New research found that males can adjust the speed and effectiveness of their sperm by allocating more or less seminal fluid to copulations. The determining factor is whether the male finds the female attractive. The research revealed that many promiscuous species in the animal kingdom, including humans, can mate with many females, but chances of fertilization are greater when the female is deemed to be attractive. Full Story : Discovery.com….(Continue reading)
Even Charles Darwin struggled to explain why the bird should have this burdensome trait. When there are many potential danger related to the colourful tail, why this bird got this trait. Darwin finally got the idea of sexual selection, which provides an advantage in the competition for mates and that outweighed other disadvantages. While humans¬† are attracted to symmetrical faces and other outward signs of fitness, these birds are attracted to colourful tails. The male specific traits are evolved with the changing preferences of females. When the female tastes change, these traits go away.
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Male domination is common among primates including monkeys. But when the number of males increases, females become more strong and dominant. According to researchers, this new finding could true with humans. Male primates are usually larger than females, and it is easier for them to be stronger. But there are times where females dominate, for instance lemurs in Madagascar and macaques.
Findings support that these females are not larger than males, but they dominate due to odds. Chances of wining a fight by a female increases when male aggression is more intense and more males are defeated by other males. Therefore high-ranking females may be victorious over these losers. When females win a fight by chance, they grow more confident and win more fights, and eventually they dominate.
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According to a analysis of the ‚ÄúCollaborative Transplant Study‚Äù, female donor kidneys do not function as well in men, because to their smaller size. Women are at higher risk of rejecting a male donor kidney. Therefore, gender will be considered more in the allocation of donor kidneys in future. Data collected from almost 200,000¬† kidney recipients from 1985 to 2004 analyzed, and transplanting a female kidney was less successful than a male kidney. This is because of female kidneys have fewer nephrons. Immunological rejection problems occurred most frequently when women received a male kidney as well.
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Female chimpanzees desire to have sex with as many males as possible. They keep their mouths shut about it, to increases their chances of luring the top chimps. Scientists at the University of St Andrews explored what the copulation calls of female chimpanzees mean. They have concluded that female chimps sometimes keep quiet during sex to prevent other females from intruding, so other female rivals don’t know what they’ve been up to.
Female Chimps produce more copulation calls when high-ranking males were around to attract them. By having sex with more males causes confusion among the male chimpanzees as to which one sired the offspring. Therefore, the males are less likely to kill any babies that might be theirs.
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A man who was born female has given a birth to a girl. He underwent gender reassignment; had breasts removed; taken male hormones to get facial hair; but has kept female reproductive organs to carry a baby. His name is Thomas Beatie 34, he and his daughter are reported to be doing well in a hospital in Bend, Oregon.
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Grandmas can have babies.