 Remingtonocetids lived in the Middle @-@ Eocene in South Asia , about 49 to 43 million years ago . Compared to family Pakicetidae and Ambulocetidae , Remingtonocetidae was a diverse family found in north and central Pakistan and western India . Remingtonocetids were also found in shallow marine deposits , but they were obviously more aquatic than ambulocetidae . This is demonstrated by the recovery of their fossils from a variety of coastal marine environments , including near @-@ shore and lagoonal deposits . According to stable oxygen isotopes analysis , most remingtonocetids did not ingest fresh water , and had hence lost their dependency on fresh water relatively soon after their origin . 
