...common dolphins, which are often seen off South Africa’s east coast, can occur in schools of several thousand. The biggest school on record was estimated to consist of about 15,000 dolphins!
...because whales and dolphins are streamlined to swim in water, they do not have external organs. This makes it almost impossible to tell the sex of a whale or dolphin when watching them on the sea surface.
...there are probably types of cetaceans that are as yet unknown. For example, the Longman's beaked whale is only known from skulls washed ashore in Somalia and Australia. It has never been seen alive!
...in baleen whales females are bigger than males, while in the toothed whales the males are bigger than females.
