Recently I saw an article about sled dogs burning 10,000 calories in a day. Even when adjusted for mass, this is significantly more energy than a human athlete might use. This got me thinking: how much energy do bacteria use in a day? Trees? Fungi? Other animals? I can think of lots of variables that will affect energy usage, but I still see no reason why the data couldn't be gathered/compared. So far the only data I've seen is comparing sled dogs to humans, so please post anything you've seen along these lines.