It takes a lot of energy to grow a baby; just ask anyone who has been pregnant. But scientists are only now discovering just how much. In a study published May 23 in the journal Science, Australian researchers estimated that a human pregnancy demands almost 50,000 dietary calories over the course of nine months. That’s the equivalent of about 50 pints of Ben and Jerry’s Cherry Garcia ice cream, and significantly more than the researchers expected.
“Folks were just poodling along, collecting their data on their species, but no one was putting it together,” Marshall said. By aggregating such data, the researchers estimated the costs of reproduction for 81 species, from insects to snakes to goats. They found that the size of an animal has a big influence on how much energy it needs to reproduce. Microscopic animals called rotifers, for example, require less than a millionth of a calorie to make one offspring.