Nutritional contributions of insects to primate diets: Implications for primate evolution

Journal of Human Evolution

Available online 16 April 2014

In Press, Corrected Proof — Note to users

• Jessica M. Rothman^{a, b, c, d, , 1,} ,
• David Raubenheimer^e,
• Margaret A.H. Bryer^{b, c},
• Maressa Takahashi^b,f,
• Christopher C. Gilbert^{a, b, c, d}

http://dx.doi.org/10.1016/j.jhevol.2014.02.016

Abstract

Insects and other invertebrates form a portion of many living and extinct primate diets. We review the nutritional profiles of insects in comparison with other dietary items, and discuss insect nutrients in relation to the nutritional needs of living primates. We find that insects are incorporated into some primate diets as staple foods whereby they are the majority of food intake. They can also be incorporated as complements to other foods in the diet, providing protein in a diet otherwise dominated by gums and/or fruits, or be incorporated as supplements to likely provide an essential nutrient that is not available in the typical diet. During times when they are very abundant, such as in insect outbreaks, insects can serve as replacements to the usual foods eaten by primates. Nutritionally, insects are high in protein and fat compared with typical dietary items like fruit and vegetation. However, insects are small in size and for larger primates (>1 kg) it is usually nutritionally profitable only to consume insects when they are available in large quantities. In small quantities, they may serve to provide important vitamins and fatty acids typically unavailable in primate diets. In a brief analysis, we found that soft-bodied insects are higher in fat though similar in chitin and protein than hard-bodied insects. In the fossil record, primates can be defined as soft- or hard-bodied insect feeders based on dental morphology. The differences in the nutritional composition of insects may have implications for understanding early primate evolution and ecology.

• Insectivory;
• Entomophagy;
• Nutritional ecology;
• Dietary ecology;
• Proteins;
• Fats;
• Euprimates

Biomechanical strategies for accuracy and force generation during stone tool production

Journal of Human Evolution

Available online 18 April 2014

In Press, Corrected Proof — Note to users

http://dx.doi.org/10.1016/j.jhevol.2014.03.004

• E.M. Williams^{a, , , ,} ,
• A.D. Gordon^b, ,
• B.G. Richmond^{c, d,}

Abstract

Multiple hominin species used and produced stone tools, and the archaeological record provides evidence that stone tool behaviors intensified among later members of the genus Homo. This intensification is widely thought to be the product of cognitive and anatomical adaptations that enabled later Homo taxa to produce stone tools more efficiently relative to earlier hominin species. This study builds upon recent investigations of the knapping motions of modern humans to test whether aspects of our upper limb anatomy contribute to accuracy and/or efficiency. Knapping kinematics were captured from eight experienced knappers using a Vicon motion capture system. Each subject produced a series of Oldowan bifacial choppers under two conditions: with normal wrist mobility and while wearing a brace that reduced wrist extension (∼30°–35°), simulating one aspect of the likely primitive hominin condition. Under normal conditions, subjects employed a variant of the proximal-to-distal joint sequence common to throwing activities: subjects initiated down-swing upper limb motion at the shoulder and proceeded distally, increasing peak linear and angular velocities from the shoulder to the elbow to the wrist. At the wrist, subjects utilized the ‘dart-thrower's arc,’ the most stable plane of radiocarpal motion, during which wrist extension is coupled with radial deviation and flexion with ulnar deviation. With an unrestrained wrist, subjects achieved significantly greater target accuracy, wrist angular velocities, and hand linear velocities compared with the braced condition. Additionally, the modern wrist's ability to reach high degrees of extension (≥28.5°) following strike may decrease risk of carpal and ligamentous damage caused by hyperextension. These results suggest that wrist extension in humans contributes significantly to stone tool-making performance.

Dolphin Memories Span at Least 20 Years

Ever been at a party where you recognize everyone’s faces but can’t think of their names? That wouldn’t happen if you were a bottlenose dolphin (Tursiops truncatus). The marine mammals can remember each other’s signature contact whistles—calls that function as names—for more than 20 years, the longest social memory ever recorded for a nonhuman animal, according to a new study.

