New theory on why male, female lemurs same size

... of primatology's long-standing mysteries: Why are male and female lemurs the same size? In most ... on lemurs, Dunham came to the conclusion that male lemurs do guard their mates, just like other ... that fight for mating rights with females, male lemurs have evolved to passively guard their ...

Spread your sperm the smart way

... , the team mathematically modelled a range of male ejaculation strategies to look for the optimum ... to maximise their number of offspring. If a male puts a lot of resources into each mating he will ... of fewer matings. If, on the other hand, a male puts few resources into each mating he will ...

Male seahorses like big mates

... male seahorses have a clear agenda when it comes to ... Seahorses have a unique mode of reproduction: male pregnancy. male seahorses provide all post-fertilization parental ...

Nematode courting caught on camera

... mating behavior have produced video footage of a male worm preparing to mate with a hermaphrodite. ... actively co-operate in mating, it is up to the male to make and maintain the necessary contact. He ... on the other side. On finding the vulva, the male inserts his spicules and mating commences. ...

NIH expands Human Microbiome Project; funds sequencing centers and disease projects

... the skin, the nose, the vagina, the blood and the male urethra. The pilot demonstration projects ... University Purdue University at Indianapolis male urethra: Puberty, Sexual Activity and Sexually ... be collected from an ethnically diverse group of male adolescents to characterize ...

From the glass to the brain in 6 minutes

... / No differences between men and women Eight male and seven female subjects participated in the ... study found no differences between the results of male and female individuals the brains of female and male subjects reacted to alcohol consumption the same ...

Hypertension among lower-status employees lingers well into retirement

... lower prevalence of hypertension was stronger for male seniors than for female seniors. Moreover, ... more hypertension than female managers, whereas male professionals did not have more hypertension than male managers. Leigh explained that this anomaly could ...

Women faring well in hiring process for science faculty jobs at research universities

... being interviewed and receiving job offers than male applicants had. For example, women made up 20 ... were paid on average 8 percent less than their male counterparts, the report says. This difference ... in outcomes. In terms of funding for research, male faculty had significantly more funding than ...

University of Florida study provides insight into evolution of first flowers

... have four organ types: female organs (carpels), male organs (stamens), petals (typically colorful) and ... A pine tree produces pine cones that are either male or female, unlike flowers, which contain both male and female parts. But ...

Genital stimulation opens door for cryptic female choice in tsetse flies

... By snipping off parts of male genitalia and reducing genital sensation in both male and female tsetse flies, researchers induced a ... following experimental manipulation of both male and female genitalia," said William Eberhard, ...

Sexual harassment from males prevents female bonding, says study

... towards females. The researchers found that male harassment not only breaks down female social ... provides the first insight into the effect of male sexual harassment on female social networks and ... to survive in the wild. This makes the effect of male harassment quite significant, but it is an area ...

Remembrance of things past influences how female field crickets select mates

... said. "In non-social invertebrates the outcome of male ornament evolution may depend much more on the ... they exposed all females to an 'average' male song, and assessed the females' responses to it. ... songs responded more strongly to the 'average' male than those females that heard the attractive ...

Male impotence drugs may deserve a second look in women

... studies indicate the three drugs used to treat male impotence also appear to work in females, albeit ... researchers showed the drugs relax the artery in male and female rats. "It shows the drugs need to ... to constrict the internal pudendal arteries in male and female rats as they would be in a non-erect ...

Small RNAs can play critical roles in male infertility/contraception

... insight into the reproductive workings of the male sex chromosome that may have significant implications for male infertility and contraception. ... "The sex chromosome silencing in meiotic male germ cells is a well-known phenomenon, which has ...

Gene discovery could lead to male contraceptive

... children could be the key for developing a male contraceptive, according to University of Iowa ... as a gene that is involved in non-syndromic male infertility in humans, a finding which could lead ... this finding could have implications for male contraception," said Michael Hildebrand, Ph.D., ...

Men are the weaker sex

... University study provides scientific proof that a male baby comes with a bigger package of associated ... were more abundant. "Pregnancies with a male fetus are more often complicated," says Prof. ... sac and suffer from premature delivery. And those male fetuses which make it to term," he continues, ...

Female mammals follow their noses to the right mates

... under controlled conditions where the effects of male competition can be excluded ," Clutton-Brock and ... Just what can a female learn about a male through his scent? Plenty, say Clutton-Brock and ... genome tend to produce healthier offspring. So male mammals advertise their genotype via scent, and ...

Cutting-edge amfAR grants fight HIV/AIDS in the lab and on the phone

... an education and prevention intervention in which male sex workers receive information both face-to-face ... who are both popular and influential within the male sex worker community. POLs will be trained to provide appropriate information, and male sex workers will be surveyed both before and ...

Mating that causes injuries

... mating. But since it is never a good idea for a male merely to injure a female, the researchers have ... "Females' injuries as such do not benefit the male she mated with. It has been suggested rather that ... females mate with two males, it is more often the male with the longer barbs that fertilizes her eggs. ...

Early whales gave birth on land

... described fossil whales--a pregnant female and a male of the same species--reveal how primitive whales ... helpless in early life. The 8.5-foot-long male specimen, collected four years later from the ... to considerably bigger. The size difference of male and female Maiacetus is only moderate, hinting ...

