February 9, 2009

Study: Early whales gave birth on land

A U.S.-led study of the fossil of an extinct pregnant whale discovered in Pakistan suggests primitive whales gave birth on land.

Researchers said the 47.5-million-year-old fossil reveals how primitive whales gave birth and provides new insights into how whales made the transition from land to sea.

The researchers who made the discovery said they were at first perplexed by adult female and fetal bones found together.

When we first saw the small teeth, we 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, said paleontologist Philip Gingerich of the University of Michigan, who led the scientists. By the end of the day, we realized we had found a female whale with a fetus.

He said it is the first discovery of a fetal skeleton of an extinct whale in the group known as Archaeoceti, and the find represents a new species dubbed Maiacetus inuus.

The research that included Munir ul-Haq of the Geological Survey of Pakistan; Wighart von Koenigswald of the University of Bonn in Germany and William Sanders, B. Holly Smith and Iyad Zalmout of the University of Michigan appears in the online journal PLoS One.