“The ability to remember individuals is thought to be extremely important to the ‘social brain,’ ” says Janet Mann, a marine mammal biologist at Georgetown University in Washington, D.C., who was not involved in the research. Yet, she notes, no one has succeeded in designing a test for this talent in the great apes—our closest kin—let alone in dolphins.

Dolphins use their signature whistles to stay in touch. Each has its own unique whistle, and they learn and can repeat the whistles of other dolphins. A dolphin will answer when another dolphin mimics its whistle—just as we reply when someone calls our name. The calls enable the marine mammals to communicate over long distances—which is necessary because they live in “fission-fusion” societies, meaning that dolphins in one group split off to join other groups and later return. By whistling, they’re able to find each other again. Scientists don’t know how long dolphins are separated in the wild, but they do know the animals can live almost 50 years. So how long do the dolphins remember the calls of their friends?

To find out, Jason Bruck, a cognitive ethologist at the University of Chicago in Illinois, spent 5 years collecting 71 whistles from 43 dolphins at six captive facilities, including Brookfield Zoo near Chicago and Dolphin Quest in Bermuda. The six sites belong to a consortium that rotates the marine mammals for breeding and has decades-long records of which dolphins have lived together. The dolphins ranged in age from 4 months to 47 years and included males and females. Some of the animals had spent as little as 3 months together; others had been housed with each other for as long as 18.5 years before being separated and sent to another facility; and some had been apart for 20.5 years.

At each facility, Bruck placed a submerged speaker in the dolphins’ pool and waited for one of the animals to swim past. He then played a recording of a whistle that the dolphin had never heard before. “They don’t pay much attention to signature whistles of dolphins they don’t know,” he says. But when he played the whistle of a dolphin they had once lived with, the animals often swam immediately to the speaker. “They will hover around it, whistle at it, seemingly try to get a response,” he says.

Bruck also played recordings of an unfamiliar dolphin that was the same age and sex as the familiar animal—but these also did not elicit much of a response. “It was a striking pattern,” Bruck says. “They were potentially bored by unfamiliar calls but responded to whistles from the animals they’d known,” even if they had not heard the whistles in decades. “It seemed to be stimulating to them. In Bermuda, a mother dolphin even brought her calf over to listen to the whistles of dolphins she’d known,” Bruck says. Sometimes the dolphins got upset, slapping their tails in protest, when Bruck removed the speaker from the pool; but they quickly settled down again after he put it back in the water.

In one case, Bruck played the whistle of Allie, a female dolphin at the Brookfield Zoo, for Bailey, a female in Bermuda. They had lived together at the Dolphin Connection in the Florida Keys when Allie was 4 and Bailey was 2. Twenty years and 6 months had passed—yet Bailey instantly recognized Allie’s whistle, Bruck says, as evidenced by her close attentiveness to the speaker.

The dolphins often responded as if they were picturing their long-ago social pals, Bruck reports online today in the Proceedings of the Royal Society B. For instance, two younger dolphins, Kai and D.J., became watchful and alert when they heard the whistles of Lucky and Hastings, two dominant males they had spent time with at the Brookfield Zoo. “Their whistles elicit a certain vigor and spirit in males that hear them,” says Bruck about the responses of Kai and D.J. “It looked as if those whistles put the image of those two dominant males in the heads of Kai and D.J.,” although he adds this has yet to be shown experimentally.

The study demonstrates the “long-term stability of the dolphins’ whistles,” Mann says. “Even though dolphins may change in size and physical characteristics—getting scars and speckles—their whistles provide a reliable means of identification.” And that in turn enables them to “track relationships and connections between individuals,” she says. 

“We know they have relationships in the wild that last decades,” adds Richard Connor, an animal behaviorist at the University of Massachusetts, Dartmouth. “Remembering a particular individual—even in the absence of that individual—could help them navigate their current social milieu.”

Bruck’s study, however, did not test whether the dolphins mentally picture the correct dolphin when they hear his or her signature whistle. So far, scientists have only been able to demonstrate this ability in horses. Researchers from the University of Sussex in the United Kingdom videoed individual horses while a herd member was led past them and out of view. The scientists then played the whinny of that horse or of a different horse. If the whinny was from the horse that had just walked by, the watching horse continued doing whatever it had been doing before; but if the whinny came from a different stable-mate, the watcher instantly turned to look in the direction of the call, as if saying, “that didn’t sound like you.”

