Entries in Humans (4)


Chimpanzees vs. Humans: Sizing Up Their Strength

F1online/Thinkstock(WASHINGTON) -- The mauling of Texas graduate student Andrew Oberle by two chimpanzees at the Jane Goodall Institute Chimpanzee Eden in South Africa Thursday was a reminder that in strength, size might not matter.

Chimpanzees are considered the closest living relative of humans, sharing 95 to 98 percent of the same DNA, according to the Jane Goodall Institute in Washington, D.C., a separate entity from the facility in South Africa.

But in no way do humans compare with a chimps' sheer strength and the few percentage points in which the two differ are extreme, many experts say.

"It's the closest thing we know to human warfare" when a chimp is provoked, said Steve Ross, director of the Lester E. Fisher Center for the Study of Conservation of Apes at Lincoln Park Zoo in Chicago. "Chimps are incredibly strong and fast so humans are easily overpowered."

Indeed, chimpanzees have been shown to be about four times as strong as humans comparable in size, according to evolutionary biologist Alan Walker, formerly of Pennsylvania State University. Research suggests the difference in strength between the two lies in the muscle performance. In chimps, the muscles closest to the bones -- those deemed to be the source of strength of both chimps and humans -- are much longer and more intense, so a chimp is able to generate more power using the same range of motion, Ross of the Lester Fisher Center said. The skeletal muscle fibers are much longer and denser, so they can generate more power in the same range of motion.

Also, unlike humans, chimpanzees have less control over their muscles. As a result, sometimes chimps use more of their muscle strength than necessary, according to Walker's theory, published 2009 in the journal Current Anthropology. Such physical lack of control can potentially lead some chimps to become more aggressive when physical. In Thursday's case, however, an internal investigation by the Jane Goodall Institute near Johannesburg showed that the chimps might not have intended to be malicious, Eugene Cussons, director of the institute, told ABC’s Good Morning America today.

The two chimps saw Oberle's crossing the fence into the chimps' space as a violation of their territory, prompting them to take action, Cussons said.

"They have no anger," Cussons said of the chimps. "This is why we come to the conclusion, as far as our expertise goes, that it was a territorial defense. They directed the violence towards Andrew whom they feel was infringing on their territory."

Chimpanzees have a wide range of emotions and they are similar to what humans experience, yet they are known to have erratic and unpredictable impulses, Ross said. The emotional impulses also play a role in how aggressive they can become, he said.

"They can adapt very well to their environment but that doesn't preclude that they are territorial and they are violent and wild animals first," Ross said. "There's an aggression toward individuals that are not in their group."

But chimps are often seen as friendly and cute animals because many facilities use preventive measures to prevent the aggression, he said.

Indeed, the same muscles that are considered to be the source of a chimp's strength can also be seen as a detriment for the animal.  The lengthy muscle fibers mean chimps and other great apes can't swim, Ross said. To protect humans, many zoos create water barriers around the chimps' area so they cannot physically approach, Ross said.

While chimps are most often seen in a zoo environment or in facilities working hand in hand with humans, they are inherently wild and aggressive animals so both trained and untrained individuals should never let their guard down, he added.

"There's never a safe time to be in the same place as a chimp," Ross said. "The natural tendency of chimpanzees is one of aggression and there's always a need among them to demonstrate power and territory."

Copyright 2012 ABC News Radio


'Zoobiquity': 7 Diseases Animals Share With Humans

Stockbyte/Thinkstock(LOS ANGELES) -- Dr. Barbara Natterson-Horowitz is a sort of modern day Dr. Dolittle.

For the past six years, the UCLA cardiologist has been consulting with the Los Angeles Zoo to help treat diseases found in animals. Natterson-Horowitz said she was surprised to learn how much human and veterinary medicine have in common.

"Animals suffer from almost all of the diseases that human beings do, but veterinarians and physicians never talk about this," she said. "Physicians have not typically, traditionally, seen veterinarians as their clinical peers and that's unfortunate."

