KOMPAS.com – A group of endangered Orcaella brevirostris or popularly known as Irrawaddy dolphins were seen around the Mahakam River in Samarinda in Indonesia's East Kalimantan province.
Their rare appearance was captured in a 54-second bystander video that was circulated on social media.
“This is such a rare event in the Mahakam River,” said Twitter user Syariful Bahri.
Using the handle @BahriBpp, Syariful’s video post on July 20 has been retweeted by nearly 23,000 users as of Wednesday afternoon.
People were questioning whether the aquatic mammal was Mahakam dolphins.
Rr Sekar Mira CH SSi MApp Sc, a mammal expert at the Research Center for Oceanography Studies at the Indonesian Institute of Sciences (LIPI), confirmed that the aquatic mammals caught on camera were indeed Mahakam dolphins.
Mira said the dolphins are popularly known as Irrawaddy dolphins, which belong to the infraorder Cetacea and Delphinidae family.
“[This type of] dolphin is found in coastal areas and rivers,” Mira told Kompas.com on Tuesday, July 21.
Irrawaddy dolphins face threats to their existence around Mahakam River, Mira said, noting this is why people consider the sighting rare. Currently, the freshwater dolphins live in a group around the Mahakam River and are separated from other Irrawaddy dolphins in the coastal areas of East Kalimantan.