Mario, Hoopa Troopa, Freckles, Casper, Good Lookin', and Cuddlebug and are just some of their names. They are rhesus macaques, monkeys who sit around all day in small cages, snacking on tasty high-fat treats. In fact, sitting and snacking has become their life's purpose.
They are part of a controversial obesity study at the oldest primate research center in the country, the Oregon National Primate Research Center in Portland, Ore., where researchers are trying to turn 150 monkeys into perfect couch potatoes.
The hope is that studying their bodies will provide clues about human obesity, a condition that affects 70 million Americans.
Dr. Kevin Grove, the neuroscientist leading the research, said that the goal here is to mimic the lifestyle and eating habits of obese people.
"We are trying to model that sedentary lifestyle," Grove said. "That sitting around all day eating tasty treats, sitting in the cubicle at work, eating those snacks all day long...they [the monkeys] will sit there and snack, just like a human will."
Kept in small cages to limit exercise, these monkeys are fattened up with high-fat, high-sugar snacks including peanut butter lard treats and a syrupy sugar drink meant to imitate a human's consumption of a can of soda a day.
"They get about 35 percent of their calories from fat," said Grove.
While most of the monkeys don't look obese to the naked eye, there is one that unmistakably does. His name is Shiva, and he weighs 45 pounds, which is more or less equivalent to a 5-foot 10-inch man who weighs 250 pounds.
Shiva's potbelly drags along the floor of his cage when he moves. Much like the other monkeys at the center, he can't seem to hide his excitement when presented with his next treat. The scientific junk food has taken a toll. Shiva is in a pre-diabetic state.
Under these conditions, the monkeys will often develop obesity-related illnesses. In fact, several of them are full-blown diabetics who depend on their daily insulin shots to survive. According to Grove, diabetic monkeys help researchers understand more about how the illness works in humans.
Just as some obese humans can develop heart conditions, researchers said some of the obese monkeys used in the study will die prematurely from heart attacks or cardiovascular conditions.
Not surprisingly, using monkeys to study human obesity has provoked some outrage. Kathleen Conlee, the Director of Program Management for Animal Research Issues at the Humane Society of the United States, is among the critics and said she has conducted lab research on the same type of monkey in the past.
"How is this any way mimicking a human condition?" she said of the study. "Humans aren't put in isolation and force fed high calorie diets…This is the kind of thing we consider to be frivolous and unnecessary."
But Dr. Grove insisted studying monkeys under these strict conditions is the best way to make strides in obesity research because these primates are so similar to humans in brain function and behavior.
"They model, they develop the disease in the same pattern as humans do," he said.
He said that while studies on obese humans are critical, they are often difficult for a variety of reasons.
"We simply can't control the environment well enough," Dr. Grove said. "It is also important for us to be able to control all aspects of the environment and the disease. Here we can do that."