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MAN, THE FIERCEST—AND MOST SHORT-SIGHTED?—PREDATOR

HUMANS ARE hunter-gathers by nature. However, in contrast to other predators, we are also technologists devising improved means of predation. And we are the only predators hunting for trophy or status.

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Science magazine, the weekly publication of the American Association for the Advancement of Science, discussed this in its August 21, 2015, issue. The following is gleaned from “A Most Unusual (Super)predator” by Boris Worm and “The Unique Ecology of Human Predators” by Chris T. Darimont and fellow researchers in B.C., Canada. Abstracts of these are available at Superpredator and Human Predator, respectively.

The researchers analyzed data on 2,135 wild animal populations, both aquatic and terrestrial. The animals were on various trophic levels, herbivores (e.g., anchovy and rabbit), carnivores (mackerel and lynx) and top predators (shark and wolf). The researchers found that humans take up to 14 times as many adult prey as do other predators. By contrast, other predators prey on juveniles or weak members of a species. As noted in Science, “This unique preference, however, has implications for the sustainability of exploitation and even the course of evolution.”

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Unnatural selection: Earnest Hemingway with a prize marlin. This Corbis image and others from Science, August 21, 2015.

Trophy hunters and fishers, it’s noted, target the largest, healthiest and fittest of a species. However, notes Science, “Adult individuals provide the ‘reproductive capital’ of a population, akin to the financial capital in a bank account or retirement fund…. Depleting the capital is risky, particularly in long-lived, late-maturing organisms.”

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Trophy “hunt:” Humans have the ability to hunt for trophies or status from a safe distance. Image by Paula French/Shutterstock.

On land, human predation tends to focus on top predators. (Who would put a rabbit rug before the fireplace?) By contrast, fishing, sport and commercial, is across trophic levels in what researchers call “fishing through marine food webs.”

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Wildlife under pressure. Image adapted by P. Huey/Science.

Human exploitation has ecological effect across species. For example, overfishing off West Africa caused a food scarcity that intensified the hunt for wild meat on land. There’s an observer bias as well, one that’s often beneficial: Animal populations that are studied also tend to be the ones that experience some sort of management.

In summing up “A Most Unusual (Super)predator,” Boris Worm writes, “There are three key insights. First, the hunting of large prey is deeply embedded in our identity and remains a powerful ecological and evolutionary force. Second, the ability to target mostly adult individuals across marine and terrestrial prey groups makes us unique among all other predators.”

On a positive note, “And third, we have the unusual ability to analyze and consciously adjust our behavior to minimize deleterious consequences. This final point, I believe, will prove critical for our continued coexistence with viable wildlife populations on land and in the sea.” ds

© Dennis Simanaitis, SimanaitisSays.com, 2015

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