Showing posts with label gorillas. Show all posts
Showing posts with label gorillas. Show all posts

Thursday, April 14, 2011

Orangutans are lefties, chimps and gorillas right-handed

Photo showing an orangutan engaged in the TUBE task. Photo used with permission of the researcher  William Hopkins. 

Mmm, love that peanut butter
Apes are right-handed or left-handed, just like us. Not a big surprise, since they're our closest evolutionary relatives. A research team led by William Hopkins of Agnes Scott College recently tested 777 captive apes  - orangutans, gorillas, chimpanzees, and bonobos. Each ape was given a PVC tube 15 cm in length and 2.5 cm in diameter, with peanut butter smeared in both ends. The peanut butter was too far inside to reach with their mouths. The apes had to hold the tube with one hand and reach inside with a finger of the other hand. The researchers recorded which hand the apes used to reach inside for the peanut butter.  Each ape was tested on 2 to 4 occasions, in solitude if possible.

Only the orangs were left-handed
Orangutans turned out to be the only southpaws. The majority of gorillas and chimps are right-handed, as are 90% of humans. Bonobos showed no significant handedness at the population level. Hopkins believes that handedness at the population level in apes may be a result of ecological adaptations associated with posture and locomotion (personal communication with Hopkins).  He plans further research to try to understand why orangutans are left-handed, while other apes and humans are right-handed in general. It may be somehow related to the fact that orangutans are the most arboreal of the apes.

Hopkins' research will soon be published: Journal of Human Evolution 60 (2011) 605-611.

 Orangutans at a sanctuary on Borneo, drinking milk. Note that they're holding hands!  Photo: Sally Kneidel

Handedness in crows too
Apes are not the only nonhumans to display handedness.  In 2007 I wrote this post about research by Gavin Hunt of the University of Auckland, who documented handedness and tool-making in New Caledonia crows.

Post by Sally Kneidel, PhD

For further reading on primate conservation and behavior, and my observations of wild orangutans on Borneo and Sumatra, check out some of my earlier primate posts:

Some of my earlier primate posts:
Trade a major threat to primate survival. March 21, 2011
We are family: new evidence of our close link to chimps Feb 16, 2011
Is males' attraction to trucks and balls genetically based? Jan 14, 2011
Hunting may threaten orangutans even more than habitat loss Dec 6, 2010
Wildlife trade rivals drug trade in profits September 20, 2010
Laws flaunted: flourishing pet trade threatens orangutans' survival August 23, 2010
My search for a wild orangutan in Borneo and Sumatra August 16, 2010
Orangutans dwindle as Borneo, Sumatra converted to palm-oil plantations August 3, 2010
The great apes are losing ground March, 2010
The U.S. imports 20,000 primates per year. February, 2010
Baboons are Africa's most widespread primate. Females rule! December 30, 2009
Mama monkeys give in to tantrums....when others are watching. April 23, 2009
Angry chimp reveals a "uniquely human" ability. March 21, 2009
Monkeys and parrots pouring from the jungle. September, 2008
Chimps' short-term memory is better than humans'  April 2, 2008
Chimps share human trait of altruism August 3, 2007

Keywords: orangutans chimps gorillas apes handedness William Hopkins

Monday, December 06, 2010

Hunting may threaten orangutans even more than habitat loss

Wild adult male orangutan on Sumatra. Photo: Sally Kneidel

[See bottom of this page for list of my previous posts about orangutans.]
Most people are surprised to learn that unlawful traffic in wildlife and wildlife parts is the third biggest criminal activity in the world, after drugs and arms. The illegal hunting of great apes is so pervasive that it may threaten their survival even more than habitat loss does. Habitat loss is rampant these days, due to human population growth....so I wouldn't have believed that hunting could be an even bigger threat until reading a recent paper by Vincent Nijman (and 5 other scientists). Nijman is a scientist at Oxford Brookes University, a consultant to TRAFFIC, and has published numerous research papers on orangutan conservation.  He and the other authors of this particular paper collected convincing data that suggest orangutan populations have been reduced more by hunting than anything else.
 Wild male orangutan resting, Sumatra. Photo: Sally Kneidel

I crisscrossed Indonesia and Malaysia looking for orangutans

I was on the islands Borneo and Sumatra a few months ago, searching high and low for wild orangutans. That was my main reason for going to Southeast Asia.  I had researched sites carefully in advance and I chose my destinations accordingly; consequently, I was lucky enough to see a number of wild orangutans in undisturbed forests. But as Dr. Nijman writes, "Bornean orangutans currently occur at low densities and seeing a wild one is a rare event." In contrast, historic collectors like Alfred Russel Wallace in the 1800s saw many orangutans daily and "were able to shoot continuously over weeks or even months."  Clearly, orangutans are much rarer today than they were in the past. That's true not only of orangutans, but also for the other great apes.

Chimpanzees and gorillas are hunted for meat

I saw on the "Planet Green" network on November 24 a one-hour documentary about an investigation into the hunting of chimpanzees and gorillas for bushmeat in Cameroon. The investigator, Steve Galster, said these two apes are popular meat because they're so big and fleshy relative to other remaining wildlife. The primary reasons they're shot or trapped is to eat them, to sell their meat to neighbors, or to transport the meat by train or car to city markets. But when baby animals are captured after shooting the mother, the babies can be shipped abroad to be sold as pets. So killing a mother ape is doubly profitable.

