Apes Walking Upright: That's Just How They Roll (or Walk).

Orangutans, gorillas and chimpanzees do it. Bonobos seem to love doing it. Apparently gibbons do it really well. Indeed, bipedalism is not unique to humans and is quite common among apes. Apes are known to walk upright once in awhile, although bonobos seem to do it more frequently than other apes. Bipedalism is just one of the natural repertoire of ape locomotion.

(From left to right) Upright Apes Brigade: Gibbon, Orangutan, Gorilla, Chimpanzee and Bonobo. Click photo for larger image.

Upright Gorilla Goes Viral: 

Ambam the gorilla. Photo from Dailymail.

Currently going viral on the internet is a video of Ambam, a Western lowland gorilla (Gorilla gorilla gorilla) that was filmed walking upright in his enclosure. This 21 year-old, 485 lb. ape currently resides at Port Lympne wild animal park in Kent, England.

If you have not heard of Ambam or caught on to this internet sensation, you can read about him on :
Ambam, the swaggering silverback gorilla who walks around his pen on two legs (DailyMail)
Yes, he can walk. But just how close IS he to being human? (DailyMail)
Walk like a man: Gorilla strolls on hind legs (MSNBC).

It is not uncommon to see a gorilla walk upright but what's unique about Ambam is that he seems to walk upright quite frequently and good at it too. Bipedal locomotion is common in gorillas but they spend most of their time knuckle-walking. Ambam's upright gait and locomotion is definitely not an upright display to intimidate. Instead, it is most probably in response to curiosity and foraging in his enclosure. One of his keeper, Phil Ridges said:

"We think he might use it to get a height advantage to look over the wall when keepers come to feed him and standing up can also help him in looking for food generally in his enclosure as it gives him a better vantage point." Ridges added that Ambam could also carry more food if his hands were freed from walking and it also meant "he doesn't get his hands wet when it is raining."

It seems that the penchant for bipedalism runs deep in Ambam's family. His father, sister and half-sister (same father) prefer to walk upright and stand the same way as Ambam.

Ambam standing upright. Photo from Dailymail.

Is this a novel behavior in response to being in captivity? Is his skeletal and muscular structure (and in some sense his father, sister and half-sister) different than other gorillas? I think it would be interesting to see a behavioral study and an ethogram on Ambam's choice of locomotion. What are the percentage (or time spent) of him walking upright compared to knuckle-walking. Will his offspring be a fan of bipedality as well?

The Other Upright Ape:
While Ambam seem to prefer walking upright once in awhile, there is another ape that came before him who is a habitual biped. This ape is a chimpanzee named Oliver.

Oliver was a media (and science) sensation in the 60s and 70s for his preferred upright locomotion, having 47 chromosomes and a less prognathic face compared to other chimpanzees. Humans have 46 chromosomes while chimpanzees have 48 chromosomes. It was thought that Oliver is a "missing link" between chimpanzees and humans, thus nicknamed the "humanzee". While Oliver is not the missing link (Ely et al.,1998), he is truly a habitual biped.

The 52 year-old Oliver currently resides at Primarily Primates, a sanctuary in San Antonio, Texas. Below is a really good video of Oliver from his early years to his retirement. Seeing what happened to Oliver, I hope that they will not parade Ambam around like a freak of nature.

UPDATE: Oliver passed away on June 2nd 2012 at Primarily Primates. Read more here.

Reference:
Ely, J.J. Leland, M. Martino, M. Swett, W. Moore, C.M. 1998. Technical note: Chromosomal and mtDNA analysis of Oliver. American Journal of Physical Anthropology 105(3) 395-403. DOI: http://www3.interscience.wiley.com/journal/28165/abstract?CRETRY=1&SRETRY=0

Wordless Wednesday

Ape behavior inside the exhibit and holding area

An insightful paper published by Ross et al. (2010), compares zoo-living ape behavior inside their holding and exhibit areas in Lincoln Park Zoo, an accredited member of Association for Zoos and Aquarium (AZA). Zoo animals usually have at least two areas where they are housed (excluding some aquatic animals): the holding area and the exhibit area. During visiting hours and at night, zoo animals are housed in their exhibit area. In the morning, before the zoo opens, they move into the holding area to receive husbandry care and their morning food ration.

The gorilla exhibit area in Lincoln Park Zoo. Photo from Things You Should Do.

One of the chimpanzee from the study, Kipper (now deceased), from Lincoln Park Zoo interacting with a child. Photo by Chicago Tribute.

