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Of Sharks, Bees And Humans: Hunting Patterns Similar Among Species

December 24, 2013
Image Caption: One of the last hunter-gatherer tribes on Earth, the Hadza people of Tanzania still hunt on foot with traditional foraging methods. “If you want to understand human hunter-gatherer movement, you have to work with a group like the Hadza,” said UA anthropologist David Raichlen, who led the study. Credit: Brian Wood/Yale University

Brett Smith for redOrbit.com – Your Universe Online

A team of international researchers has found that a tribe of hunter-gatherers in Tanzania uses the same search pattern to hunt for food as many other animal species, according to a report published on Monday in the Proceedings of the National Academy of Sciences (PNAS).

The search pattern, also known as the Levy walk, involves a sequence of short travels in one area and then a longer hike to another area. Not just used to find food, the Levy walk can also be seen in the activities of sharks and honeybees.

“This movement pattern seems to occur across species and across environments in humans, from East Africa to urban areas,” said study author Adam Gordon, a physical anthropologist at the University at Albany, State University of New York. “It shows up all across the world in different species and links the way that we move around in the natural world. This suggests that it’s a fundamental pattern likely present in our evolutionary history.”

“Think about your life,” said David Raichlen, an anthropologist at the University of Arizona. “What do you do on a normal day? Go to work and come back, walk short distances around your house? Then every once in a while you take these long steps, on foot, bike, in a car or on a plane. We tend to take short steps in one area and then take longer strides to get to another area.”

“Scientists have been interested in characterizing how animals search for a long time,” he added, “so we decided to look at whether human hunter-gatherers use similar patterns.”

In the study, the researchers equipped tribe members with wristwatch GPS units that tracked their movements. The GPS data revealed that the Hadza have a dominant pattern in their foraging movements: a Lévy walk.

“Detecting this pattern among the Hadza, as has been found in several other species, tells us that such patterns are likely the result of general foraging strategies that many species adopt, across a wide variety of contexts,” said study author Brian Wood, an anthropologist at Yale University.

Although this pattern can be seen in human behaviors, it doesn’t mean that we are guided by it or don’t have our own free will.

“We definitely use memories and cues from the environment as we search,” Raichlen said, “but this pattern seems to emerge in the process.”

The research team said they are currently interested in determining if resource distribution plays a role in determining the Levy walk.

“We’re very interested in studying why the Hadza use this pattern, what’s driving their hunting strategies and when they use this pattern versus another pattern,” said study author Herman Pontzer, a member of the research team and an anthropologist at Hunter College in New York.

“We’d really like to know how and why specific environmental conditions or individual traits influence movement patterns,” Wood said.

Raichlen noted that the understanding of human movement patterns could be used to explain details of our history and how we interact with the environment.

“We can characterize these movement patterns across different human environments, and that means we can use this movement pattern to understand past mobility,” Raichlen said. “Also, finding patterns in nature is always fun.”


Source: Brett Smith for redOrbit.com - Your Universe Online