By SINDYA N. BHANOO
JAN. 18, 2016
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A wood rat in front of a creosote bush, its main source of sustenance. Credit Kevin D. Kohl, PhD
Climate change may affect wood rats in the Mojave Desert in a most unusual way. A new study finds that warmer weather reduces their ability to tolerate toxins in the creosote bush, which they rely on for sustenance.
The consequences may be dire for the wood rats. “There’s not much more they can eat out there,” said Patrice Kurnath, a biologist at the University of Utah and one of the study’s authors.
She and her colleagues reported their findings in Proceedings of the Royal Society B: Biological Sciences.
The leaves of the creosote bush contain a resin full of toxic compounds. They are known to cause kidney cysts and liver failure in laboratory rats. Wild wood rats, however, generally tolerate the poisons.
Ms. Kurnath and her colleagues monitored the wood rats as they ate the leaves in warmer temperatures — around 83 degrees Fahrenheit. Although highs in the Mojave can reach the 80s and 90s during the summer, much of the year is cooler. The rats became less tolerant of the toxins and began to lose weight.
The reason may have to do with how the liver functions in warmer weather, Ms. Kurnath said.
The liver is the body’s primary detoxifying organ. When a mammalian liver is active, it increases internal body temperature.
“In warmer weather, maybe you’re not producing huge amounts of heat and you’re not breaking down the toxins,” Ms. Kurnath said.
As the climate warms, the wood rats will disappear from the Mojave or, if they are fortunate, adapt, Ms. Kurnath said.