The Principal Investigator

A stone-hurling male chimpanzee housed in a Swedish zoo provides the most convincing evidence to date that humans aren’t the only animals capable of planning for the future, according to a study published today (3.09.09) in the journal Current Biology.

Mathias Osvath, of Lund University in Sweden, collected the reports by senior zookeepers at Sweden’s Furuvik Zoo who spent the past decade tracking the behavior of a male chimpanzee named Santino, who regularly threw stones at zoo visitors.

According to Osvath’s study, Santino began to collect and throw stones at zoo visitors shortly after becoming the only male in the zoo’s chimp colony. Shortly thereafter, unbeknownst to Santino, a zookeeper began spying on him in the morning hours before the zoo opened for business.

“In order for a behavior to signal planning for a future state, the predominate mental state during the planning must deviate from the one experienced in the situation that is planned for,” Osvath wrote.

While in hiding, a zookeeper watched as Santino collected stones and pieces of concrete from his outdoor cage, strategically placing in piles facing visitor observation decks. During this time, he did not appear agitated nor did he throw stones, the zookeeper said.

Hours later, however, when zoo patrons arrived, he would launch the ammunition of stones and concrete in the direction of visitors — in an effort to show the zoo patrons who was boss.

In total, the zookeepers said Santino collected stones on 50 separate occasions and shaped stones into easy-to-throw discs on 18 occasions over the years. Conversely, none of the female chimps housed with Santino have displayed similar behaviors.

“Planning, involving toolmaking, reveals a cognitive complexity not apparent in laboratory experiments,” Osvath wrote. “This type of planning with tool making indicates a flexibility associated with mental pre-experience of an upcoming event.”

Previous studies have shown that wild chimps collect and shape sticks to be used for hunting, scientists have been unable to discern whether such behavior meets a immediate or future need.

Despite being unable to fully observe the chimp’s behavior from collection through stone-throwing because of the possible ethical and legal ramifications, Osvath argued that the data show premeditation on the part of chimpanzees. “These observations convincingly show that our fellow apes do consider the future in a very complex way,” he said in a news release. “It implies that they have a highly developed consciousness, including life-like mental simulations of potential events. They most probably have an ‘inner world’ like we have when reviewing past episodes of our lives or thinking of days to come.”

“I think that wild chimpanzees might be even better at planning as they probably rely on it for their daily survival,” Osvath said. “The environment in a zoo is far less complex than in a forest. Zoo chimps never have to encounter the dangers in the forest or live through periods of scarce food. Planning would prove its value in ‘real life’ much more than in a zoo.”

Related links:

Zoo chimp plots stone throwing attacks (MSNBC, 3.09.09)

Study: Belligerent chimp proves animals make plans (AP, 3.09.09)

Missile-throwing chimp plots attacks on tourists (New Scientist, 3.09.09)

Aggressive training techniques may do more harm than good, Penn vets say

Next time you go to pummel your dog for doing something stupid, vets say you’d better think twice. Your aggressive behavior may be exacerbating – not improving – your dog’s aggression, report a team of veterinarians from the University of Pennsylvania.

The results of a year-long survey, published in the February issue of Applied Animal Behaviour Science are based on the survey responses of more than 140 dog owners.

“Nationwide, the No. 1 reason why dog owners take their pet to a veterinary behaviorist is to manage aggressive behavior,” Meghan E. Herron, lead author of the study, said in a news release. “Our study demonstrated that many confrontational training methods, whether staring down dogs, striking them or intimidating them with physical manipulation does little to correct improper behavior and can elicit aggressive responses.”

Researchers administered a 30-item survey to dog owners who were seeking vet assistance for their dog’s behavioral issues at Penn Vet. The survey questions asked owners to reflect on previous training methods used, where they learned of the technique and whether the effect of the training was neutral, positive or negative.

The top confrontational training techniques cited by owners included: “hit or kick dog for undesirable behavior” (43%), “growl at dog” (41%), “physically force the release of an item from a dog’s mouth” (39%), “alpha roll” (31%), “stare at or stare [dog] down” (30%), “dominance down” (29%), and “grab dog by jowls and shake” (26%); such techniques led to an aggressive response in roughly 25 percent of the dogs.

Conversely, dogs that received techniques considered neutral (extra exercise) or positive (extra rewards) to modify behavior showed little aggression.

“This study highlights the risk of dominance-based training, which has been made popular by TV, books and punishment-based training advocates,” Herron said. “These techniques are fear-eliciting and may lead to owner-directed aggression.”

With no hair, beady black eyes and bucked teeth, the naked mole-rat (Heterocephalus glaber) may not be the most attractive rodent in the world. Nonetheless, there’s a reason researchers can’t seem to take their eyes of this wrinkled, underground creature. Scientists believe mole-rats, the longest living rodent in the world, can teach them a thing or two about longevity.