Her work became the focus of her new book, Zoobiquity: What Animals Can Teach Us about Health and the Science of Healing, which she co-wrote with science writer Kathryn Bowers. The book calls for an approach to medicine that crosses the species barrier. It argues that studying diseases found in both a human and an animal could save both lives.

Natterson-Horowitz's work at the zoo began after she attended a sleepover at the LA Zoo with her young daughter. She struck up a conversation with some of the veterinarians who ended up enlisting her help in cardiac cases.

Here are just seven examples of diseases shared by humans and animals:

1. Heart Disease

One of her first experiences dealing with animal patients came when she examined Cookie the lioness. The big cat had been diagnosed with fluid in the sac around heart -- a potentially fatal condition.

Natterson-Horowitz said what amazed her most was that the zoo veterinarians made Cookie's diagnosis not with a battery of expensive tests -- as they would at UCLA. Instead it was old-fashioned observation, like they used to teach in medical school.

Veterinarians, she said, are the ultimate general practitioners,dealing with a wide range of species including mammals, reptiles and insects. Also, unlike human patients, the animals can't describe their symptoms to their doctors. The vets have to be keen observers.

After that experience, Natterson-Horowitz said she began looking at her human patients differently.

In Zoobiquity, the authors note that animals can experience heart attacks and many species can be frightened to death. Sudden cardiac death, a leading cause of death in humans, can also have "a fear trigger," Natterson-Horowitz and Bowers wrote. However, they also acknowledged that physicians have been "skeptical of linking high emotion and cardiac death in humans."

2. Breast Cancer

According to Natterson-Horowitz and Bowers, certain types of breast cancer have been found a number of mammals.

Their list includes jaguars, cougars, tigers, sea lions, kangaroos, wallabies, beluga whales, alpacas and llamas.

Natterson-Horowitz and Bowers note that the only group of mammals in which breast cancer is rarely found are with the "professional lactators," meaning dairy cows and goats.

3. Skin Cancer

Dr. Curtis Eng, the Los Angeles Zoo's chief veterinarian, said the zoo has come to rely on human specialists like Natterson to help treat its animals.

"There are a lot of medical conditions that we just don't know enough about to treat the animal fully," he told ABC'S Nightline.

So when Rhonda the rhino was diagnosed with squamous cell carcinoma, a common type of skin cancer, on her horn, the zoo brought in one of UCLA's top oncologists. Rhonda even underwent surgery to remove it and is now cancer free.

4. Osteosarcoma

Osteosarcoma, a common type of bone cancer that forced Ted Kennedy Jr. to undergo a leg amputation in 1973, is the leading cause of death in golden retrievers, Natterson-Horowitz and Bowers wrote in their book Zoobiquity.

This disease has also been found in the bones of wolves, grizzly bears, camels, polar bears, some reptiles, fish and birds, according to the authors.

5. Obesity and Diabetes

Zoo animals not only can suffer from obesity, but diabetes is fairly common, in part because the animals eat food that has been genetically modified for human consumption.

In their book, Natterson-Horowitz and Bowers wrote that various animals in the wild will experience binge-eating, secret-eating, nocturnal-eating and food-hoarding, which could suggest a link between humans and "ancestral eating strategies."

6. STDs

Atlantic bottlenose dolphins suffer genital warts, baboons can get herpes, syphilis is rampant among rabbits, just to name a few sexually-transmitted diseases affecting animals that Natterson-Horowitz and Bowers note in their book.

"Wild animals don't practice safe sex," Natterson-Horowitz said. "Of course they get STDs."

In fact, an epidemic of sexually transmitted Chlamydia has devastated koala populations in Australia. Wildlife biologists Down Under are so concerned about it, they are working on a vaccine for Chlamydia in koalas. There is currently no Chlamydia vaccine for humans.

At the same time, Natterson-Horowitz and Bowers wrote that 1 in 4 humans worldwide will die of an STD.