A similar experiment now needs to be done with dolphins, says Stephanie King, a biologist at the University of St. Andrews in the United Kingdom. She wonders if the animals are paying attention to the whistles of their former pool-pals because the sounds are familiar—or because they “evoke a mental representation of the absent animal in the dolphin’s mind.” In other words, does Kai mentally picture Lucky when he hears the dominant male’s brassy whistle erupting from the speaker? Or does he merely register, “That call takes me right back to Chicago.” Stay tuned—Bruck has a test in the works to find out.

ScienceMag

Dogs yawn more often in response to owners' yawns

Dogs yawn contagiously when they see a person yawning, and respond more frequently to their owner's yawns than to a stranger's, according to research published August 7 in the open access journal PLOS ONE by Teresa Romero and colleagues from the University of Tokyo.

Pet dogs in the study watched their owner or a stranger yawn, or mimic a yawning mouth movement, but yawned significantly more in response to their owners' actions than to the strangers' yawns. The dogs also responded less frequently to the fake movements, suggesting they have the ability to yawn contagiously. Previous research has shown that dogs yawn in response to human yawns, but it was unclear whether this was a mild stress response or an empathetic response. The results of this study suggest the latter, as dogs responded more to their owners' genuine yawns than those of a stranger. The researchers observed no significant differences in the dogs' heartbeat during the experiments, making it unlikely that their yawns were a distress response.

Explaining the significance of the results, Romero says, "Our study suggests that contagious yawning in dogs is emotionally connected in a way similar to humans. Although our study cannot determine the exact underlying mechanism operative in dogs, the subjects' physiological measures taken during the study allowed us to counter the alternative hypothesis of yawning as a distress response.

More information: Romero T, Konno A, Hasegawa T (2013) Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy. PLOS ONE 8(8): e71365. doi:10.1371/journal.pone.0071365

Journal reference: PLoS ONE

Read more at: http://phys.org/news/2013-08-dogs-response-owners-strangers.html#jCp

Chocolate may help keep brain healthy

MINNEAPOLIS – Drinking two cups of hot chocolate a day may help older people keep their brains healthy and their thinking skills sharp, according to a study published in the August 7, 2013, online issue of Neurology®, the medical journal of the American Academy of Neurology.

The study involved 60 people with an average age of 73 who did not have dementia. The participants drank two cups of hot cocoa per day for 30 days and did not consume any other chocolate during the study. They were given tests of memory and thinking skills. They also had ultrasounds tests to measure the amount of blood flow to the brain during the tests.

"We're learning more about blood flow in the brain and its effect on thinking skills," said study author Farzaneh A. Sorond, MD, PhD, of Harvard Medical School in Boston and a member of the American Academy of Neurology. "As different areas of the brain need more energy to complete their tasks, they also need greater blood flow. This relationship, called neurovascular coupling, may play an important role in diseases such as Alzheimer's."

Of the 60 participants, 18 had impaired blood flow at the start of the study. Those people had an 8.3-percent improvement in the blood flow to the working areas of the brain by the end of the study, while there was no improvement for those who started out with regular blood flow.

The people with impaired blood flow also improved their times on a test of working memory, with scores dropping from 167 seconds at the beginning of the study to 116 seconds at the end. There was no change in times for people with regular blood flow.

A total of 24 of the participants also had MRI scans of the brain to look for tiny areas of brain damage. The scans found that people with impaired blood flow were also more likely to have these areas of brain damage.

Half of the study participants received hot cocoa that was rich in the antioxidant flavanol, while the other half received flavanol-poor hot cocoa. There were no differences between the two groups in the results.

"More work is needed to prove a link between cocoa, blood flow problems and cognitive decline," said Paul B. Rosenberg, MD, of Johns Hopkins School of Medicine in Baltimore, who wrote an editorial accompanying the study. "But this is an important first step that could guide future studies."

Eurekalert

Inca children were drugged with coca and alcohol before sacrifice

Scientists from the Department of Forensic Medicine at the University of Copenhagen have examined the bodies of three 500-year-old Inca children along with scientists from Bradford University in England. This has given new, detailed knowledge about the old Ince ritual 'capacocha' which also involved sacrificing humans. The results were published recently in the journal PNAS.

