveal any significant differences between boys and girls in any of the cognitive abilities assessed. The correlation analysis revealed a positive relationship between fluid intelligence and testosterone levels in boys, a negative relationship between crystallized intelligence and androstenedione levels in girls, and between affective labeling and androstenedione levels in boys. A multiple regression analysis indicated that androstenedione and BMI were the best predictors for some of the cognitive abilities assessed.

Social cognitive predictors of peer acceptance at age 5 and the moderating effects of gender

In this study we examined the effects of social intelligence, empathy, verbal ability and appearance-reality distinction on the level of peer acceptance, as well as the moderating role of gender. Participants were 98 five-year-old children (43 boys and 55 girls; mean age 5 years 3 months for boys and girls). Our results showed a main effect of social intelligence on peer acceptance, as well as several other effects that were moderated by gender: a significant and positive effect of verbal ability on social acceptance was found for boys; appearance-reality distinction was found to have a positive effect on social acceptance in the case of girls; and although empathy had a significant positive effect on social acceptance for both boys and girls, this effect was more pronounced among boys. Our results suggest that abilities promoting peer acceptance are different for boys and girls.

Aggression, dominance, and affiliation: Their relationships with androgen levels and intelligence in 5-year-old children

This study explores the potential relationship between social behavior (aggression, dominance, and affiliation) and testosterone, androstenedione, and DHEA measurements in 5-year-old children while also analyzing the moderating effect of IQ on the hormone-behavior relationship. 129 healthy normal Iberian children (60 boys and 69 girls) were videotaped in free play interactions in the school playground. Their behavior was then evaluated with particular emphasis on aggression, government, and affiliation. Testosterone, androstenedione, and DHEA levels were measured using an enzyme immunoassay technique in saliva samples. A test (K-BIT) which provides an IQ measurement for children was also administered to subjects. The correlation analysis revealed a positive relationship between the behavioral factor of Provocation and androstenedione in boys, and a regression analysis indicated that this relationship was moderated in a positive direction by the subjects intelligence. In girls, we observed a positive relationship between testosterone and Affectivity, with this relationship being moderated in a negative direction by intelligence.

Sleeping sites and lodge trees of the night monkey (Aotus azarae) in Bolivia

Between 1984 and 1987, we recorded the sleeping-site and lodge tree preferences of night monkeys at the Beni Biological Station, Bolivia. We characterized the structure of sleeping-site compared lodge trees to nonlodge trees, and determined the frequency of their use. Aotus azarae used branch and liana platforms on trees of the middle strate of the forest as sleeping sites, but the lodge trees provided sparse cover. Monkeys may manipulate either natural accumulations of material or bird nests to serve as sleeping sites. The characteristics of the sleeping site and of the lodge trees may be related to protection against predators and to thermal advantages. The distribution of lodge trees appeared to be related to access to food. Activities around the sleeping site could be related to marking behavior.

Genetic differentiation and phylogeography of roe deer in Spain, as suggested by mitochondrial DNA and microsatellite analysis

Abstract Current population structure patterns of roe deer Capreolus capreolus in Spain were assessed through the analysis of mitochondrial and nuclear DNA. Restriction fragment length polymorphism was detected in the D‐loop and NADH‐dehydrogenase ND1 segments of mitochondrial DNA. Nuclear variation was investigated using 12 microsatellite loci. A total of 126 roe deer were analysed from fourteen sampling sites across the Iberian peninsula, including the Andalusian population from Sierra de Cádiz, which represents the southwestern limit of the distribution of C. capreolus. Results from both mitochondrial and microsatellite variation revealed a considerable level of structuring for roe deer populations throughout the Spanish range. In particular, evidence was provided from mtDNA of a genetic differentiation of roe deer populations in northern Spain from those occurring in southern areas, with a particular distinctiveness of the Andalusian roe deer. Concordant results were obtained from classical clustering analysis based on microsatellite loci. Furthermore, a Bayesian approach to microsatellite data proved more efficiently that northern roe deer are in turn genetically heterogenous, comprising at least three subpopulations. The phylogeographic pattern suggests a history of long‐term isolation of the two main groups of roe deer populations, possibly as a consequence of the climatic changes in the Late Pleistocene. The occurrence of two genetic lineages calls for different strategies of conservation and management of this species in the Iberian Peninsula, according to the geographic distribution of populations.

