The four so-called “smiling angels” were carefully selected by researchers of a conservation program led by China's Ministry of Agriculture, which aims to increase the species' numbers by transferring healthy finless porpoises to a safer environment in order to breed. /VCG Photo

The finless porpoise is classified as critically endangered, with only about one thousand left. Despite conservation efforts, their numbers have been decreasing at an annual rate of 13.7%. /VCG Photo