Size matters: Extinction risk greatest for smallest and largest animals

BY DAN TAYLOR | PUBLISHED: 09-19-2017

Researchers who evaluated more than 27,000 vertebrate species find that the largest and smallest animals face the greatest risk of extinction.

Researchers who calculated the body masses for thousands of vertebrate species show that animals lucky enough to be neither too big nor too small face a lower risk of extinction that those outside the 'Goldilocks' zone.

The study is published in the Proceedings of the National Academy of Sciences.
"Knowing how animal body size correlates with the likelihood of a species being threatened provides us with a tool to assess extinction risk for the many species we know very little about," said lead author William Ripple, a distinguished professor of ecology at Oregon State University, in a statement.

Ripple and an international team of colleagues evaluated more than 27,000 vertebrate species birds, reptiles, amphibians, fishes, and mammals of which about 4,400 are threatened with extinction.

The main threat facing the largest animals is humans.

"Many of the larger species are being killed and consumed by humans, and about 90 percent of all threatened species larger than 2.2 pounds (1 kilogram) in size are being threatened by harvesting," said Ripple. "Harvesting of these larger animals takes a variety of forms including regulated and unregulated fishing, hunting and trapping for meat consumption, the use of body parts as medicine and killing due to unintentional bycatch."

The smallest species are mostly threatened by loss or change of habitat. Tiny vertebrates weighing less than 3 ounces (77 grams), such as the sapphire-bellied hummingbird, gray gecko, and banana frog, face the highest extinction risk.

Conservation strategies will have to address the threats to the biggest and smallest animals, the researchers say. And while efforts have gone to protecting well-known mammals, such as tigers, whales, and lions, more needs to be done to conserve large non-mammals, including the whale shark, Somali ostrich, and Komodo dragon

 

 

Comments
Laurel Kornfeld - 5 hours ago
Researchers who evaluated more than 27,000 vertebrate species find that the largest and smallest animals face the greatest risk of extinction.
Laurel Kornfeld - 5 hours ago
Researchers who evaluated more than 27,000 vertebrate species find that the largest and smallest animals face the greatest risk of extinction.
Chad Young - 6 hours ago
Researchers who evaluated more than 27,000 vertebrate species find that the largest and smallest animals face the greatest risk of extinction.
Chad Young - 6 hours ago
Researchers who evaluated more than 27,000 vertebrate species find that the largest and smallest animals face the greatest risk of extinction.
Vicky Webb - 6 hours ago
Researchers who evaluated more than 27,000 vertebrate species find that the largest and smallest animals face the greatest risk of extinction.
Paul Pate - 6 hours ago
Researchers who evaluated more than 27,000 vertebrate species find that the largest and smallest animals face the greatest risk of extinction.
Laurel Kornfeld - 6 hours ago
Researchers who evaluated more than 27,000 vertebrate species find that the largest and smallest animals face the greatest risk of extinction.