Notable: Hadza foraging by random walk

Notable paper: Raichlen, D. A., Wood, B. M., Gordon, A. D., Mabulla, A. Z., Marlowe, F. W., & Pontzer, H. (2014). Evidence of Lévy walk foraging patterns in human hunter–gatherers. Proceedings of the National Academy of Sciences, 111(2), 728-733.

Synopsis: A Lévy walk is a kind of power distribution in which a single meandering path can be broken down into multiple short steps interspersed with few long steps, separated by changes in direction or pauses. This kind of pattern is called “scale-invariant”, because the interspersal of long and short occurs at every scale. Raichlen and colleagues asked Hadza people to wear GPS devices while foraging for food, finding that 40% of their foraging bouts involved the short-long interspersed pattern of the Lévy distribution, truncated because of the lack of very long segments. A further 40% or more could be accommodated by other mathematical models with long and short steps alternated.

Important because: Some other animals who forage across long distances also use this kind of pattern. So do humans who live in cities. From very simple to complex, the scale-invariant search strategies seem to be the most common.

Interesting aside: Hadza women used the scale-invariant foraging pattern more than men, in large part because men stopped the search pattern when they found meat or honey and traveled more or less straight back to camp.