Holding and exhibit areas differ in size, design and functionality. A study by Ross and Lukas on 11 AZA-accredited zoos shows that holding areas are usually about 40 times smaller than exhibit areas (Ross et al., 2010). At the Lincoln Park Zoo, the holding area is about 9.3% of the size of the exhibit area (for both gorillas and chimpanzees). Whereas the exhibit area is designed for the complexity and to mimic the natural environment of its animal inhabitant, the holding area is usually designed for simplicity and functionality to meet husbandry needs.

Seven gorillas (2 males, 5 females; N = 7) and seven chimpanzees (3 males, 4 females; N = 7) were observed in this study. I should point out that the authors of the study is by no means criticizing Lincoln Park Zoo. It is an informal observation of behavioral changes for these animals in different environment. The result of the study shows that:

Gorillas
Inside the holding area - Increased locomotion and affiliative behavior. Also showed increased rates of aggression, self-directed behavior (subject touches, manipulates or examines the body, skin, or hair) and solitary play. Were in close proximity with each other.

Inside the exhibit area - Increased feeding and foraging behavior and also sexual behavior.

Chimpanzees
Inside the holding area - Increased aggression. Increased rate of scratching and self directed behavior (subject touches, manipulates or examines the body, skin, or hair). Were in close proximity with each other.

Inside the exhibit area - Increased feeding and foraging behavior.

Schematic representation of a typical holding area suite for an individual chimpanzee or gorilla social group at the Regenstein Center for African Apes. Shaded areas indicate animal enclosures; noncolored areas are sections of human activity (caretakers and data collectors). (Ross et al., 2010)

Both gorillas and chimpanzees showed increased aggression accompanied with self directed behavior when inside holding area. Increase in aggression can sometimes be attributed to overcrowding and self directed behavior generally means that an animal is nervous. Being constrained in a smaller space increases the chance of mixed-sex and mixed-dominance encounters thus resulting in agonistic and submissive observations. When inside exhibit areas, both apes exhibited an increase in feeding and foraging behavior. This presumably is due to their feeding and foraging habit in the exhibit area. If I remember correctly, one of the major breakthrough in exhibiting apes (and most animals) is to encourage foraging behavior throughout the day. It is no surprise that these apes exhibit these behaviors.

Chimpanzee subjects in a single enclosure in a holding area suite, during a period of free access (following training and research protocols). Photograph was taken from the central caretaker area. (Ross et al., 2010)

These apes reacted differently when inside their holding area than in their exhibit area because they are exposed to different sensory. Apart from the difference in size and complexity, these two areas also differ in the degree of human interaction, cross-species presence, environmental factors and time spent between these two areas. An understanding of these differences and motivational factors is important in promoting optimized environments for captive apes. The authors encourage that zoos would consider species-specific functional, physical and social preferences when designing enclosures for apes regardless of frequency of use.

Reference:
Ross, S. Wagner, K. Schapiro, S. Hau, J. 2010. Ape behavior in two alternating environments: comparing exhibit and short-term holding areas. American Journal of Primatology 72: 951–959. doi: 10.1002/ajp.20857

Wordless Wednesday

Life Is Good: Baby Gorilla Relaxing In Human-Like Pose

Yewande relaxing in human-like pose. Photo from Telegraph.

This photo was taken at Calgary Zoo, Canada by zoo visitor Nancy Chow. The baby lowland gorilla, a six month old female name Yewande, decided to "chillax" after playing with her favorite pink blanket. Struck by Yewande's pose, Chow took this picture. "When I took this shot I love it right away because the baby gorilla was so adorable, Yewande looks so human-like. It is easy to see how closely we are related to these great apes, Yewande's pose could be any one of us taking a well-earned break. Except I don't think I could do that with my feet", said Chow. Read more on Telegraph: Baby gorilla pictured 'relaxing' in human-like pose.

What a great photo. Thanks to my friend Kambiz for pointing it out that it's blog-worthy. This photo also reminds me of what Dr. Frans de Waal said, "Contrary to general belief, humans imitate apes more than the reverse". So, is this baby gorilla relaxing in human-like pose or are humans relaxing in ape-like pose?

Is Eastern Lowland Gorilla A Hybrid Species?

Over at Lawn Chair Anthropology, Zacharoo discusses whether the Eastern Lowland Gorilla (Gorilla beringei graueri) is a hybrid species of the putative "parental" species, the Eastern mountain gorilla (Gorilla beringei beringei) and the Western lowland gorilla (Gorilla gorilla gorilla). Check out the post, here.

