The Pygmy sperm whale is one of just two species from the Superfamily Kogiidae, the other one being the Sperm whale. They are seen very rarely, with the majority of the knowledge about them, coming from carcasses that wash up on the beach. It was first described in 1834 based on a skull that washed up on the coast of france in 1784 (50 years earlier). While originally placed in the same genus as the sperm whale, it was moved to its own genus Kogia, as it is actually a species which is half way between the dolphins and the sperm whale.
They grow to around 3.5m, which is smaller than many dolphin species.
It has a far smaller brain than the sperm whale (even by comparison size) which my explain why it has such a lot more simple social life.
Pygmy sperm whales are found throughout the tropical and temperate waters of the Atlantic, Pacific, and Indian Oceans, though there are also seen regularly off Russia. Fossils in Japan, Italy South Africa have been found, suggesting that they were more widely spread. The problem is, that seen rarely at sea, and with most of what we know about coming from carcasses, we have little idea if dead and dying animals behave differently to healthy ones.
Seen rarely, I have been unable to find out how long they can hold their breath, though as the sperm whale can hold its breath for 90 minutes, so its likely that the pygmy sperm whale is also an impressive breath holder – this would explain why they are seen so rarely.