Mostrando entradas con la etiqueta Lemures. Mostrar todas las entradas
Mostrando entradas con la etiqueta Lemures. Mostrar todas las entradas

jueves, 14 de agosto de 2008

New Rare Lemur Group Found in Swamp

lemur photo


July 22, 2008—A new population of wrinkly-faced, bamboo-eating lemurs has been found in a swampy region of east-central Madagascar—more than 240 miles (400 kilometers) from the other only known group of the primates, listed as critically endangered by the World Conservation Union, conservationists announced today.

The 2007 finding comes after years of rumors that the so-called greater bamboo lemur had been sighted in the Torotorofotsy wetlands. Now that it's confirmed, the newfound group has renewed experts' hopes that the species will survive.

"Finding the extremely rare Prolemur simus in a place where nobody expected it was probably more exciting than discovering a new lemur species," conservation geneticist Edward Louis of Henry Doorly Zoo said in a statement.

Louis coordinated the joint research mission between the zoo and MITSINJO, a Malagasy nonprofit. The work was supported by the Margot Marsh Biodiversity Foundation and Conservation International.

(Read about three new species of palm-size lemurs found in Madagascar in 2006.)

Scientists suspect that 30 to 40 of the lemurs—known for cracking open giant bamboo with their powerful jaws—live in the wetland, where bamboo is still their main staple.

The new group joins another population of about a hundred animals in the island's northern bamboo forests, which are under threat from illegal logging and habitat destruction, according to Conservation International.

—Christine Dell'Amore

Photograph courtesy Jonathan Linus Fiely/Conservation International

"Cross Dressing" Lemurs Appear Male to Avoid Conflict




Matt Kaplan
for National Geographic News
July 24, 2008
 
Young female red-fronted lemurs in Madagascar adopt male coloration to dupe their aggressive female groupmates, a new study found.

These "cross dressing" primates thus avoid the wrath of older females, which would attack them to reduce sexual competition.

All red-fronted lemurs are born with the same greyish brown fur and rusty-red crowns that distinguish adult males. 

At 7 to 17 weeks later, females' coats change to a cinnamon hue, and their crowns become white.

"We knew from our longer-term observations that there was a lot of female aggression in red-fronted lemurs," said study author Claudia Fichtel of the University of Göttingen's German Primate Center.

"Females compete fiercely over limited breeding opportunities, and we wanted to know if hiding femininity was a way to avoid being attacked," Fitchtel said.

(See a photo of an endangered ring-tailed lemur.)

Not a Target

German researchers monitored a wild lemur population in the Kirindy forest in western Madagascar for five months and recorded behavioral changes as their coats changed color. 

But the scientists also faced a problem: Since all infants appear male, the theory that young sport different colorations to thwart conflicts is tricky to investigate. 

This led Fichtel and her colleagues to look very closely at older females and monitor their attacks. 

They found that males and all young females disguised as males were not targeted by the hostile older females.

Fichtel and her colleagues argue that appearing male has evolved as a defense to keep females from attacking until the masquerading females are strong enough to handle it. That tends to be between 7 and 17 weeks of age.

(Related: "Rainfall Helps Baby Lemurs Survive, Tooth Study Shows" [November 14, 2005].)

Red-fronted lemurs are not the only primates whose youngsters are colored differently than adults. 

In other species this disparity has often been explained as an adaptation that makes infants more noticeable to groupmates. Adults are then more likely to care for and protect infants, Fichtel added.

The study appears in the July issue of the Journal of Physical Anthropology.

Female Dominance

"This provides a fresh perspective into why some primate offspring have a dramatically different coat color," said Sylvia Atsalis, a primatologist at Lincoln Park Zoo in Chicago.

"It tickles scientific minds to think—through a new perspective—about a condition that occurs in many species," she added.

More in-depth analyses should be made into female lemurs and their behaviors, other scientists said.

"There has been a long-running argument about how aggressive red-fronted lemurs are to each other," said Alison Jolly, a primatologist at the University of Winchester in the United Kingdom.

"Most of their social life is cuddling and grooming, [but] once in a long while females viciously throw other females out of the group, or more rarely, they have been seen to kill and actually eat another animals' infants," she said. 

"The question is, Is infanticide or targeting so rare that it couldn't have much influence over evolutionary time?"

(Read: "Ecotourism Driving Tibetan Monkeys to Infanticide" [July 20, 2007].)

Patricia Wright, a primatologist at Stony Brook University in New York, added that genetic tests should be done to see how lemurs perceive color.

"We've only recently learned that not all lemurs see color," Wright said.

"Sometimes only females have color vision, a trait that makes males dependent upon them for finding berries and secures female dominance."