In scientific classification, whales, dolphins and porpoises are all grouped under the order Cetacea. The word cetacean comes from Greek and translates as “sea monster”. For us, these monsters are all whales. They are divided into two broad groups: toothed whales and baleen whales.
70 vs. 13…
There exist 70 species of toothed whales versus 13 species of baleen whales. What is this huge difference attributable to? Since baleen whales use a highly specialized feeding method, the prey and the habitats that they seek are limited: they require small animals living in large groups. For toothed whales though, there are a million possibilities: prey might be small or large, solitary or gregarious, near the surface or at great depths, near the coast or far offshore, in fresh water or salt water. This broad diversity translates into a large number of habitats, which has been conducive for the diversification of toothed whales.
Solitary or social
Baleen whales are rather solitary. They form pods particularly in the breeding season and in regions where food supplies are abundant. However, several species of toothed whales form complex societies. In belugas, killer whales as well as some species of dolphins, tight bonds are formed between individuals. These social units foster cultural transfer and learning. In baleen whales, the most enduring bonds are those between mothers and their calves. In these species, bonds rarely last more than one year.