Balaenoptera – Rorquals

Rorquals represent the largest group within the baleen whale family, distinguished by their unique feeding mechanism and impressive physical characteristics. These marine mammals are characterized by a series of distinctive ventral grooves running from their chin down to their navel. These grooves are more than just a physical characteristic; they are a critical adaptation that facilitates their unique feeding strategy known as “gulp feeding.” This method allows rorquals to take in a massive volume of water and prey, then expelled through their baleen plates, trapping food inside the mouth.

Among the members of the Balaenoptera genus is the blue whale (Balaenoptera musculus), the largest animal known to have ever existed on Earth, living or extinct. This monumental creature can reach lengths of up to 100 feet (30 meters) and weigh as much as 200 tons (181 metric tonnes), yet it feeds primarily on some of the smallest organisms in the ocean.

The diet of rorquals is predominantly composed of small, shrimp-like animals known as krill, particularly in the case of the blue whale. Other species within this genus may also consume small fish and various types of zooplankton and phytoplankton. Despite their gargantuan size, rorquals rely on these tiny organisms for sustenance, consuming thousands of pounds of food each day during feeding seasons to support their massive energy requirements.

The feeding process of rorquals is a marvel of biological engineering. Upon locating a dense swarm of prey, a rorqual will accelerate into the midst of it and open its mouth widely. The ventral grooves expand, allowing the mouth cavity to inflate dramatically and take in a large volume of water and prey. The mouth then closes, and the whale uses its powerful tongue to push the water out through the baleen plates, leaving behind the trapped food to be swallowed.