Savannah: If you crave a nice, cool salad during a heat wave, you're not alone. The fossil record tells us that when temperatures rise, animal diets shift toward eating more plants, and thanks to climate change, temperatures have definitely been rising. And experiments have found that aquatic snails that normally eat both meat and veg tend toward vegetarian diets in higher temperatures. And this is probably true of other animals as well.

Scientists aren't exactly sure why this is but have several thoughts. It could be that animals in colder climes can't meet their metabolic needs eating plants alone but can when temperatures are warmer. The gut bacteria that help break down cellulose work better in hotter temperatures, so it might just be easier to digest plans when it's warm out. Or maybe it's just that animals need more carbohydrates in general as the heat drives up their metabolism.

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