CHICAGO, Feb 4: Fossils from two early whales — a male and a rare pregnant female — shed light on how these ancestors to modern whales made the leap from walking on land to ruling the sea.

The fetal remains, found with the 47.5 million-year-old pregnant female, were positioned head down, suggesting these creatures gave birth on land, while spending much of the rest of their time in the water.

Initially, the tiny fetal teeth stumped University of Michigan paleontologist Philip Gingerich, whose team discovered the fossils in Pakistan in the years 2000 and 2004.

“When I first saw the small teeth in the field, I thought we were dealing with a small adult whale, but then we continued to expose the specimen and found ribs that seemed too large to go with those teeth,” Gingerich, whose study appears in the Public Library of Science journal PLoS ONE.

The fetal skeleton is the first specimen of the extinct whale group known as Archaeoceti, and the find represents a new species named Maiacetus inuus, a hybrid of the words for ‘mother whale’ and Inuus.

The fetus was positioned head down like other land animals, allowing it to begin breathing right away. This suggests the group had not yet made the leap to giving birth in the water like modern whales, which are born tail first to allow them to start swimming right after birth.—Reuters