Evolution Events!

Welcome to episode 5 of Evolution Events! 

Who can guess what our subject is today? Today we look at the interesting species that is the gray whale, and their classification in the modern animal kingdom. 

A gray whale (left image) is a baleen whale, just like the humpback whale (right image) and other species such as the minke whale and fin whale, to name a few. But what is so special about the gray whale in terms of classification? 

The gray whale is the only living member of its scientific family, Eschrichtiidae. There is fossil evidence that other individuals in this family were once present. The Family is believed to have emerged around 10 million years ago. It is key to note that fossil hypotheses and related ancestors, the classification of Family Eschrichtiidae and time of emergence may differ slightly amongst scientific sources. Some classification and evolution of gray whales is still unresolved.  

Today, the modern gray whale, known as Eschrichtius robustus, is organised into two populations, the Eastern and the Western North Pacific populations. The earliest found fossil of this specific genus (meaning the former word of the Latin name, Eschrichtius) was found in Hokkaido, Japan and is believed to be several million years old (between 2-5 million years). 

Gray whales bear a few unique characteristics that separate them from other baleen whales. These include certain characteristics of skull and baleen structure. Among baleen whales, the gray whale is also considered to be the most coastal and utilizes the longest migrations! Gray whales are also fascinating suction-feeders, using their baleen (which is universal to baleen whales) to separate tiny creatures such as crustaceans from muddy seafloor bottoms (not a universal strategy). Though it does have unique qualities as mentioned, gray whales are still closely related to rorquals (scientific Family Balaenopteridae); a group that does include the humpback whale, which is also found in the Salish Sea. 

The Eschrichtiidae family is one of four extant (living) families; the others being Balaenopteridae, Neobalaenidae and Balaenopteridae that make up the fascinating leviathans that are the baleen whales of today.

Article by: Alexa D., B.Sc. / Five Star Naturalist

References (click to view):

Family ESCHRICHTIIDAE (GRAY WHALE), iNaturalist, An early Pleistocene gray whale (Cetacea: Eschrichtiidae) from the Rio Dell Formation of Northern California, Eschrichtiidae, Mingan Island Cetacean Study.