When Is A Monkey Really A Monkey?

A little boy pressed his nose on the glass where a Western Lowland Gorilla is interacting with the zoo-goers. He turns around to his parents with a big smile. “Oh look, the monkey wants to kiss you”, said his mother.

At the lemur exhibit, a girl asks her parents what those black and white primates were. Her dad picks her up and said, “It’s a monkey, sweetie … let’s go”.

A pair of gibbons gracefully swings around in their exhibit. Excited, a group of kindergarteners cheered as these gibbons maneuver around its habitat with great agility. “These monkeys are so active”, said the teacher.

If this sounds familiar to you then you are not alone. I spent a great deal of time near primate exhibits mainly because I love to observe their behaviors. I also enjoy watching interaction between humans and primates. However, there are times when I just can’t control myself and felt compelled to walk over to these people and explain to them that the word “monkey” is not a general term for primates (politely, of course). It shocks me that most of the time people do not read the information panel at the exhibit (aren’t zoo trips for educational purposes?). So when is a monkey really a monkey?

Monkey is a colloquial term for any cercopithecoids (Old World monkey) and platyrrhines (New World monkey). Monkeys are not hominoids (apes) or prosimians. One of the most distinctive characteristic that differentiate monkeys and apes is the presence of a tail in monkeys. Gibbons, siamangs, orangutans, gorilla, chimpanzees and bonobos are apes because they do not have a tail.

Gorillas do not have tails, so they are not monkeys but apes.

Differentiating monkeys and prosimians are a little tricky; all prosimians have grooming claws (toilet claws) but it is generally not visible within zoo exhibits. Prosimians include lemurs, lorises, galagos, aye-ayes and tarsiers.

A ring-tailed lemur is a prosimian. Although it has a tail, it also have grooming claws so lemurs are not monkeys.

A hamadryas baboon is technically a monkey because it has a tail but has no grooming claws.

The Barbary Macaque, Macaca sylvanus, was formerly named Barbary Ape due to the absence of a tail (to be more precise, they have a vestigial tail that looks like a stump). However, we know now that it is more closely related to macaques than to apes so its name was changed to correctly reflect what they are.

A Barbary Ape (notice the lack of tail). Flickr photo from Gerald Davison.

This brings us back to the question, “when is a monkey really a monkey’? The most straightforward answer would be “when it has a tail but doesn’t have grooming claws”. However, the most convenient answer usually lies in front of you … on the information panel.

Flickr photo taken by tim ellis at the Twycross Zoo, England.
The sign reads "Who are you calling a monkey?"

Using Facebook and Twitter to Friend Uganda's Mountain Gorillas

A mountain gorilla. Photo from Stefan Gara

Soon Facebook and Twitter users can "friend" and "follow" Uganda's mountain gorillas (Gorilla beringei beringei) and see videos of them feeding, receive regular updates on the status of these gorillas and even updates on new births.

Lillian Nsubuga, a Wildlife Authority spokeswoman, said that this is to promote Uganda's tourism industry. Aside from Uganda, mountain gorillas can only be found in two other countries; Rwanda and The Democratic Republic of Congo.

Read the full article here.

Homo floresiensis Walked Out of Africa

Skull of LB1 (Homo floresiensis, or the hobbit). Photo from Science Museum

New analysis by a team led by Australian National University doctoral student Debbie Argue showed that Homo floresiensis, nicknamed hobbits, were early hominin and walked out of Africa to Flores. Their findings supports the argument that Homo floresiensis had a unique wrist anatomy that originated from a lineage that lived long before the common ancestor of Homo sapiens and Neanderthals.

With Mike Moorwood from University of Wollongong and Thomas Sutikna from Indonesian Center for Archaeology, Debbie Argue compared 60 skulls and skeletal features from two individual hobbits to those of hominins, chimpanzees and gorillas using cladistic analysis. The result shows that Homo floresiensis "probably took one of two evolutionary paths from Africa to Flores. One began 1.66 million years ago, the other 1.9 million years ago".

Read more here: Hobbits Walked Out of Africa

Humans Evolved From Tree Climbers

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

New Study Suggests That Humans are More Closely Related to Orangutans, Not Chimps

Sorry, been traveling here and there lately so don't really have time to post blog updates. Found this interesting article on EurekAlert!

