Primatology.net

A paper released this earlier this week has been first to document spontaneous prosocial behaviour in chimpanzees, finally drawing a line under the question as to whether the welfare of others is considered during choice making in this species; a controversial topic, where such behaviours have been often concluded to be absent in any primate apart from humans (generally from research within the social sciences). This research was carried out at the Yerkes National Primate Research Center by Victoria Horner, and Frans de Waal.

Pairs of chimpanzees (Pan troglodytes) where placed into testing rooms, separated by a mesh barrier. One individual had access to 30 tokens, divided into two separate colours – all of which could be given to the experimenter in exchange for food. Half of these when exchanged resulted in a selfish outcome in which only the individual handing the token received a reward, whereas the other half resulted in an altruistic outcome where both individuals received an equal reward. The individual handing the tokens to the experimenter was rewarded regardless.

If chimpanzees where choosing under a system driven by selfish interests, there should be a preference towards the choice where only the individual in control of the tokens receives a reward, and if the choice was purely random, each token would be expected to be seen 50% of the time. However, it was found that pairs where significantly more likely to share a reward (displaying prosocial behaviour), than choose the selfish option.

Victoria Hornera, J. Devyn Cartera, Malini Suchaka, and Frans B. M. de Waal (2011). Spontaneous prosocial choice by chimpanzees Proceedings of the National Academy of Sciences : 10.1073/pnas.1111088108

Alright fine. Maybe these black and gold howler monkeys are not Whitney Houston and they don’t think veganism is whack but new observation had shown that these howler monkeys actually raid chicken coop (or bird nests) for eggs. Yes, for food not to paint Easter eggs.

Thought to be exclusively folivores, the black and gold howler monkeys (Alouatta caraya) feed mainly on leaves, fruits and other parts of the plants such as flowers and bark. However, the population of black and gold howler monkeys in the forest of Rio Grande do Sul, Brazil had been observed eating eggs. “Alouatta is the most studied New World primate genus in the wild and there is not a single observation of intentional ingestion of animal matter in the literature”, said primatologist Dr. Julio Bicca-Marques.

In 2005 Ms Helissandra Prates, a student of Dr Bicca-Marques, observed two juvenile black and gold howler monkeys (Alouatta caraya) licking the interior of a dove’s nest at Estancia Casa Branca, a 2 ha orchard forest in Alegrete. The nest contained a broken egg shell. She later found evidence of egg remains in howler monkey dung collected from the orchard floor.

Then in 2007, Ms Muhle, another of Dr Bicca-Marques’s students, witnessed howler monkeys eating birds’ eggs at a separate woodland site at Beco Xavier. Over an eight month period, she recorded 19 separate instances of egg predation by a group of five individuals. All these later cases involved chicken eggs, which the monkeys stole from a chicken coop. While all five monkeys were seen to enter and investigate the coop, most of the eggs were actually eaten by a single subadult male.

-  Walker M. 2009. Monkeys ‘reject vegetarianism’. BBC.

The evolution of egg-eating is localized in this population, leading researchers to think that it is a response to environmental conditions. There is a high density of howler monkeys living in a habitat with low food sources.Bicca-Marques et al. think that eggs act as a surrogate supplementary source of protein because of the low food diversity. The shift from folivory to omnivory reflects the flexibility of the black and gold howler monkey’s diet. Watch the video of a black and gold howler monkey raiding a chicken coop.

Dr Julio Bicca-Marques and her colleagues from the Primatology Research Group published their findings in the International Journal of Primatology. The paper, “Habitat Impoverishment and Egg Predation by Alouatta caraya” is available in .pdf form through SpringerLink for free.

A quick Google search reveals that local zoos feed their black and gold howler monkeys meat and eggs such as Connecticut’s Beardsley Zoo. Interesting. Coincidence?

This finding reminds me of the dietary shift and exploitation of new food sources in chimpanzees. We know that Gombe chimpanzees (Pan troglodytes schweinfurthii) prey on red colobus monkeys (Colobus badius tephrosceles) (Stanford et al., 2005) while savanna chimpanzees (Pan troglodytes verus) from Fongoli hunt lesser bushbabies (Galago senegalensis) using spear-like tool (Pruetz and Bertolani, 2007). Will we see more published paper about dietary shift and exploitation of new food sources? I guess it would have to be a trend as these primates lose more and more of their food sources and habitat. Perhaps those with a flexible diet will better adapt to their changing environment and ecology.

Sorry PETA. It seems that omnivory is in and veganism is out.

References:

Animation of chimpanzee yawning from Emory University. Illustration from BBC News.

