Whale Morphology Glossary

- A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z -

asymmetrical coloring

Body coloring that doesn't match on both sides. Fin whales have dark gray to black coloration on their left sides (including baleen) and lighter colors on their right. Scientists think that the coloration may be a feeding adaptation. Usually, when fin whales feed, they lunge on their right sides (light side facing down). No one is sure how this might change prey behavior.




Long, hair-like plates in the mouths of toothless whales. Baleen is made of keratin and is used to filter prey like a strainer. The baleen plates are thin, hang from the top of the animal's mouth, and can number anywhere from 10 - 400+, depending on the kind of whale.


baleen whale

A type of whale that has baleen in its mouth rather than teeth. Baleen whales also have 2 blowholes and are generally larger than toothed whales. They tend to feed on smaller prey such as fish and copepods.



Crustaceans that attach themselves to some kinds of whales. A barnacle will often "hitch a ride" on the whale for a while so it can feed on plankton and other things in the water. Once the barnacle departs from the whale, it can leave scars. These scars look like white or black circles on humpback whales' skin. (Side note: in humpbacks, black skin scars white and white skin scars black)



Also known as a spout, a blow is the exhalation of air at the water's surface. A whale's blow looks like water, but it is actually air that condenses to form tiny water droplets just as human breath makes mist on a cold day. The whale's breath is warmer than the air, so it too forms a mist. Animals can be identified by the height and shape of their blow. Minke whales produce a very small blow, while blue whales can blow up to 30 feet. A whale can blow air out at speeds of over 300 miles per hour!



Whale nostrils. Toothed whales have one blowhole while baleen whales have two. The blowholes are used for breathing air just above ocean's surface. The whale only needs a second or two to expel air and take in another breath.



A thick layer of white fat used for protection from cold and as food reserves for long periods of not eating. The blubber in some whales such as the bowhead, can be as thick as two feet! Blubber insulates the whale in cold waters. It is located just under the skin.




Raised patches of rough skin on the faces of right whales, generally in the same places that humans have facial hair - above eyes, on the chin, and on the cheeks. Callosities are very similar to calluses that humans get on hands and feet when the skin there is rubbed frequently. All right whales have them, and their patterns along the bonnet (top of the head) and face are used by scientists for identification of individual whales. The callosities themselves are usually black, but they tend to be highlighted by light colored cyamids or whale lice that infest the skin.



A v-shaped, light colored marking on a whale. Fin whales usually have a chevron behind their blowholes. Minke whales sometimes have a light colored chevron on the backs of their heads.



Crustaceans that are the main food source for many baleen whales. These zooplankton species are very small in size (typically 1 - 2 mm in length) and provide food not only for whales but many other animals in the ocean. Some scientists believe that copepods produce the largest biomass on the planet!



Opposite coloration on the back (dorsal side) and belly (ventral side). A lot of whales have dark backs to camouflage them from above and light ventral sides to camouflage them from below.




Relating to the back.


dorsal fin

A fin located on an animal's back or dorsal side. It is used to help stabilize the whale.


dorsal ridge

A row of knuckle-like structures on the back of a whale in lieu of a dorsal fin. Gray whales do not have dorsal fins, but they do have a dorsal ridge.




An organ used for hearing. Whales have ears like other mammals, but the ears are not highly visible like human ears. In baleen whales, the ear canal is sealed shut by a wax plug to keep water out. You can tell the age of a whale based on the "rings" of the plug just as you can calculate a tree's age by counting its rings. Whales have 3 bones in their ears just like humans do - the malleus, the incus, and the stapes - but they have adapted to hearing under water instead of in air, so their hearing is different than ours.



An organ used for seeing. Whales have eyes that are adapted for seeing both under and above water. Sometimes whales poke their heads up above the water to take a look around. Scientists call this behavior a spy hop.




Sickle-shaped. Falcate describes the hooked shape of a dorsal fin. Fin whales have falcate dorsal fins.



Modified arms of a whale; also known as pectoral fins. In whales, flippers are used for steering.



A whale's tail. Whales have two, mirror-image shaped flukes. Flukes are often seen when a whale like a humpback dives down into the water. Humpback whales have patterns on the ventral (bottom) side of their flukes ranging from all white to all black. Each humpback fluke pattern is unique. These fluke markings are used by scientists to identify individual animals just as fingerprints can identify people.




A fiber-like protein produced by animals that forms such structures as hair, wool, hooves, claws, human fingernails, and whale baleen.



mammary glands

Glands that produce milk in female mammals. Mammary glands provide all of the nourishment that baby whales need for about the first year of their lives. Whale milk is extremely thick and fatty. It is about 3-4 times more concentrated than cow's milk and, depending on the kind of whale, can be up to 40% fat!


mammary slit

A small opening on a mother whale's lower abdomen that contains the mammary glands from which her calf feeds.


median notch

The indention or notch where a whale's two flukes meet



pectoral fins

Modified arms on the sides of a whale's body. Also called flippers, pectoral fins are used for steering the whale.



The stock of the tail located before the flukes. The peduncle is pumped up and down to propel the whale forward.




The word "rorqual" comes from a Norwegian word for "furrowed whale" and the Old Norse for "red whale" (perhaps because when feeding, the furrows have a pink tinge to them?) The furrows refer to the ventral folds running from the whale's mouth to its belly. There are several different species of whale that are considered rorquals, including the blue, fin, humpback, sei, Bryde's, and minke whales. All have ventral pleats, all are baleen whales, and all have a dorsal fin. They are also gulper feeders.



From the Latin word for "ship's beak," the rostrum is the platform-like top part of the whale's head or jaw. The rostrum is shaped like a huge beak.




Healed marks left after some kind of injury to the body. Whales can have scars from a number of sources: entanglements from fishing gear, boat and ship strikes, barnacles, and fights with or attacks by other animals (killer whales are known to attack other whales; giant squid can leave scars on sperm whales), to name a few.


sexual dimorphism

Physical differences between males and females of the same species. For example, most female baleen whales are larger than their male counterparts. In killer whales, the males have significantly larger dorsal fins than the females.


splash guard

The raised portion in front of the blowholes on some baleen whales. The splash guard is an adaptation that prevents water from going into the blowholes and lungs accidentally.



toothed whale

A whale that has teeth such as an orca, sperm whale, beluga, pilot whale, or dolphin. Toothed whales have only one blowhole and tend to go after larger prey than baleen whales. They use their teeth to catch or grab prey, not to chew.


tubercles or tubercules

Knobby protrusions on the rostrum of humpback whales. Each tubercle is about the size of a golf ball and contains a single, stiff whisker that is probably used for sensing in the water.




Relating to the abdomen or belly.


ventral pleats

Grooves on the throat and belly (ventral side) of some baleen whales. These pleats expand greatly when the whale feeds. As the whale opens its mouth, it sucks in many gallons of water and prey such as fish or copepods. The ventral pleats bulge out to accommodate the large amount of water. Then the whale closes its mouth and pushes the water out through the baleen, which traps the fish or copepods inside the mouth. The whale actually never swallows the salt water, only the food!



Something that still remains or contains a trace of the original structure, although it is no longer needed or used. For example, whales have small, vestigial hind limbs (leg bones) inside their bodies that are no longer needed for underwater survival.



whale lice (cyamids) Small crustaceans that live on right whales. These light colored animals eat dead skin from the whales' dark coloredcallosities and make the whale's callosity patterns stand out. This helps researchers identify right whales because callosity patterns are like human fingerprints - each one is different.

whale morphology

The study of the form and structure of whales.