By Sam Lucas
The order Cetacea houses two distinct groups: toothed whales and baleen whales. Toothed whales make up the majority of cetaceans – there are 67 species of toothed whales and just 11 species of baleen whales found throughout the world’s oceans.
Although not vast in number of species, the baleen whales make up for it with their size. Blue whales, grey whales, and humpback whales are just a few examples of baleen whale species. The blue whale is the largest animal ever known to live on Earth, reaching lengths of 80 to 100 feet!
Baleen whales are named after a unique structure within their mouths. Instead of teeth, they have hundreds of overlapping baleen plates growing downward from their upper jaw. They are arranged in a row, similar to the teeth of a comb, and are composed of keratin. Keratin is the same protein that is found in our fingernails and hair, allowing the baleen to be both flexible and strong.
Image from: https://www.hakaimagazine.com/features/oral-history-toothless-whales/
A baleen whale’s diet primarily consists of zooplankton and small fishes, but can vary among species. To acquire food, whales use a variety of techniques such as skimming, gulping, or sucking water into their large mouths. Once water begins to enter its mouth, the whale begins to expand its throat to accommodate this influx. Then, the whale uses its powerful tongue to force the water through the baleen plates. The baleen plates act as a sifter – water exits the whale, but krill for example, can not. All that is left for the whale to do is to swallow the tasty meal that remains!
In recent years, scientists have discovered that studying baleen can provide insight into the life of whales. Keratin within baleen contains information on the whales’ overall health, movement and reproduction. Scientists are also able to obtain hormonal data and isotope ratios from the baleen. This information can help scientists shed light on environmental conditions, diet and migrations of whales. If you’d like to learn more about this study, please check-out Hakai Magazine.