About Baleen whales:

• These are any cetacean possessing unique epidermal modifications of the mouth called baleen, which is used to filter food from water.
• Most mammals have teeth in their mouth. Baleen whales are a strange exception.
• Baleen is a large rack of fine, hair-like keratin used to filter out small krill from the water.
• This structure enabled baleen whales to feed efficiently on enormous shoals of tiny zooplankton in productive parts of the ocean, which facilitated the evolution of larger and larger body sizes.
• Baleen whales are generally larger than toothed whales except for the sperm whale which is very big and has teeth.
• Many baleen whales migrate annually, travelling long distances between cold water feeding areas and warm water breeding areas.
• The large whale fossils from Australasia and South America seem to suggest that for most of the evolutionary history of baleen whales, whenever a large baleen whale shows up in the fossil record, it is in the Southern Hemisphere.
• Baleen whales are ecosystem engineers, their huge bodies consuming tremendous amounts of energy.
• Upon death, these whales provide an abundance of nutrients to deep-sea ecosystems.