Cetacea Order

Whales, dolphins and porpoises are known collectively as cetaceans from the Latin cetus (meaning large see animal) and the Greek ketos (meaning sea monster).

Taxonomy is the scientific name used to define and group living things.  Taxonomy is constantly evolving as our knowledge grows and more is understood about different species, subspecies and populations. But also, of note is that it also changes as species become extinct as its used to describe only living species. Taxonomy classifies whales, dolphins and porpoises as the Order of Cetacea.

The order Cetacea comprises of 96* species of whales, dolphins, and porpoises. It is divided into toothed whales (Odontoceti) of which there are 81* species and baleen whales (Mysticeti) which comprises of 15* species. Within each of these suborders are individual groups or ‘families.’  Each family has a scientific name and a common name. 

It is believed that all marine mammals evolved from land-based ancestors around 50-60 million years ago and that both the baleen and toothed whales diverged from each other around the Eocene period (26 to 17 million years ago) but shared a common ancestor, that is now extinct. The closest living relatives of dolphins today are the even toed ungulates such as camels and cows with the hippopotamus being the closest living relative.

*Correct at the time of writing (January 2023)
Source: WoRMS Editorial Board (2023). World Register of Marine Species. Available from https://www.marinespecies.org at VLIZ. Accessed 2023-01-13. doi:10.14284/170

Cetacea order family tree 

Baleen whales / Mysticeti order family tree 

Toothed whales / Odontoceti order family tree 

click here  to learn more about the delphinadae family

Scholarly links

For more information on this topic please explore these scholarly articles noted below:

•  The Natural History of the Order Cetacea 

•  Taxonomical Consideration on Genera of Delphinidae