The finless porpoise is a close relative of the dolphin, with a leaden body and a lively and cute personality. Adult finless porpoises can reach 1.9 meters in length and are smaller than dolphins, but their brains are as developed as dolphins and their intelligence is similar to that of gorillas. The biggest difference between them is that finless porpoises have no dorsal fin. Finless porpoises, like humans, are viviparous mammals that use lungs to breathe. To distinguish the direction and image of objects in the water, the finless porpoise does not use its eyes, but uses a precise and developed echolocation system, and its round forehead is the key part of this system!