real flab: Researchers in the US have found that artificial sweeteners are more fattening than sugar as the consumption of the low-calorie substitutes makes it harder for people to control their intake, as well as body weight. They say sugar can actually be healthier than low-calorie sweeteners as it sends signals to the brain to go for a small intake of food.

to oblivion: Jack rabbits, in the Greater Yellowstone Ecosystem, USA, have disappeared. This could impact other species. No one knows what caused the rabbits to disappear, says the study. It could be disease, extreme weather, predation or other factors. Since the rabbits blipped off without knowledge, there is no way to get at the underlying cause.