Whales are divided into two fundamental groups, leading to two distinct answers regarding what their “teeth” are called. One group possesses true teeth, while the other has a unique structure that serves as a replacement. This anatomical difference is the single most defining physical characteristic separating these two major groups of marine mammals.
Toothed Whales and Their Dental Structure
Toothed whales have a remarkably uniform dentition, meaning all the teeth look similar. These teeth are typically cone-shaped, designed primarily for seizing and holding slippery prey rather than for grinding or chewing food. Unlike most other mammals, toothed whales develop only a single set of teeth that must last their entire lives. The number and location of these teeth vary widely across different species. Some dolphins can have over 160 teeth, while species like the sperm whale only develop teeth in their lower jaw. The male narwhal’s prominent tusk is a specialized example, being a single, elongated upper left canine tooth.
Baleen: The Unique Filtering Plates
The other group of whales possesses a structure called baleen instead of teeth. Baleen is a filtering apparatus made of keratin, the same fibrous protein found in human hair and fingernails. This material forms hundreds of parallel plates that hang down from the upper jaw, arranged like vertical blinds inside the mouth. Each baleen plate is thin and triangular, with a thick base embedded in the gum line and a frayed, hairy fringe along the inner edge. The inner fringe of soft bristles interlocks to form a dense, sieve-like mat that allows water to pass through while trapping food particles.
How Teeth and Baleen Determine Diet
The presence of teeth or baleen dictates the whale’s lifestyle, particularly its hunting methods and diet. Toothed whales are active predators that rely on echolocation to detect, track, and capture large, mobile prey. Their conical teeth grasp and secure food like fish, squid, and other marine mammals, which are typically swallowed whole without chewing. Baleen whales are filter feeders, consuming vast quantities of tiny organisms rather than individual large prey. They use their baleen plates to strain small schooling organisms such as krill, copepods, and small fish from the water column.