Males rule in most of the animal world. But when it comes to conventional gender roles, lemurs -- distant primate cousins of ours -- buck the trend.
It's not uncommon for lady lemurs to bite their mates, snatch a piece of fruit from their hands, whack them in the head or shove them out of prime sleeping spots. Females mark their territories with distinctive scents just as often as the males do. Males often don't take their share of a meal until the females have had their fill.
"If a male lemur is enjoying a patch of sunlight, for example, a female is likely to push him aside and take his spot," said Joseph Petty, most recently a doctoral student at Duke University.
Most female mammals that get their way over males are well-armed to be the bullies. Dominant female spotted hyenas, for example, are bigger and heavier than males.
But female dominance in lemurs remains a puzzle. Female lemurs are no bigger than males, and they don't have antlers or bigger fangs to give them a physical edge over their mates.
Researchers at the Duke Lemur Center say females have significantly lower testosterone levels than the males across the board. But when they compared six lemur species, they found that females of some species have higher testosterone levels than others.
Petty and Duke professor of evolutionary anthropology Christine Drea examined behavior and hormone profiles in nearly 30 animals representing six closely-related species in the genus Eulemur. In four of the species, females are at the top of the pecking order, and in the other two species the sexes have equal status.
The dominant females had significantly higher male hormone levels than the females from the two more egalitarian species.
"It's strong evidence that hormones are playing a role," Petty said.
Lemurs and lorises split off from the rest of the primate family tree more than 60 million years ago, but the two species of egalitarian lemurs didn't evolve until much more recently, within the last 2 million years.
It could be that females are more sensitive to the effects of testosterone than males, stimulating aggressive behavior even though males still have more of the hormone, Petty said.
The results appear online in the journal Scientific Reports. This work was supported by grants from the National Science Foundation (IOS-0719003, IOS-1021633, BCS 1341150) and by the Margot Marsh Biodiversity Foundation.
Welcome to SUV System Ltd!
SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.
We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.
SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com
SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc
we are focus on the following fields,and hope we can help you.
Capacitor Digital Transistors Low Ohmic Resistors ST Diodes Thin Film Resistors PANASONIC Resistors SANYO IC ST Transistors TOSHIBA Transistors HARRIS IC Diodes Inc Renesas parts IC AD IC Schottky Diodes Transistors Freescale Resistor Networks Electronic News NS IC DIODES Transistors Industrial IC Rectifier Diodes Diodes Fast Recovery Diodes Atmel IC Chip Fuses NXP Transistors Freescale Semiconductor FAIRCHILD diodes Other Parts VISHAY IC MAXIM IC PANASONIC YAGEO Resistors NEC Diodes Switches Military IC Transistors Discrete Semiconductor Transistors Chip Ferrite Beads Multi-units Transistors