Activity rhythms and use of space of a group ofAotus azarae in Bolivia during the rainy season

A group ofAotus azarae living in an island forest in the Beni region of Bolivia was observed for ten nights during the rainy season of 1985. The three members of the group, an adult male, an adult female, and the young of the year, spent 49.4% of their time resting, 31.7% feeding and 19.8% locomoting.Activity started with low intensity vocalizations about 10–15 min after sunset, the animals returning to the sleeping site in the morning, 10 to 20 min before dawn. Feeding occurred mainly during the early hours of the night, and from 1:30 a.m. to 4:00 a.m. they spent most of their time at rest.The average distance travelled per night was 337.4 m, the monkeys locomoting mainly in the first half of the night. Of the whole of the island forest (0.33 ha), our monkeys used mainly an area of 0.18 ha.

Antipredator aspects of fallow deer behaviour during calving season at Doñana National Park (Spain)

This study evaluates some morphological, ecological and behavioural aspects of fallow deer mothers and fawns during the calving season in order to know the antipredator tactics selected in this species living in a particularly open habitat at Donana National Park. In this area fallow deer give birth in synchrony during the first fortnight of June. At this time they move away from their matriarchal groups. A concentration of births in the early afternoon was detected, coinciding with the minimal activity of predators in the area. Mothers groom their offspring and ingest the birth remains to prevent the attraction of predators. During the first days of life fawns remain hidden keeping motionless.

Variation in skull morphology of roe deer (Capreolus capreolus) in western and central Europe

Variation in 21 measurements of skulls of roe deer ( Capreolus capreolus ) from eight geographic samples covering most of the range of the species in Europe was studied to assess morphological differences among populations. A total of 266 skulls of adult roe deer (133 females, 133 males) was included in the analysis; sexes were studied separately. Despite the occurrence of roe deer in a wide variety of habitats, variations in skull morphology among populations were not acute. Length of skull was the principal factor of interpopulational variability in roe deer. Variation was not distributed along clines of latitude, longitude, or elevation, but those factors did influence variation through effects on primary production, which in turn caused isolated differences in skull morphology apparently related to types of forage selected by roe deer in various geographic areas. Morphological and adaptative variation in skulls of roe deer suggested the existence of ecotypes rather than subspecies.

An analysis of mother-young behaviour of fallow deer during lactation period

In the Doñana National Park (SW Spain) female fallow deer (Dama dama ) give birth during the first fortnight of June, the next breeding season starting at the beginning of October. Between these two events the most important part of lactation takes place. Daily observations were made during the summer of 1984 and 1985. The population studied was made up of fourteen mother-young pairs that we were able to recognize individually. During each sampling period a pair of mother-young was scanned. Activities were categorized as follows: feeding, walking, selfgrooming, vigilance, mother-young interactions, and social interactions. No differences were observed in the ontogeny of behaviour neither between male and female fawns nor between their mothers. However, analysing individual differences there appeared a variation between mothers in relation to the rate of interactions towards their fawns, which was in positive correlation with the fawns weight in the case of males. Our results also suggest the possibility of higher investment in heavier female fawns. Furthermore, there is an annual variation in the maternal behaviour in relation to the availability of resources.

The Use of the Rump Patch in the Fallow Deer (D. Dama)

The rump patch of the Fallow Deer shows different visual patterns according to the activities performed by the animals. While in calm conditions the black tail sways over the white anal field; if in alarm, the tail hangs still, dividing the white field into two parts ; in higher stress the tail tends to be raised to a horizontal position, leaving the white anal field unbroken and outlined by the two lateral black stripes; if danger is impeding the tail gets erect, showing the white underside, now seen as an extension of the white anal field, or may even go up and down, the white brush of the tail appearing and disappearing On the basis of our results on the use of the rump patch and on the frequency of defecation (high in conditions of stress) and considering that the posture of the tail during defecation is one of the most frequently observed in alarm, we hypothesize that when defecation turned to function as a communicative signal of danger, a new selective force came into play, increasing the amplitude of the movements and originating the visual pattern of the rump patch that makes them more evident.