In a study published Monday(2.16.09) in the Proceedings of the National Academy of Sciences (PNAS) scientists say they can now attribute the ability of mole-rats to outlive mice by more than 20 years to their hearty proteins, resistant to attacks by reactive oxygen molecules known to cause oxidative stress, leading to cellular breakdown over time.

“Our data show that [mole-rat] protein structure and integrity are better maintained during aging than that of mice,” the authors of the PNAS study report.

For more than 50 years, researchers believed that differences in rates of aging among species could be explained by the accumulation of cellular damage caused by oxidative stress. The more robust the oxidative damage in a species, the faster aging would take place, scientists theorized.

But, beginning in 2004, researchers studying long-living species of birds, bats and the mole-rats found evidence that contradicted the oxidative stress theory – there was no correlation between oxidative damage and longevity.

“These data suggest[ed] that the oxidative damage, per se, may not effect longevity, but rather resilience to damage and the mechanisms facilitating this may be a far more important determinant of aging,” the authors write.

In an attempt to solve the mystery of longevity in mole-rats, a team of researchers from the San Antonio, New York and Paris joined together to compare groups of young and old mole-rats to age-matched mice, focusing on a select few proteins that researchers recognize as sensitive to oxidative stress.

Aware that proteins, whose intricate twists and folds are critical to function, can become distorted by chronic oxidative stress, researchers set out to see if variations in protein unfolding could explain the aging differences between mole-rats and mice.

Comparative analysis of liver protein samples revealed mole-rats are more resistant to protein unfolding than mice. The authors note, “Even 26-year-old [mole-rats] are better able to maintain protein homeostasis than can young mice.”

The researchers also compared the levels of the protein ubiquitin in mice and mole-rats.  The addition of the small ubiquitin protein to another protein marks the “kiss of death,” alerting the cell to destroy the protein. The ubiquitin levels were similar in young mice and mole-rats, but, as the animals aged, differences in the levels of ubiquitin emerged. While age meant higher levels of ubiquitin for mice, no age-related changes occurred in mole-rats during age 2 to 26, the study authors report.

“Our comparative findings elucidate a key mechanistic difference that may contribute to disparate longevity among species and strongly implicate maintenance of protein stability in successful aging,” the authors conclude.

North American wolves likely have domestic dogs to thank for their dark locks, according to a study appearing online Thursday (2.5.09) in Science.

Though scientists believe that dogs were domesticated between 15,000 and 40,000 years ago in East Asia, the report suggests interbreeding between the playful Native American pups and North American wolves more than 10,000 years ago led to the emergence of wolves with black coats.

“We usually think that dogs developed from wolves,” Stanford geneticist and study co-author Greg Barsh during a Science podcast. “Here’s an example of dogs giving something back to wolves.”

Two genes are credited with the diverse skin, feather and hair shades in nature — agouti controls yellow and red pigments and Melanocortin 1 receptor (Mc1r) controls brown and black. In 2007, Barsh’s lab discovered domestic dogs with black fur such as great Danes, and German shepherds shared a gene called K that, when missing a few pieces of genetic code, works to suppress Mc1r activity, leading to black coats.

Researchers studied the molecular variation at K in hundreds of white, gray and black Yellowstone and Canadian wolves. Of the 113 black wolves surveyed, only two did not have K mutation; none of the 142 white and gray wolves had the mutation.

Though a comparative analysis of the DNA surrounding the black-coat gene in dogs and wolves led researchers to conclude that domesticated dogs were responsible for the emergence of trait in North American wolf population.

“Although genes that evolve under domestication may be transferred to wild species, they generally do not proliferate in the wild because the natural context is so different from that under domestication,” said UCLA evolutionary biologist and study co-author Robert Wayne in a press release. “No one would have guessed that the common black coat color in North American wolves came from dogs — there is no precedent for it. Moreover, for whatever reason, the transfer of the black coat-color gene from dogs to wolves and its success in the wild occurred uniquely in North America.”

Black wolves are relatively rare outside of North America, except for in Italy where there has been a rise in interbreeding between dogs and wolves, according to Barsh. At first glance, the fact that most black wolves inhabit forested regions while steering clear of the open tundra regions seems may seem to suggest coat color selection may act to camouflage wolves from their predators or prey. One problem: wolves don’t have many predators besides humans, of course and even black wolves gray as the age.

The study authors speculate the selective advantage of the black-coat gene likely plays a role in a yet-to-be identified biological process that spans beyond its effect on pigmentation.

“This work shows how domestication can preserve and ultimately enrich the genetic legacy of the original natural populations,” Barsh said in a press release. “Our work is on wolves, but there are many other examples of domestic plants — wheat, rice, maize, soybean — and animals — bison, cattle, cats — where gene flow from domesticated to natural populations has been documented.”