Baleen Whales

There are over 90 species of whales roaming every ocean habitat.  There are two broad classifications of whales, baleen whales and toothed whales.  Baleen whales lack teeth.  When they open their mouths, a membrane made of keratin, called baleen, stretches from the upper to the lower jaw.  This allows water to flow through its porous structure while trapping fish and zooplankton, small sea creatures, by the mouthful.  Toothed whales have actual teeth and they hunt fish, squid, and other animals of the sea.

^{Clockwise above- Baleen by Paigefalk, Getty Images Signature; Humpback whale (baleen) by Craig Lambert, Getty Images; Orca whale (toothed) by Schmid-Reportagen, Pixabay}

There are 15 species of baleen whales compared to 77 species of toothed whales.  Baleen whales are generally larger, with the blue whale being the largest whale in our oceans.  Most baleen whales are migratory, moving between cold, polar waters that support large populations of prey and warmer waters that they use for breeding.  While warm water environments support less prey, they have fewer predators and other risks, allowing newborn youngsters to grow and learn to defend themselves before migrating back to richer feeding grounds.

Consider the Sei whale, one species of baleen whale from the Rorqual family that is known for their slender, pointed heads and fins.  They are one of the smallest baleen whales, growing to about 40′ in length as an adult.  Exact population numbers are not known, but it is estimated there are about 60,000 Sei whales worldwide.  Each Sei whale eats about one ton (2,000 pounds) of food each day, including krill, fish, and squid.  One ton holds close to a half million krill, a small crustacean weighing about 2 grams.  The entire population of Sei whales alone is consuming roughly 20 billion krill or other small fish each day!

Whales, hummingbirds, humans, frogs, and rabbits are all tetrapods, animals whose ancestors had legs.  Nearly all of the bones in one species can be found in each of the others, a condition called homology.  This is the result of divergent evolution where organisms from the same common ancestor evolve and accumulate differences, often resulting in an entirely new species. These differences are selected based on both biotic and abiotic factors in the habitat.  Whales have the same shoulder-arm-hand structure inside their side fins as a human arm.  While our hands and arms let us reach, grasp, and throw an object in the air, a whale’s fin delivers a powerful push through the water they live in.

^{Humpback pushing with fin by Yann-Hubert, Getty Images Pro; Human arm throwing a ball by South Agency, Getty Images Signature}

At the Jurica-Suchy Nature Museum, you can observe and learn more about homologous structure from our Sei whale / human arm skeleton comparison.  Plus we have more to show you concerning whales and other marine species from around the world.  Read more about whales on the following sites:

• NOAA Fisheries  (https://www.fisheries.noaa.gov/whales)
• WWF   (https://www.worldwildlife.org/species/whale)
• Whale & Dolphin Conservation, USA   (https://us.whales.org/whales-dolphins/facts-about-whales/)
• Center for Coastal Studies   (https://coastalstudies.org/)