One of the examined mummies is the 13-year-old girl, 'The Llullaillaco Maiden', named after the 6,379 meters tall volcanic mountain, Llullaillaco, where she was found frozen close to the mountain's top. The two other bodies are a boy and a girl around 4 or 5 years old found in separate graves near The Maiden. The mummified bodies are all remarkably well-preserved and have been frozen for nearly 500 years near the top of the mountain, which is found on the border between Chile and Argentina.

"Now we know more precisely what happened in an Inca sacrifice, for example to what extent coca and alcohol were used as part of the Inca ritual in the months and weeks preceding a sacrifice. It is very satisfactory that we with our scientific methods can help uncover the unique circumstances regarding a number of very central aspects of ancient Inca culture," says Professor Niels Lynnerup from The Department of Forensic Medicine, who, along with PhD student Chiara Villa, has analysed a number of CT scans of the mummies.

New light on Inca child sacrifice

What we have known so far about the religious capacocha ritual from the Inca Empire, was derived from written sources from the Spanish colonial power in South America. The new analyses of the frozen bodies give new knowledge about the practice of the rituals, for example the child sacrifices.

The scientists' analyses show that the three mummified children had all ingested both coca and alcohol prior to their death. The girl, 'The Maiden', was even found with chewed coca leaves in her mouth, and the analyses show that her consumption of coca increased sharply twelve months before her death, and then peaked six months later. The analyses also show that her alcohol consumption peaked during the last few weeks before her death.

"We made CT analyses and have produced three-dimensional visualisations of the mummified girl's organs and the contents of her mouth cavity. From that we could establish her age relatively precisely just as the coca leaf stuck between her teeth and in her cheek also could be identified. Finally, because of the amazing preservation we could also determine the contents of the intestines, and thereby establish a reasonable time of her final meal," explains Niels Lynnerup.

The other examinations show a significant consumption of cocaine from coca leaves and alcohol in the time leading to the sacrifice. Compared to analyses of her hair this creates a good picture of her life in the two years before her death.

"We can see that the ritual sacrifice has been prepared for a long time and that sustained consumption of drugs apparently was a part of the preparations prior to the sacrifice itself," says Niels Lynnerup.

Ritual use of cocaine and alcohol

Dr. Andrew Wilson is an associate professor at the Department for Forensic and Archaeological Sciences at University of Bradford. He compares in value the new research results with the historic accounts from the Spanish colonial time.

The scientists can with some certainty say that 'The Maiden' was selected as sacrifice twelve months before her death. Also, she was most likely implicated in a number of rituals involving use of coca and alcohol, and both drugs were given to her under supervision for some time.

There was apparently no indication of physical violence against the children, but coca and alcohol have most likely precipitated their death, which was inevitable in the altitudes where they were found.

The circumstances during her final few weeks with 'The Maiden' showing consistently increased levels of coca and alcohol consumption compared the younger children show that there must have been a need to sedate her in the last weeks of her life.

This conclusion is verified by the position in which 'The Maiden' was found. Hun was found sitting cross-legged with her head sloping forward and her arms resting loosely on her lap. Her head piece was intact and the objects surrounding her were undisturbed. This leads the scientists to believe that she was placed in the tomb, heavily influenced by drugs.

Eurekalert

High Tooth Replacement Rates in Largest Dinosaurs Contributed to Their Evolutionary Success

Rapid tooth replacement by sauropods, the largest dinosaurs in the fossil record, likely contributed to their evolutionary success, according to a research paper by Stony Brook University paleontologist Michael D'Emic, PhD, and colleagues. Published in PLOS ONE, the study also hypothesizes that differences in tooth replacement rates among the giant herbivores likely meant their diets varied, an important factor that allowed multiple species to share the same ecosystems for several million years.

Paleontologists have long wondered how sauropods digested massive amounts of foliage that would have been necessary for their immense sizes. In "Evolution of high tooth replacement rates in sauropod dinosaurs," the team of paleontologists reveal that their new research into the microscopic structure of sauropod teeth shows the dinosaurs formed and replaced teeth faster than any other type of dinosaurs -- more like sharks and crocodiles -- and this process kept teeth fresh given the immense amount of wear they underwent from clipping off enormous volumes of food required for them.

