1.- The fruit of a poison tree is armor against hyenas

For a rodent the resembles the love child of a skunk and a steel wool brush, the African crested rat carries itself with surprising amount of swagger.

The rats ''very much have the personality of something that knows it's poisonous,'' says Sara Weinstein, a biologist at the University of Utah and the Smithsonian Conservation Biology Institute, who studies them.

When cornered, they fluff up their fur, including specialized brown hairs with a honeycomb like texture. Those spongy hairs contain a poison powerful enough to bring an elephant to its knees.

In research published in Journal Mammalogy, Dr. Weinstein describes African crested rats chewing bits from poison arrow trees and spitting them back out into their fur.

The chemical protection most likely keeps away predators like hyenas and wild dogs.  The rats are the world's only known toxic rodents and are among the few mammals that borrow poison from plants. [Katherine J. Wu]


2.- Hidden treasure on Hawaii : Rivers running deep underground

There are a few things on the Island of Hawaii more valuable than fresh water. Not because the island    -known to residents of the State of Hawaii as the Big Island - is dry:

There is plenty of rain. But there is tremendous demand, and much of the water disappears before it can be used.

New research by marine geophysicists shows that underground rivers running off the island's western coast are the key to this vanishing act.

Water for human use on the island is often pumped from aquifers. But recent studies have shown that the aquifers are leaking.

''Everyone assumed that this missing fresh water was seeping out at the coastline or traveling laterally along the island,'' said Eric Attias, a postdoctoral researcher at the University of Hawaii, who led the new study published in Science Advances. But his work shows that rivers of fresh water flow underground through porous rock as far as 2 1/2  miles out into the ocean. [Matt Kaplan]


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