Early whales gave birth on land, fossil find reveals

... described fossil whales---a pregnant female and a male of the same species--reveal how primitive whales ... helpless in early life. The 8.5-foot-long male specimen, collected four years later from the ... to considerably bigger. The size difference of male and female Maiacetus is only moderate, hinting ...

Small male chimps use politics, rather than aggression, to lead the pack, U of Minnesota study says

... most mammals, the biggest and most aggressive male claims the alpha male role and gets his choice of food and females. But ... was gleaned from 10 years of observing dominant male chimpanzees in Gombe National Park, Tanzania, ...

Stress disrupts human thinking, but the brain can bounce back

... study on stressed-out students suggests that male humans, like male rats, don't do their most agile thinking under ... the National Academy of Sciences , show that 20 male M.D. candidates in the middle of preparing for ...

Reproductive life of male mice is increased by living with females

... its species can extend the reproductive life of a male mouse by a dramatic 20 percent, according to a ... of Pennsylvania School of Veterinary Medicine, male mice were housed with or without female mice for 16 to 32 months. Each male was placed with two novel females at 2-month ...

February 2009 highlights from Biology of Reproduction

... blocks sperm. Evidence suggests that human male fertility is impacted by long-term exposure to ... and their receptors are present in the male reproductive tract, further suggesting a ... lacking FAAH, fatty acid amide hydrolase. male mice homozygous for the Faah knockout have ...

Study links water pollution with declining male fertility

... the link between water pollution and rising male fertility problems. The study, by Brunel ... This means that they inhibit the function of the male hormone, testosterone, reducing male fertility. Some of these are contained in ...

Why you can't hurry love

... Science), shows that extended courtship enables a male to signal his suitability to a female and enables the female to screen out the male if he is unsuitable as a mate. The research, ... mating game. The mathematical model considers a male and a female in a courtship encounter of ...

Why the swamp sparrow is hitting the high notes

... vocal performance (a measure of how well a male sings songs that are difficult to produce) is used as a signal in aggressive interactions between male songbirds. The study reveals that, when challenged, the male Swamp Sparrow escalates its vocal performance by ...

Male crickets with bigger heads are better fighters, study reveals, echoing ancient Chinese text

... fighters have the largest heads. In nature, male field crickets fight one another over territories ... with smaller-headed rivals. They also show that male field crickets have larger heads and mouthparts ... males increased the fighting success of the male with the larger weaponry. By examining ...

Boy or girl? It's in the father's genes

... that survived the war were more likely to have male children, which resulted in the boy-baby boom. ... the female children has her own children with a male who has the mm combination of alleles. That male determines the sex of the children, so the ...

Two from one: Pitt research maps out evolution of genders from hermaphroditic ancestors

... mutation in hermaphroditic genes that led to male and female sex chromosomes. With the ability to ... ornamentation, aversion to inbreeding, and the male inclination to sire as many offspring as ... is not complete, so hermaphrodites exist among male and female plants. Sex chromosomes in these ...

Female embryonic sexual development driven by universal factor

... in the body also is vital to female but not male embryonic sexual development, scientists report ... sex reversal: They formed ovaries, but with male characteristics, such as blood-vessel structures ... the ovaries still formed," Yao said. But male sexual structures also appeared, creating an ...

Fiddler crabs reveal honesty is not always the best policy

... of Australian ecologists has discovered that some male fiddler crabs "lie" about their fighting ability ... University measured the size of the major claw in male fiddler crabs, and two elements of fighting ... traits are likely to be generally important for male combat. Honest signalling is important for ...

Gender biases in leadership selection during competitions within and between groups

... bias when selecting leaders; preference for a male versus female leader may depend on the specific ... were presented with two candidates (one male and one female) and were told to vote for one of ... volunteers were told their group would have a male leader. The results, reported in ...

New cardiology research presented at CHEST 2008

... performing adequate chest compressions (CC) than male hospital staff. Researchers from Albert Einstein ... in New York compared the CC technique of 28 male and 30 female medical housestaff using a patient ... effort. Prior to training, 50 percent of the male group performed adequate CC, while none of the ...

Turtle doves commit adultery

... from both parental species. In order to mate, a male dove must defend his territory and attract ... to do this by determining the degree to which male doves of different species react to the coos of ... placed loudspeakers in the territory of a male dove to measure the response of the dove to other ...

Despite 'peacenik' reputation, bonobos hunt and eat other primates too

... particularly relevant for the discussion about male dominance and bonding, aggression and huntinga ... and meat consumption. By inference, the lack of male dominance and physical violence is often used to ... Overall, the discovery challenges the theory that male dominance and aggression must be causally linked ...

Researchers discover baldness gene: 1 in 7 men at risk

... an astounding sevenfold increase the risk of male pattern baldness. Their results will be published ... About a third of all men are affected by male pattern baldness by age 45. The condition's ... baldness recently surpassed $405 million. male pattern baldness is the most common form of ...

6 environmental research studies reveal critical health risks from plastic

... chemicals" that can block the production of the male sex hormone testosterone (phthalates used in PVC ... Two articles report very similar changes in male reproductive organs in rats and humans related to ... exposure to BPA and "phthalate syndrome" in rats' male offspring. "For the first time a series of ...

Researchers study acoustic communication in deep-sea fish

... to produce sound that plays a prominent role in male mating calls. These findings, published online ... in females, which was quite surprising since male fish are usually more vocal than females, said ... assumes a prominent role in sound production of male mating calls and suggest ...