Gorilla carried out of the forest. Photo courtesy of United Nations' Food and Agriculture Organization

A pet chimp brings social status

I was impressed with the diligence of the filmmakers for this Planet Green show, which featured an undercover sleuth (a local woman) equipped with a tiny concealed camera visiting a local man who was trying to sell a baby chimp. The chimp was eventually confiscated and sent to a sanctuary. Even at the sanctuary, though, young chimps are vulnerable to theft in order to sell them. The demand for them is huge.

 Baby chimp, Wikimedia Commons 

Having a baby chimp is a social asset, the narrator said - something to show off no matter where you live. I can imagine that. There aren't many things in life more interesting than a living baby ape. In this Planet Green documentary, the poachers and smugglers who were caught on film all wound up going free, through "negotiations" (bribery) or police who failed to show up in court, or officials who took pity on impoverished poachers and their children.

Strong evidence that hunting has hurt orangutans more than habitat loss

The research of Vincent Nijman (and 5 colleagues) into the hunting of orangutans on Borneo was published in the online journal PLoS ONE in August, 2010. The researchers used "encounter rates" to measure the density of orangutans over the last 150 years in a variety of different habitats on Borneo. Their data came from hunting accounts, museum collections, and field studies. By the researchers' calculations, the number of Bornean orangutans has declined about 6-fold since the mid-1800s. The convincing aspect of their data is this: If large-scale deforestation and forest degradation caused the decline, then we would expect to see a sudden decline after the 1960s and 1970s, "coincident with major intensification of [deforestation] during this period." However, encounter rates declined steadily for at least 120 years before major deforestation began. Furthermore, say Nijman et al., although orangutan numbers do generally decrease following habitat disturbance, they manage to survive in high densities in some areas that have been heavily disturbed or even clear-cut and planted with monoculture plantations. Nijman et al. also noted that local orangutan extinctions or historical declines have occurred in the same areas where we know orangutans have been heavily hunted.

 Mother and infant orangutan in forest on Borneo.  Photo: Sally Kneidel

Orangutans now extinct in upland Borneo, where hunting was heavy historically

Mother and infant orangutan on Borneo.  Photo: Sally KneidelFor example, orangutans have long been extinct in upland areas of Borneo where poor soil prevents farming - areas that were historically populated by nomadic humans forced to rely on hunting. In contrast, freshwater and peat swamp environments were mostly not inhabited by people until the 19th century, but were densely populated by orangutans. The PLoS ONE paper sites many other examples of hunting-related distribution patterns of orangutans. In eastern Sabah (a state in Borneo), roving bands of head-hunters provided a refuge for orangutans and other wildlife, because other humans were afraid to enter the area. That refuge ended when head-hunting was banned.

Nijman et al. conclude that hunting has been underestimated as a key causal factor of orantugan density and distribution, and that orangutan population declines have been more severe than previously estimated based on habitat loss only.

Why do people still hunt orangutans?

The red apes, among our closest relatives, are still hunted for food or traditional medicines, as agricultural pests, for trophies, and more recently, for the pet trade. When I was in Southeast Asia in June and July, I visited the wildlife markets of Jakarta, where vendors openly flaunt wildlife-protection laws that are seldom enforced. There I was offered pet orangutans, along with many other supposedly protected primates, protected birds, and even a baby jaguar. Many told me they were carrying on a family business that had been handed down by their fathers. For more about my time in the Jakarta markets, see this post.

Trapping, shooting, eating, and selling wildlife are long-held traditions in forest cultures. Solutions must involve enforcement of local laws protecting forests and wildlife, and enforcement of penalties. That's something that's not happening right now in developing countries. But it must if orangutans, gorillas, chimpanzees, tigers, and thousands of other species are to survive this century. Many organizations are busy, on site, trying to make it happen. In Southeast Asia, TRAFFIC and Greenpeace are working hard to turn things around.

What can you do?

Support some of the NGOs who are making the most progress in protecting orangutans from illegal hunting and trade and who are fighting to protect Southeast Asia's remaining forests from destruction.

These are some of the best:

Greenpeace International
TRAFFIC: the wildlife trade monitoring network
ProFauna (an Indonesian NGO that helped me in Jakarta by providing a local guide to go with me to the markets)
World Wildlife
ForestEthics
Rainforest Action Network
Earth Pulp and Paper

My previous posts on conservation in Southeast Asia:

Some of my previous posts on wildlife smuggling around the world:

Monkeys and parrots pouring from the jungle. September, 2008
The U.S. imports 20,000 primates per year. February, 2010
The great apes are losing ground. March, 2010

Some of my previous posts about deforestation:

Orangutans dwindle as Borneo, Sumatra converted to palm-oil plantations August 3, 2010
Wild tigers are in trouble October 4, 2010
Plush toilet paper flushes old forests. September 26, 2009

Keywords: orangutans hunting habitat loss bushmeat Planet Green gorillas chimpanzees Southeast Asia Africa TRAFFIC Greenpeace ProFauna wildlife trade wildlife smuggling