Bighorn sheep are one of many species now documented as getting smaller, on average, due to trophy hunting that targets larger specimens and leaves smaller members of a population, and their genes, to reproduce. Image credit: Paul PaquetFrom Live Science:
Acting as super-predators, humans are forcing changes to body size and reproductive abilities in some species 300 percent faster than would occur naturally, a new study finds.
Hunting and fishing by individual sportsmen as well as large-scale commercial fishing are also outpacing other human influences, such as pollution, in effects on the animal kingdom. The changes are dramatic and may put the survival of some species in question.
In a review of 34 studies that tracked 29 species across 40 different geographic systems, harvested and hunted populations are on average 20 percent smaller in body size than previous generations, and the age at which they first reproduce is on average 25 percent earlier.
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