Study author Nicholas Skopal told Newsweek that they have "only scratched the surface of the stone jar sites, and there must be more."
The last remaining freshwater dolphin on a stretch of the Mekong died after its injuries prevented it from hunting.
The last documented individual was killed by a hunter in 1990.
"The birth of this male is great news for the species," senior zoo keeper Jane Marshall said.
Megalithic jars were found in 15 sites the Southeast Asian nation of Laos.
Obama will become the first sitting president to visit the small nation when he joins global leaders for an Asian summit.
The famed CIA officer served while the U.S. and Soviet Union fought proxy wars in Southeast Asia.
A new study says malaria is resisting the most effective drugs in Southeast Asia.