Warming causing radical changes in wildlife body size
ScienceDaily (Feb. 11, 2010) — Some animals, it seems, are going on a diet, while others have expanding waistlines. It’s likely these are reactions to rapidly rising temperatures due to global climate change, speculates Prof. Yoram Yom-Tov of Tel Aviv University’s Department of Zoology, who has been measuring the evolving body sizes of birds and animals in areas where climate change is most extreme. Changes are happening primarily in higher latitudes, where Prof. Yom-Tov has identified a pattern of birds getting smaller and mammals getting bigger, according to most of the species he’s examined. The change, he hypothesizes, is likely a strategy for survival. Prof. Yom-Tov, who has spent decades measuring and monitoring the body sizes of mammals and small birds, says that these changes have been happening more rapidly. His most recent paper on the topic, focused on the declining body sizes of arctic foxes in Iceland, appeared in Global Change Biology. Animal populations in a wide variety of geographical areas — birds in the UK, small mammals in the arctic, and most recently foxes, lynx and otters in cold Scandinavian regions — are adapting to a shift in rising temperatures. Where temperature changes are most radical, such as those at higher latitudes, Prof. Yom-Tov has measured the most radical changes of these animals’ body size over time. “This change can be seen as an early indicator of climate change,” says Prof. Yom-Tov. “There is a steady increase of temperatures at higher latitudes, and this effect — whether it’s man-made or natural — is having an impact on the animals living in these zones.” In his most recent paper, Prof. Yom-Tov and his Tel Aviv University colleague Prof. Eli Geffen report that arctic foxes are being influenced by changing water currents in the oceans. These changes, likely a result of climate change, affects the foxes’ food supplies. Hydrologists are confounded as to why the shifts in currents are happening, but the effect in foxes is evident: their bodies are changing along with the changing currents. Scientists are finding changes in animals’ bodies across the whole animal kingdom. “Climate change is affecting migration patterns and the behavior and growth of birds, mammals, insects, flowers — you name it,” says Prof. Yom-Tov. “The global warming phenomenon is a fact.” What we do with this information may change our world. …
