To reveal the reproductive biology in male bottlenose dolphins (Tursiops truncatus), circulating gonadotropins (follicle stimulating hormone [FSH] and luteinizing hormone [LH]) and testicular hormones (testosterone and inhibin) were monitored for 8-12 years in 2 captive bottlenose dolphins (Mars and Regulus). During the study period, Mars was undergoing sexual maturation, whereas Regulus was al...

The timing of sexual maturation in non-avian dinosaurs is not known. In extant squamates and crocodilians it occurs in conjunction with the initial slowing of growth rates as adult size is approached. In birds (living dinosaurs) on the other hand, reproductive activity begins well after somatic maturity. Here we used growth line counts and spacing in all of the known brooding non-avian dinosaur...

Juvenile growth rate is an important life-history trait that affects the size at maturity, and may influence the development of sexual ornamentation. The sword of several species of the genus Xiphophorus (Teleostei: Poeciliidae) is an elaborate secondary sexual trait that confers an advantage in terms of sexual selection, counterbalanced by locomotive and predatory costs. This study assesses di...

Growth and body height have always been topics interesting to the public. In particular, the stupendous increase of some 15-19cm in final adult height during the last 150 years in most European countries (the "secular trend"), the concomitant changes in body and head proportions, the tendency towards early onset of sexual maturation, the changes in the age when final height is being reached, an...

The age of menarche among Indian girls, which is reported to be declining, ranges from 11.5–14.5 years, with the current average age being 13.5 years. This has resulted in earlier onset of puberty and secondary sex characteristics, and increased reproductive exposure. (Bhatia,1993) With sexual maturation taking place earlier and the age of marriage delayed, the period of non-marital fecundity, ...

We reared ICR mice during a growth period (3 to 10 weeks of age) and examined the effect of exercise induction, by enriching the rearing environment with obstacles such as ladders, compared to the standard environment. Environmental enrichment significantly increased the amount of exercise in both sexes (P<0.01). Enriched exercise mice had higher body weight than control mice at 6 to 9 weeks of...

Upon sexual maturation, olfactory acuity in women ameliorates and starts oscillating across the cycle. During ovulation, mean olfactory threshold is 30 times lower than during bleeding. Interestingly, menstruated women undergo maleodorant trimethylaminuria. We argued that olfactory amelioration during ovulation might concur to a mating strategy, whereas olfactory impairment during bleeding migh...

To establish the optimal age of sexual maturation in Egyptian children, Tanner's maturity stages were determined for a sample of children and adolescents (1550 girls, 1563 boys) ranging from 6.5 to 18.5 years. The mean age for attainment of pubic hair (stage PH2) was 10.46 (SD 1.36) years for girls and 11.86 (SD 1.45) years for boys. For axillary hair (stage A2), mean age was 11.65 (SD 1.62) ye...

BACKGROUND Sex differences in levels of C-reactive protein (CRP) are well established in adulthood, but little is known about when and why they emerge. Here, we tested longitudinal models of CRP levels from ages 9 to 21, when marked physical and behavioral changes could contribute to growing sex disparities in CRP. METHODS Data from the community-based prospective-longitudinal Great Smoky Mou...

Some animals migrate long distances to exploit important seasonal food resources in the northern regions of the northern hemisphere, whilst avoiding winter starvation. Changes in the individual's age and navigational skills are likely to affect migration, which in turn influences the geographic distribution of individuals. Processes such as sexual maturation and navigational abilities are affec...