I’m sure we are all familiar with this scenario: Someone yawns and we would “catch” it or vice versa. This is the phenomenon of contagious yawning. A new paper from The Proceedings of The Royal Society “Computer animations stimulate contagious yawning in chimpanzees” suggests that the phenomenon of contagious yawning and empathic response to animation occurs in chimpanzees. Computer animations of yawning chimpanzees (see illustration above) can be use to stimulate contagious yawning in chimpanzees. Previous researches have documented contagious yawning in chimpanzees through video-recorded footage.

Dr. Matthew Campbell, lead author of the paper from Emory University’s Yerkes National Primate Research Center said that they would also like to learn more about behaviors that are related to empathy such as consolation (when an individual does something nice to the victim of aggression). They want to know if individuals that are good contagious yawners are also good consolers. Understanding how chimpanzees empathize and imitate animations can help us understand how we, as human beings, empathize and imitate animations as well, said Dr. Campbell.

Originally posted on The Prancing Papio.

A Fongoli chimp. Photo by Frans Lanting, National Geographic.

I just stumbled upon this on Twitter (Thanks to DarwinMonkey). It’s a National Geographic page about the Senegalese Fongoli chimps, named after the Fongoli stream that runs through the chimpanzee’s range. There are videos showing these chimps using tools fishing for termites, hunting a bushbaby and taking baths. Mary Roach’s field note-like article “Almost Human” offers readers an insight to what the daily life of a chimpanzee is like (the Fongoli chimps are savanna-woodlands chimp), the concept of “ecological intelligence” and innovative tool use by the Fongoli chimps that were suppose to be unique to humans. Read about “Almost Human” on National Geographic.

Originally posted on The Prancing Papio.

A research from Duke University by Daniel Schmitt, associate professor of evolutionary anthropology, and Tracy Kivell, a post-doctoral research associate, shows that human evolved from tree climbing ancestors, not from knuckle-walkers. Schmitt and Kivell examined and compared the wrist bones of humans and African apes. Their research, “Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor“, was published in the Proceedings of the National Academy of Sciences on August 10th, 2009.

They also found that knuckle walking evolved at least two different times; gorillas fundamentally knuckle walk differently than chimpanzees and bonobos.

Kivell and Schmitt think this suggests independent evolution of knuckle-walking behavior in the two African ape lineages.

Some scientists point to features in the human anatomy as our own vestiges of a knuckle-walking ancestry. One notable example is the fusion a two wrist bones that could provide us extra stability, a feature we share with gorillas, chimps and bonobos.

But some lemurs have that feature too, and they do a variety of different movements in the trees but do not knuckle-walk, Kivell said.

Altogether, the evidence leans against the idea that our own bipedalism evolved from a knuckle-walking ancestor, the pair wrote. “Instead, our data support the opposite notion, that features of the hand and wrist found in the human fossil record that have traditionally been treated as indicators of knuckle-walking behavior in general are in fact evidence of arboreality.”

In other words, a long-ago ancestor species that spent its time in the trees moved to the ground and began walking upright.

There are no fossils from the time of this transition, which likely occurred about seven million years ago, Kivell and Schmitt said. But none of the later fossils considered to be on the direct human line were knuckle-walkers.

Read more on Science Daily: Bipedal Humans Came Down From The Trees, Not Up From The Ground

Originally posted on The Prancing Papio

A baby orangutan being tickled. Photo from Discovery News.

We’re not the only species that are capable of laughing according to new study. Great apes are able to laugh like humans too, and they do it frequenty. This finding suggests that the last common ancestor of humans and apes also laughed around 10 to 16 million years ago. The ability to laugh subsequently evolved among apes and human, resulting in distinctive ways of laughing among them.

“Orangutans produce a short laugh series of noisy calls. Gorillas, chimps and bonobos produce longer laugh series and the calls are produced more rapidly” said project leader Marina Davila Ross, a primatologist from University of Portsmouth. With partners Michael Owren and Elke Zimmermann, Davila Ross recorded over 800 recordings of 22 juvenile and infant apes, and also three human babies laughing as they were tickled in their palms, feet, necks and armpits.

Presented in the latest edition of Current Biology, the study shows that human laughter is most similar to that of chimpanzees and bonobos, followed by gorillas and orangutans. Human laughter is least similar to those of siamangs, a lesser ape. “These results coincide with the genetic topology of great apes and humans,” said Davila Ross. She doesn’t rule out if apes or monkeys have a sense of humor but said that “it is difficult to find a method to accurately test it”.

Read the rest of the article from Discovery News: Chimps, Other Apes Laugh Like People.

I wonder what function does laughing serve in primates.

Originally posted on The Prancing Papio.