7. Erectile Dysfunction

Horses can experience erectile dysfunction, the authors said. But there's no Viagra for them. Instead vets take a more holistic approach.

"I found that veterinarians are more comfortable talking about the sexuality of their animals then physicians sometimes are," Natterson said. "We are told in medical school to talk with our patients about their sexuality, but sometimes it's easier to talk to a patient about whether they have chest pain walking up a flight of stairs or not, then immediately getting into their sexual life."

Through her research, Natterson-Horowitz said stallions not only have been found to experience erectile dysfunction, they can have sexual dysfunction if they were bred too young or have an upsetting first sexual experience with a mare.

But acknowledging the similarities between humans and animals from a medical perspective does have bigger implications. How does the Zoobiquity approach apply, for instance, to the controversial issue of animal testing?

One could argue Zoobiquity is an argument for more animal testing, because of the similarities among different species, or Zoobiquity could be the basis for a moral argument against animal testing, because we share more in common than we think with the animal kingdom.

Should the Hippocratic Oath -- to do no harm -- apply to hippos? Natterson-Horowitz couldn't say.

"I can't give you a simple answer," she said, "because it's a very complicated, nuanced question."

But, she argued, doctors and veterinarians should have a lot to teach each other.

Copyright 2012 ABC News Radio


New Monkey and Human Adenovirus Breaks the Rules

Comstock/Thinkstock(SAN FRANCISCO) -- Adenoviruses are a type of virus that causes many different infections in humans, monkeys and other animals.  In humans, adenoviruses are responsible for causing a variety of illnesses including cold-like symptoms, diarrhea and pneumonia, but individual types of adenovirus are not known to spread from one species to another -- until now.  

A study conducted at the University of California-San Francisco shows, for the first time, that a single adenovirus infected monkeys, killing most of them, and a human, who then passed on the infection to members of his family.  Thankfully, the infection was milder in humans and only caused an upper respiratory infection with fever, chills and a cough.  

The authors note in their findings, published in PLoS Pathogens, that the virus, though it belongs to the adenovirus family, is unlike any known monkey or human adenovirus and only shares 56 percent of its DNA with its closest viral relative.  

The study's lead author said, “This is clearly a new species of adenovirus and it’s quite different from anything we’ve seen previously…they [the monkeys] are not likely to be the native host species for this virus.  We still don’t know what species is the natural host.”

Copyright 2011 ABC News Radio


Without Language, Playing Field Leveled Between Humans, Primates

Photo Courtesy - Getty Images(ATLANTA) -- With our extensive systems of governance and such global cooperative networks as the United Nations and the World Health Organization, humans are expert cooperators when compared with other animals or even relative primates, such as chimpanzees and capuchin monkeys.

But how much of this cooperation depends on our ability to speak?  Apparently more than you'd believe.  That is the take-away message of a study published Monday in the Proceedings of the National Academy of Sciences.

At the core of the study was a cooperative-rewards game in which participants -- be they man, monkey or chimp -- had to work in pairs.  The game required participants to cooperate to get the biggest payout -- quarters and dollars for the humans, tasty fruit for the primates.  While there was a less-than-ideal cooperation scenario that gave each partner in a pair a quarter, "winning the game" meant figuring out which scenario offered a dollar reward at each round.

When humans were not told the rules of the game and had to figure things out nonverbally, the way their chimp and capuchin monkey primate counterparts had to, human cooperation did not far outperform that of the other primates.

"Normally, we expect to see 100 percent cooperation with humans when they know the rules of the game.  When we had them go in blind, only five pairs out of 26 developed the best scenarios of cooperation.  That's only 20 percent," said lead author Sarah Brosnan, a psychologist at the Language Research Center at Georgia State University.

Humans still outperformed the other primates, who were chosen because they were notoriously cooperative species, but the extent to which the lack of language handicapped the human pairs was surprising, Brosnan noted.

Copyright 2011 ABC News Radio

ABC News Radio