Another possibility is that dinosaurs coped with the cold much like many modern-day mammals do, by building up a layer of body fat. Druckenmiller gives the example of moose and caribou, which pile on the weight each summer, then survive on a combination of their fat reserves and low-quality forage in the winter when food is sparse – a strategy which has the added bonus of keeping them warm. "…they do it by basically slowly starving," he says. "There"s no reason why dinosaurs couldn"t have done that."