"The microscopic structure of teeth and bones records aspects of an animal's physiology, giving us a window into the biology of long-extinct animals," said Dr. D'Emic, Research Instructor in the Department of Anatomical Sciences at Stony Brook University School of Medicine. "We determined that for the gigantic sauropods, each tooth took just a few months to form. Effectively, sauropods took a 'quantity over quality' approach."

Dr. D'Emic explained that unlike mammals and some other dinosaurs, sauropods did not chew their food. They snipped food into smaller pieces before swallowing.

"At least twice during their evolution, sauropods evolved small, peg-like teeth that formed and replaced quickly," said Dr. D'Emic. "This characteristic may have led to the evolutionary success of sauropods."

The team developed a novel method to estimate sauropod tooth formation and replacement rate without destructively sampling the teeth by making microscopic sections. Using these estimates, the researchers could track the evolution of tooth formation and replacement rates through time in species whose fossil remains are too rare to section.

With computed tomography (CT) scanning and microscopic anatomical methods, they measured tooth formation time, replacement rate, crown volume and enamel thickness in sectioned teeth of Camarasaurus and Diplodocus, two dinosaurs from the Late Jurassic Formation of North America. The technology and method enabled the researchers to count the number of growth lines in each tooth. Growth lines are a fraction of the thickness of a human hair. A tally of the lines gives the formation of each tooth in days.

To find out how fast these teeth were replaced, D'Emic and colleagues subtracted the ages of successive teeth from one another. The results indicated that replacement in these animals was extremely fast.

"A nearly 100-foot-long sauropod would have had a fresh tooth in each position about every one to two months, sometimes less" said Dr. D'Emic.

The tooth replacement rate, size and shape data collected by the team indicates that despite their somewhat stereotyped body plan and large body size, sauropods exhibited varied approaches to feeding. The paper indicates that this variation "represents a potential factor that allowed multiple giant species such as Camarasurus and Diplodocus to partition the same ecosystem."

Dr. D'Emic added that the research also contributes to a new view of sauropods, which were once thought to be more primitive than other dinosaur groups such as horned and duckbilled dinosaurs.

The paper co-authors include John Whitlock of Mount Aloysius College, Kathlyn Smith of Georgia Southern University, and Jeffrey Wilson and Daniel Fisher of the University of Michigan.

The dinosaur specimens used for the research were loaned to the paleontologists from the Yale Peabody Museum, Utah Museum of Natural History, Staatliches Museum für Naturkunde and the Iziko South African Museum.

Sauropod Dinosaur Facts:

1. Sauropod dinosaurs were the largest animals that ever walked the land.

2. Familiar examples of sauropods are Diplodocus, Brachiosaurus, and Apatosaurus. Apatosaurus was formerly called "Brontosaurus." These are genera (plural of genus) and should be italicized.

3. Sauropods had tiny heads for their bodies -- even a 100-foot-long animal would have a head only slightly larger than that of a horse.

4. Along with their tiny heads, sauropods had tiny teeth, ranging from the diameter of a pencil to a wide marker and only a few inches long.

5. Sauropods did not chew their food, but clipped it and swallowed it, where it was broken down in their digestive system.

6. In living animals, daily incremental lines are laid down in teeth. These lines are thinner than a human hair. The total number of lines indicates how long it took for the tooth to form.

7. Most animals have only one or two replacement teeth in a given socket (or tooth position), but sauropods had up to nine.

8. Sauropod teeth formed quickly -- in just a few months.

9. Sauropods replaced their teeth more quickly than most animals, including other dinosaurs. A new tooth was replaced in each tooth position every month or so.

10. Sauropods twice evolved small teeth that formed and replaced quickly.

Journal Reference:

1. Michael D. D’Emic, John A. Whitlock, Kathlyn M. Smith, Daniel C. Fisher, Jeffrey A. Wilson. Evolution of High Tooth Replacement Rates in Sauropod Dinosaurs. PLoS ONE, 2013; 8 (7): e69235 DOI: 10.1371/journal.pone.0069235

Source: ScienceDaily

Astronomers Discovery a Graveyard for Comets

A team of astronomers from the University of Anitoquia, Medellin, Colombia, have discovered a graveyard of comets. The researchers, led by Anitoquia astronomer Prof. Ignacio Ferrin, describe how some of these objects, inactive for millions of years, have returned to life leading them to name the group the 'Lazarus comets'.

