Big Game Soon To Be Small Game?

New research indicates human hunting and fishing speeds up evolution, leading to smaller organisms

For hunters and fishermen, bragging rights often go to whoever bags the biggest buck or can tell the biggest fish story. But humanity's pursuit of the most physically impressive specimens of any given species might create a paradoxical effect: Research indicates species hunted by humans are getting smaller, faster.

By taking the largest, strongest animals at the peak of their breeding potential, we are speeding up evolution in species harvested by humans up to 300 percent faster than in natural systems. As a result, we're unintentionally breeding smaller deer, fish, and other prized game species. Bighorn sheep have seen an average 20 percent decrease in horn length and body mass in the last three decades—an accelerated trait scientists attribute to the fact that hunters can't shoot sheep unless their horns have reached a certain length.

Commercial fishing has made Atlantic cod smaller, and it's shortened their breeding cycle to five years instead of six. Younger, smaller fish bear fewer eggs, and both the lower numbers and decreased fish size has contributed to the crash in the cod fishing industry. All told, the scientists studied 29 different species of animals and even plants like ginseng to learn that species under harvesting pressure had shrunk by an average of 20 percent.

So are we destined to eventually see miniature deer the size of house cats running through the forest? Not exactly: Scientists theorize that the trend could potentially reverse itself if hunters and harvesters mimicked nature and took smaller, weaker animals instead of the largest, strongest specimens.

I imagine it'll take a long time for fishing and hunting competitions to reverse the trend of awarding prizes for the biggest specimen caught, but I'm personally looking forward to it. I usually catch nothing—does that make me the winner? I think it does.

—Ted Alvarez

Research ties human acts to harmful rates of species evolution (NY Times)