From John Hawks comes distressing news of a 90% decline in headcount of chimpanzees from Côte d’Ivoire, published in the latest issue of Current Biology. The paper, “Alarming decline of West African chimpanzees in Côte d’Ivoire,” is authored by some familiar names. One that I quickly recognized is Christophe Boesche, who captured videos of chimpanzee nut cracking behavior.

West African Chimpanzees

The team conducted a survey of the chimpanzees and found only 800 to 1,200 individuals, which is a significant drop from the down 8,000 to 12,000 individuals counted in 1989-90. The drop in chimpanzees correlates Côte d’Ivoire’s 50% growth human population sizes. With the increased human footprint comes more hunting and deforestation, driving chimpanzee populations down.

In 8 of the 11 survey sites, researchers found significantly fewer chimp nests than had been found in 1989-90. In Marahoué National Park, study co-author Campbell found only one nest, versus 234 in 1989-90.  The only site that did not experience a decline in population is the Taï National Park, a UNESCO World Heritage site that has benefited from intensive research and conservation efforts. The Taï numbers suggest that the apes’ numbers respond to stable conservation efforts.

Our collective knowledge of west African chimps is far less than the east African chimp populations. With recent findings, like the 4,300 years of continuous nut cracking behavior among these populations, we’ve only begun to understand the depth of their behaviors and abilities.

Campbell G, Kuehl H, Kouamé PN, Boesch C. 2008. Alarming decline of West African chimpanzees in Côte d’Ivoire. Current Biology 18, R903-R904. DOI:10.1016/j.cub.2008.08.015

A couple of the most popular posts of all time, here at Primatology.net, have been the cute-overload-esque ones, such as the baby macaque and white pigeon friendship and the orangutan and Sumatran tiger bond. Similar to the latter story, a new one has emerged of a chimpanzee named Anjana ‘adopting’ two white tiger cubs named Mitra and Shiva, over at The Institute of Greatly Endangered and Rare Species (TIGERS) in South Carolina.

The story behind the adoption revolves around Anjana’s caregiver, China York, and the bond they share. China raised Anjana and Anjana has mimicked her human caregiver in caring for other animals at the institute, such as the new born white tiger cubs. The Daily Mail has more details, so jump on over there once you had your fill on the images.

I just posted about JJ’s novel tool use, and I thought you may wanna see him actually fishing for ants. The authors of the paper provided videos of JJ using his tools. I’ve uploaded it to YouTube for your viewing pleasure.

Even though I’ve been posting a lot on tool use lately, I’m sure you will appreciate this new study. The new study, “Invention and modification of a new tool use behavior: ant-fishing in trees by a wild chimpanzee (Pan troglodytes verus) at Bossou, Guinea,” has been published in the most recent issue of the American Journal of Primatology. The writeup is very simple and informative, which is great because I consider this a very important paper in figuring out the origins of tool use and the intricacies of primate behavior.

The scope of this paper is a report on tool use seen in a male chimpanzee from Guinea. Tool use has been documented in several other wild chimpanzee societies, most notably was Goodall’s observations of Gombe chimps using tools. Since then other researchers have seen other wild chimps use tools, particularly using rocks to crack nuts open, and using twigs and sticks to fish or dip for ants. Ever so recently, we read and saw a Fongoli chimp hunt with a makeshift spear.

The clincher behind chimpanzee tool use in the wild use has been that it seems to be localized within the group that the behavior is observed in. This has gotten many researchers to hypothesize that this is some group specific behavior, a cultural trait per say. Researchers had no idea how tool use behaviors emerged in these respective groups, nor how long they have been practicing tool use.

In this new study, JJ, the male chimpanzee was the only chimpanzee in his group seen selecting for sticks used to fish for ants in a two year time period. This group of chimpanzees from Bossou has been studying for 27 years and this behavior has never been observed before. So his tool use tendencies seem to be novel amongst this group. Throughout the two years of observation, JJ progressively modified the optimal fishing stick, selecting for shorter and shorter ones. This indicates that JJ learned the characteristics of the best tool, one that would yield more ants.

Unfortunately, no observation has been made of JJ transmitting this behavior to other Bossou chimps. But it does indicate several thing… tool use can independently arise in chimpanzees, regardless of the fact that the group as a whole practices tool use or not. Also, it provides an insights into the cognitive capacity of wild chimps, like JJ, to problem solve and modify their behavior.

Yamamoto, S., Yamakoshi, G., Humle, T., Matsuzawa, T. (2008). Invention and modification of a new tool use behavior: ant-fishing in trees by a wild chimpanzee (Pan troglodytes verus) at Bossou, Guinea. American Journal of Primatology DOI: 10.1002/ajp.20544