River dolphins have no predators, except for humans.

淡水河豚没有天敌，除了人类。

youdao

She got her start number-crunching nature with her PhD thesis, a DNA analysis of river dolphins.

她开始她的有关自然的大量运算的博士论文，一篇关于白鳍豚的DNA分析。

youdao

It was at the Mekong, just north of Stung Treng, that I set out to see the Irrawaddy river dolphins, some of the last remaining on the planet.

就是在上丁北面的湄公河上，我看见了在地球上最后幸存的短吻海豚。

youdao

River dolphins of that colour can be spotted in the Amazon River.

BBC: Into Peru��s Amazonian heart of darkness

In the Bolivian forest, the investment is at least protecting the river dolphins, jaguars, caymans and countless bird species which thrive in the park.

BBC: Carbon-trading in Bolivia

This newfound reptile appears to be the first known freshwater mosasaur, an animal comparable to modern river dolphins now seen in the Amazon, Ganges and Yangtze rivers.

MSN: Huge 'sea monster' ruled ancient rivers