A new study suggests that humans share a common ancestor with orangutans, not chimpanzees according to shared physical characteristics.

Comparing physical characteristics instead of DNA, researchers Jeffrey H. Schwartz and John Grehan found that humans shared 28 unique physical characteristics with orangutans, share only two features with chimpanzees and seven with gorillas. Humans share seven characteristics with all three apes (chimpanzees, gorillas, and orangutans). Gorillas and chimpanzees shared 11 unique characteristics.

Schwartz and Grehan proposed to have a new "grouping" or classification for humans, orangutans and last common ancestor call "dental hominoids" because they all share similar thick-enameled dental.

Read more about this study at EurekAlert! Humans related to orangutans, not chimps, says new Pitt, Buffalo Museum of Science study.

Great Apes LOL Like Human Too

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.

Roger Wescott's "Upright Display Scenario"

I bet there are some of us out there that wonders how our hominin ancestors started to walk bipedally. They didn't just stood up and walked upright, that's for sure. One good explanation is that they first evolved a bipedal gait, not bipedal locomotion. Many scenarios had been set forth to imagine how the evolution of bipedalism had occurred.

Roger Westcott in 1967 proposed the "Upright Display Scenario" as one of the causes of bipedality, other causes include carrying tools and looking over tall grass while scavenging or predator avoidance. He suggests that bipedal behavior was adaptive because it made the bipedalist appear taller to intimidate their protagonists (other males) and predators. He also suggests that these displays were frequent and impressive. Westcott draws his scenario from threat display behaviors exhibit by the African apes; gorillas and chimpanzees.

Westcott proposed that early hominins had agonistic interactions which includes "two-legged standing or running, probably accompanied by fist-shaking or arm-waving, and possibly involving the seizing and brandishing of sticks or stones" (Parker and Jaffe, 2008).

Chimpanzee upright aggression. Photo from Why Files.

Citation:
Parker S.T. Jaffe K.E. 2008. Darwin's Legacy: Scenarios in Human Evolution. Plymouth, United Kingdom: AltaMira Press.

You're Named After A Cantaloupe

Exams are happening this week so I might not have time to blog. So for the meantime, I'm gonna divert your attention to some cuteness in the primate world.


Isn't he cute? A three-month-old baby gorilla at the San Francisco Zoo is still name-less but not for long. Tomorrow, his father Oscar Jonesy will be given 5 differently colored cantaloupes, each representing 5 different names that were chosen from suggestions around the world. Whichever cantaloupe Oscar picks, that will be the name of the baby. So if you see the baby next time at the zoo, tell him he got his name from a cantaloupe!

*UPDATED 3/11/09 : The baby's name is Hasani, meaning "handsome" in Swahili*

Photo and news from City Insider.

Mirror Mirror On The Wall, Who Is That Other Gibbon?

Gibbons (lesser apes) have no use for mirrors, studies had shown (Suddendorf and Collier-Baker, 2008). They are not able to recognize themselves in front of a mirror. Typical human children starts to recognize themselves in front of the mirror around two-years-old. Mirror self recognition or visual self recognition is not unique to humans, it was only documented in great apes (chimpanzees, bonobos, orangutans and gorillas). Humans and great apes are different than other primates because they can recognize themselves in front of a mirror. Self recognition in front of a mirror enable them to see areas of the body where they cannot see directly. Self recognition probably evolved in the common ancestors of great apes around 18 million years ago.

Primate phylogeny. The ability of mirror self awareness probably evolved around 18 million years ago with great apes (chimpanzees, bonobos, orangutans and gorillas) common ancestors Image from www. mun.ca

A gibbon seems to be interested in itself, but none tried to get at icing on their own faces (Image: Emma Collier-Baker) Photo from www.newscientist.com

The gibbons sometimes tried to reach around the mirror to get at the ape on the other side (Image: Emma Collier-Baker) Photo from www.newscientist.com

Read more about "The evolution of primate visual self-recognition: evidence of absence in lesser apes" by Suddendorf and Collier-Baker, 2008 (full article) (abstract).

"King of the swingers has no use for mirrors" by Ewen Callaway on Newscientist.com

Citation:
Suddendorf T. Collier-Baker E. 2008. The evolution of primate visual self-recognition: evidence of absence in lesser apes. Proceedings of the Royal Society B (doi: 10.1098/rspb.2008.1754 ) http://rspb.royalsocietypublishing.org/content/early/2009/02/21/rspb.2008.1754.full