The team publish their results in the Oxford University Press journal Monthly Notices of the Royal Astronomical Society.

Comets are amongst the smallest objects in the Solar System, typically a few km across and composed of a mixture of rock and ices. If they come close to the Sun, then some of the ices turn to gas, before being swept back by the light of the Sun and the solar wind to form a characteristic tail of gas and dust.

Most observed comets have highly elliptical orbits, meaning that they only rarely approach the Sun. Some of these so-called long period comets take thousands of years to complete each orbit around our nearest star. There is also a population of about 500 short period comets, created when long period comets pass near Jupiter and are deflected in orbits that last anything between 3 and 200 years. Although uncommon events, comets also collide with Earth from time to time and may have helped bring water to our planet.

The new work looked at a third and distinct region of the Solar System, the main belt of asteroids between the orbits of Mars and Jupiter. This volume of space contains more than 1 million objects ranging in size from 1 m to 800 km. The traditional explanation for asteroids is that they are the building blocks of a planet that never formed, as the movement of the pieces was disrupted by the strong gravitational field of Jupiter.

In the last decade 12 active comets have been discovered in the asteroid main belt region. This was something of a surprise and the Medellin team set out to investigate their origin. The team, made up of Prof. Ferrin and his colleagues Profs. Jorge Zuluaga and Pablo Cuartas, now think they have an explanation.

"We found a graveyard of comets," exclaims Professor Ferrín. He adds: "Imagine all these asteroids going around the Sun for aeons, with no hint of activity. We have found that some of these are not dead rocks after all, but are dormant comets that may yet come back to life if the energy that they receive from the Sun increases by a few per cent."

Surprisingly, this can happy fairly easily, as the orbits of many objects in the asteroid belt are nudged by the gravity of Jupiter. The shape of their orbits can then change, leading to a decrease in the minimum distance between the object and the Sun (perihelion) and a slight increase in average temperature.

According to this interpretation, millions of years ago the main belt was populated by thousands of active comets. This population aged and the activity subsided. What we see today is the residual activity of that glorious past. Twelve of those rocks are true comets that were rejuvenated after their minimum distance from the Sun was reduced a little. The little extra energy they received from the Sun was then sufficient to revive them from the graveyard.

Prof. Ferrin describes the 12 active comets. "These objects are the 'Lazarus comets', returning to life after being dormant for thousands or even millions of years. Potentially any one of the many thousands of their quiet neighbours could do the same thing."

S: ScienceDaily

Does Happiness Increase As We Get Older?

Question: Do we get sadder as we get older?

Answer: It seems that just the opposite is true. There's a lot of evidence that we get happier the older we get.

A Gallup telephone poll of 340,000 people across the U.S. showed that happiness comes with age. However, the poll didn't uncover the cause of this phenomenon.

Dr. Arthur A. Stone, a professor of psychology at the State University of New York at Stony Brook, was the lead author of a study based on the Gallup survey. He speculated on the causes for this happiness.

"It could be that there are environmental changes, or it could be psychological changes about the way we view the world, or it could even be biological — for example brain chemistry or endocrine changes," Dr. Stone told the New York Times in 2010.

The telephone survey included people between 18 and 85. The survey showed that people start out at age 18 feeling pretty good. However, they feel progressively worse until they hit 50.

But after that point, people begin getting happier as they age. By the time they are 85, they are even more satisfied with themselves than they were at 18.

Why are older people happier? I collected some theories. Older people are happier because they have:

• A deeper appreciation of the value of life
• A feeling of fulfillment
• A greater ability to understand and handle life's vicissitudes
• Fewer aspirations and expectations of themselves
• The ability to live in the present and not worry about the future
• The wisdom to know they can't please everyone all the time
• An inclination to see situations more positively

A University of Chicago study also showed that happiness increases with age. The researchers asked a cross section of Americans how happy they were. The question was administered in face-to-face interviews of population samples that ranged from about 1,500 to 3,000.

