Ann Arbor Times

Variations in environmental temperature and diet can significantly affect the survival abilities of desert rodents against snake venom, according to a recently published study from researchers at the University of Michigan, the University of Nevada Reno, and the University of Utah. The study, led by evolutionary biologist Matthew Holding, was published in Biology Letters.

Holding and his team examined the blood serum of wild woodrats, natural prey of rattlesnakes, to explore their resistance to snake venom. The team found that woodrats exposed to warmer temperatures (29.5°C) demonstrated a stronger ability to neutralize venom compared to those kept in cooler environments (21°C). Holding noted, “That tells us that it’s the actual content of their blood that is changing in response to environmental temperature, and it leads to large differences in the ability of that blood serum to inhibit snake venom.”

Further analysis revealed that diet also plays a significant role in the rodents' venom resistance. Woodrats consuming a natural diet rich in creosote bush, a toxic plant, showed reduced capability to fend off venom compared to those eating basic rat chow. Denise Dearing, a senior author of the study, explained, “If the animals are dedicating energy to staying warm or to digesting a toxic diet, they may have less energy available for producing these venom-resistant proteins.”

The research conducted by Holding, along with colleagues from various institutions, offers insights into the physiological trade-offs rodents face. The team aims to further study which proteins in the woodrat serum are affected by these environmental factors. Holding highlighted the significance of the research, “But it can also lead to the discovery of powerful molecules that may have other important applications.”

The study was supported by funding from the National Science Foundation and the University of Utah, with ethical oversight provided by the University of Utah Institutional Animal Care and Use Committee. Other contributors to the research included Alexandra Coconis and Marjorie Matocq from the University of Nevada Reno, and Patrice Connors from the University of Utah.