Suddenly out of the deep blue water appears a whale shark directly beneath me. The gentle giant moved gracefully to the surface of the water and began feeding next to me. I had been snorkeling off the coast of Tofo in Mozambique and felt that this was a dream come true. Experiences like this make me appreciate the variety of nature’s feeding techniques. You see whale sharks and baleen whales are both filter feeders, animals that eat by straining tiny food, like plankton, from the water. But how they go about filter feeding is completely different.
In whale sharks, teeth don’t play a major role in feeding. In one of their filter-feeding methods, they suction water into their mouths at high velocities while remaining stationary. Food moves through filtering pads that cover the entrance of their throats. The filtering pads are broad mess pads full of millimeter-wide pores that act like a sieve, allowing water to pass through while capturing food particles.
Baleen whales feed in an entirely different way. There are 12 baleen whale species divided into 4 families, each of which has a slightly different feeding method. Baleen whales were named for the long plates of baleen that hang in a row (similar to the teeth of a comb) from their upper gumline. Baleen plates are flexible, strong, and made of a protein similar to our fingernails. These plates are broad at the whale’s gumline and taper into a fringe that forms a curtain inside the whale’s mouth. Generally, baleen whales strain large volumes of ocean water through their baleen plates, trapping the food on their baleen. Their food (tons of krill, other zooplankton, crustaceans, and small fish) are licked off their baleen using their tongue and swallowed.
Gray whales, a family of baleen whales, are bottom feeders. They suck sediment and small benthic crustaceans called amphipods from the sea floor. To do this, they slowly swim on their sides and filter their food through their baleen plates. By feeding this way, they often leave long trails of mud behind them, and “feeding pits” in the sea floor.
Like other baleen whales, right whales filter their food through their baleen plates, but they do it in a different way. They’re skimmers. Along the surface of the water, right whales swim with their mouth open, so food is caught in the baleen fringes inside their mouth. Check out the video below where a right whale narrowly misses eating a piece of plastic.
Whale sharks and baleen whales are both filter feeders, but when you look at the details of how they feed, you realize how different they are. Understanding animal behavior such as feeding means we can better protect them from our human activities and live together in harmony.