The Chicago researchers theorized that older people are happier because with age comes positive psychosocial traits, such as self-integration and self-esteem; these signs of maturity could contribute to a better sense of overall well-being.

"Older people are better able to recognize what will bother them, and better able to negotiate their environment," said Susan Turk Charles, a psychologist at the University of California, Irvine.

One study looked at people's positive and negative emotions over the course of 23 years, and compared participants by age group. Researchers found that teenagers most frequently reported negative emotions, while octogenarians seemed to feel the least negative.

If you would like to read more columns, you can order a copy of "How to be a Healthy Geezer" at www.healthygeezer.com.

All rights reserved © 2013 by Fred Cicetti

S: Livescience

Strange Ancient Ape Walked on All Fours

A bizarre ancient ape whose gait has stumped researchers for decades walked on all fours and swung from the trees, new research suggests.

The lumbar regions of the O. bambolii fossil
Credit: Liza Shapiro, Gabrielle Russo

Oreopithecus bambolii, an ape that lived on an isolated island 7 million to 9 million years ago in what is now Tuscany and Sardinia, Italy, didn't have the pelvis or spine necessary for regular upright walking, the researchers said. Rather, the beast traversed Earth on all fours.

Their conclusion, detailed online July 23 in the Journal of Human Evolution, overturns an earlier hypothesis that the mysterious ape independently evolved bipedal, or two-legged, walking.

Ape oddity

When O. bambolii was alive, Italy formed a string of islands that were covered with swampy forests and teeming with crocodilians. The ape went extinct after a land bridge connected their island to other land, allowing large saber-toothed cats and other predators to stalk the island.

But the strange creature was a bit of a mystery: Scientists couldn't decide whether it was an ape or a monkey. (Apes have longer arms for swinging through trees, and monkeys often have tails that let them grab branches). O. bambolii had apelike arms, odd teeth with ridges more like a monkey's and feet that each had one backward-pointing toe, similar to those found on birds. [Image Gallery: Our Closest Human Ancestor]

"It's always been a kind of controversial beast. It's an ape that's not closely related to any living apes at all," said William Jungers, a physical anthropologist at Stony Brook University in New York who was not involved in the study.

In the 1990s, one group of researchers took a second look at O. bambolii's pelvis and spine, and concluded the animal had adapted to walk on two legs.

That was a bold claim.

Because no other mammals, aside from humans and their ancestors, routinely walked upright, anthropologists use bipedal adaptations to determine which fossil apes are in humans' direct evolutionary lineage, said study co-author Liza Shapiro, an anthropologist at the University of Texas at Austin.

If O. bambolii, which isn't considered a direct ancestor to humans, had independently evolved upright walking, that line of logic would have to be rethought.

"It would be really extraordinary to see an animal we don't think is closely related to us who got around this way," said William Sanders, a paleoanthropologist at the University of Michigan who was not involved in the study.

Second look

Shapiro and her colleague Gabrielle Russo, an anatomist at Northeast Ohio Medical University, decided to take a second look at O. bambolii.

The team carefully analyzed a fossilized Oreopithecus skeleton that was discovered by a French paleontologist in 1872.

Prior research suggested this specimen had a wider pelvis compared with apes' and a unique lower-back curvature called lordosis. Both of these features give humans better balance when walking upright.

But Shapiro's team looked at the skeleton from several perspectives and found no evidence of these changes: no lower-back curvature and no widening of the pelvis. It also lacked the distinctive widening of vertebrae at the base, which allows the human spine to stack like a pyramid and efficiently direct force into the pelvis.

The team concluded that O. bambolii wasn't a two-legged walker. Instead, it probably used its long, hanging arms and apelike spine to swing from the branches in a forest.

Earlier work had probably drawn different conclusions because the specimen's spine was crushed and distorted, Sanders said.

The new study should put the debate to rest, he said.

That doesn't mean the ancient ape never walked on two legs — just that it wasn't its dominant mode of transport.

"A chimpanzee with an armful of bananas can stand up on two legs and run quite a distance," Sanders told LiveScience. "But that's not a habitual bipedality."

S: Livescience