A new study on the California gray whale reveals that the key to surviving dramatic changes in the ecosystem was for this whale, at least, the right diet. Adding herring and krill to its diet may have been the gray whale's secret to weathering 120,000 years of climate change.

The study appeared is in PLoS ONE, a science journal published online. By examining current whale DNA, the scientists concluded that there had been little inbreeding, which would have likely occurred if their populations had been greatly reduced by planetary temperature fluctuations. Instead, gray whales have shown a lot more evolutionary plasticity than anyone imagined. Scientists fear that current global warming, blamed on massive carbon emissions by modern society, will have catastrophic affects on global ecological systems. For example, two-thirds of the world's polar bear population could disappear over the next 50 years as sea ice melts, putting them on the path to extinction but based on their past, gray whales could escape such a fate.

The gray whale was once thought to be a bottom-feeder, surviving only on worms and small crustaceans it filtered out of seafloor sediment but if it had relied only on bottom feeding during several high and low temperature periods in the last 120,000 years, its numbers would have been decimated when sea levels in their home territory - the Bering Strait - dropped drastically during the latest cold spell. That drop would have shrunk the seafloor and reduced their food source, but a lack of evidence of a dramatic decrease in their numbers indicated the whales must have adopted other food sources such as krill in order to survive.

The gray whales may be among the winners in the great climate change experiment.The California gray whale population now stands around 22,000. It is now hoped that the research will lead other scientists to delve deeper into the history of different species, especially in the Bering Sea region, because other animals are not expected to weather global warming as easily. The study is in PLoS ONE, a science journal published online.