By Tom Weber, KWMU
St. Louis, MO – Ellie the elephant is due to give birth any day at the St. Louis Zoo, but a key indicator that she's in labor has not yet occurred.
The zoo's Bill Houston says a chemical called progesterone always drops when labor has started. He says until that happens, staffers at the zoo really can't do much.
"And so we just wait for that to occur," he says. "This happens in humans a lot. The only difference between humans and elephants is in humans, we tend to be more cautious, sometimes they'll do a c-section.
"A c-section is not an option with an elephant; never has been."
Last year, Sri the elephant went into labor but tests found her calf was stillborn. Sri is still carrying that calf and should pass it in the next few months.