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Studying The Science Behind Bullfrog Jumping Abilities

October 17, 2013
Image Caption: Motivation — fear, in this case — appears to contribute to longer jumps. “The frog senses whether you are a scientist hoping it’s going to jump well,” said the scientist, “or a deadly reptilian-like predator who is going to eat it.” Credit: Roberts lab/Brown University

[ Watch the Video: Getting Bullfrogs To Jump For Science ]

Michael Harper for redOrbit.com – Your Universe Online

Physically speaking, bullfrogs should be able to cover more distance in a single hop then they often do.

Scientists have observed such amphibians clearing about four feet per jump, but rarely more than this, while other frog species can travel at more than seven feet per hop. Yet frog jumping contests, such as the world famous Calaveras County Jumping Frog Jubilee, have seen bullfrogs clear this seven-foot mark. One frog, named “Rosie the Ribeter,” leaped into the Guinness Book of World Records in 1986.

One Brown University scientist began to ponder this disparity and became bothered that science couldn’t explain why some bullfrogs can only leap four feet while others nearly double that distance. The answer, says Thomas Roberts, lead researcher of this study, is in the way these competition frogs are motivated.

“It was sort of shocking; we worried about it,” said Roberts of science’s misunderstanding of bullfrog jumps. “Maybe we were missing something but we also had a little bit of uncertainty and skepticism.”

The resulting paper covering Thomas’ research is now published in The Journal of Experimental Biology.

To get to the bottom the these long jumps, Thomas and colleagues had to first observe a certain number of bullfrogs doing what they do best: jumping. They made their way to the County Fair in Angels Camp, California to observe and record “professional” frogs and “rental” frogs. The professional hoppers, of course, were taking part in the competition while the rentals were merely borrowed as a control group. When the pro frogs weren’t competing, Thomas set out grids to accurately measure just how far the frogs would jump. While the research team was able to coerce the rentals into hopping across the grid, the pro frog jockeys insisted on cheering their frogs across. These “jockeys” were intent on working alone and would not allow the researchers to interfere. After recording some 3,124 bullfrog jumps, Thomas and crew retired to the lab to digitize and analyze the leaps.

In the end the rental frogs jumped about 3.6 feet on average per hop, not very close to Rosie the Ribeter’s world record setting leap in the 80s. The professional bullfrogs, on the other hand, were covering nearly 5 feet per hop at the encouragement of their handlers. These jumps didn’t come close to beating the world record, but Thomas was once again left wondering how the results could be so different.

He later deduced that the secret to these long jumps is in the way the jockeys handle these frogs during competition. In his paper, Roberts mentions how every jockey had the same routine before every race. These jockeys always keep their frogs at a warm 84 degrees Fahrenheit and further warm up their legs by rubbing them just before a jump. The jockeys then drop the bullfrogs on the ground for a split second before setting them down again to start the race. Once the race begins, these jockeys lunge at the frogs headfirst, shouting and slapping to move the frogs along more quickly.

“Several of the people mentioned to us that the frog knows the will of the jockey,” said Roberts. “Their point was the frog senses whether you are a scientist hoping it’s going to jump well or a deadly reptilian-like predator who is going to eat it.”

These jockeys also hand pick their frogs and train them to jump farther than they may naturally want to. Thomas says he may be able to get a sample size large enough to find one of these frogs, but he simply doesn’t have the resources.

In closing, Roberts said, “We can order a dozen frogs from our supplier, but a hundred frogs? The animal care bills would bankrupt us!”


Source: Michael Harper for redOrbit.com - Your Universe Online



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