This list has been adapted and expanded from the Vancouver Aquarium Marine Mammal Research Programme
Baleen: The bristle-like plates that hang from a whale’s upper jaw bone and are used to filter prey (usually small schooling fish or shrimp-like crustaceans) from the water. Baleen whales include all of the large whales except killer whales and sperm whales, that have teeth more like those of dolphins.
Blow: a cloud or column of moist air forcefully expelled through the blowhole when the whale surfaces to breath. For some species of whale this can be seen from many kilometers away. It is also sometimes referred to as a spout- which gives the mistaken impression that it is predominantly expelled water.
Blowhole : the modified nostril located on the top of a whale or dolphins head. During dives the blowhole is sealed by a nasal plug which is retracted by fast-acting muscles upon surfacing for breathing. Baleen whales have two openings in their blowhole, while toothed whales have only one.
Bowride: When a whale or dolphin swims next to or in front of a vessel.
Breaching: a leap out of the water, exposing the majority of a whale or dolphin’s body.
Bubble netting: process in which whales either singly or cooperatively blow a circle of bubbles from under water in order to create a wall or curtain of bubbles that traps small schooling fish and makes them easier to capture in a single lunging gulp through the centre of the bubble curtain.
Calf: a young whale or dolphin, usually referring only to those born in the past year.
Cetacean: Whale, dolphin or porpoise; from the Latin word Cetus; marine mammal that lives entirely in the ocean.
Clan: Used predominantly to describe family groups of killer whales; pods within a clan have probably descended from a common ancestral group and therefore are probably more closely related to each other than to pods from other clans.
Copepods : tiny planktonic crustaceans, usually free swimming in the ocean.
Clicking: a series of close-spaced, broad spectrum sounds, mainly at very high frequencies, made by toothed cetaceans (all dolphins and killer whales) when echolocating. Each species of cetacean (whales, dolphins and porpoises) has distinct frequencies and patterns of clicks.
Competitive group: A term usually used for humpback whales, referring to a group of three or more males engaged in aggressive interactions.
Countershading: a coloring pattern found in many species of whales and dolphins, in which the dorsal (upper) surface is darker than the ventral (lower) surface so that whether viewed from above or below, the whale appears evenly coloured and inconspicuous.
Deep scattering layer: a layer of plankton and other small schooling fishes and sometimes squid that sinks to depths of more than 100m during the day and rises toward the surface at night. Several dolphin species specialize in feeding on fish and squid from the DSL.
Dolphin: Generally this term applies to a smaller cetacean with teeth (also known as an odontocete). Dolphins can have a pronounced rostrum (beak), or a blunt head, but always have cone-shaped teeth, which they use to grasp prey like fish or squid.
Dorsal fin: the fin along the midline of the back of most whales, dolphins and porpoises.
Echolocation: the process by which toothed cetaceans use vocalizations to obtain information about their surroundings; similar to SONAR, echolocation involves the production of rapid, high-frequency clicks that echo off objects in the whale's path.
Eye patch: the elliptically-shaped white patch located above and behind a killer whale's eye.
Flukes: the flat horizontal lobes that form the tail of all whale and dolphin species.
Fluking: when a whale or dolphin begins a deep dive, it lifts its tail into the air to help it thrust its body into a more steeply angled descent to deeper waters.
Foraging: feeding or searching for food.
Hydrophone: an underwater microphone used to listen to and record whale vocalizations
Juvenile: an immature whale or dolphin of either sex – usually smaller in size than a fully mature adult – but larger than a calf born in the past year.
Leapfrogging: a whale-watching practice involving the repeated placement of a boat directly in the whale's path; may contribute to more underwater noise and disturbance than other whale-watching techniques.
Krill: Tiny shrimp-like crustaceans that are eaten by whales, fish and birds, also known as Euphausiids;.
Lunge feeding: usually performed by baleen whales, who lunge with open mouths through dense concentrations of fish or crustaceans to feed.
Lobtailing: forcefully slapping the flukes against the surface of the water.
Matriarch: the eldest female in a matrilineal group, pod, or subpod of killer whales or sperm whales.
Matrilineal group: the basic social unit of resident killer whales, composed of a mature female and her immediate descendents; descendents may include mature males and mature daughters and their offspring.
Migration: regular journeys of animals between one region and another, usually associated with seasonal climatic changes or breeding and feeding cycles.
Mysticetes: This includes all the whale species that feed by filtering food through baleen plates rather than having teeth that they use to grasp prey.
Odontocetes: all whales and dolphins that have teeth rather than baleen; includes Sperm whales, Killer whales (Orca) and all dolphins and porpoises.
Pec-slapping: raising a flipper out of the water and slapping it noisily against the water's surface.
Pectoral fins: Although often referred to as fins – these are actually modified limbs with bone structures much like human’s arms and hands. They are used for stability and steering, and are more appropriately called flippers.
Penduncle-slapping/peduncle throw: also known as tail-breaching, throwing the rear portion of the body out of the water and slapping it sideways onto the surface, or on top of another whale.
Plankton: tiny, sometimes microscopic plants and animals that drift in the oceans forming the basis of the food chain.
Pleats/ Ventral Pleats: folds along throat and under the mouth of baleen whales that expand as they gulp in food and water prior to filtering or straining.
Pod: a group of usually related whales or dolphins of the same species that tend to travel together; in transient killer whales, the term "group" is used in preference to "pod" because groups are not necessarily made up of related animals.
Porpoise: Although this term is sometimes used to refer to any small dolphin, porpoises are distinguished from dolphins by always having blunt snouts/heads (no pronounced beak), and spade shaped teeth (dolphins have conical teeth).
Resting: whales and dolphins often group tightly together abreast, forming a line or cluster that dives and surfaces for air regularly as a cohesive unit. Because whales and dolphins are ‘voluntary breathers’ they need a certain level of alertness to continue swimming and surfacing to get air, and do not sleep the same way humans do.
Rostrum: The ‘snout’ or beak’ of a dolphin or whale.
Saddle: the grey pigmented area at the posterior base of the dorsal fin of some species of whales and dolphins (especially killer whales).
Skim feeding: Performed by some baleen whale species, like right whales, when they swim slowly through swarms of plankton at the surface with mouths part open, taking in water and prey (usually krill or copepods), which they then filter out through their baleen plates.
Socializing: A recognized behaviour category for whales and dolphins during which the majority of the group is predominantly engaged in aerial displays, body rubbing, and/or vocalizing as opposed to feeding, resting, or traveling.
Spyhop: a behaviour where a whale or dolphin raises its head vertically above the water, then slips back below the surface; a spyhop seems to be a means of obtaining a view above the surface.
Stranding: occurs when a live or dead whale or dolphin comes ashore and is unable to get back into the water.
Suction feeding: a method of feeding used by some whales and dolphins, by which they use their throat muscles and tongue in a piston-like action to suck prey into their mouths.
Tailstock: also called caudal peduncle, the tapered rear part of the body, from just behind the dorsal fin to just in front of the flukes.
Toothrake: The parallel rake-like scars that can be left on a whale or dolphin’s body, dorsal fin, or tail flukes after being bitten by another (toothed) whale or dolphin.
Travelling: a recognized behavior category for whale sand dolphins, during which the majority of the group is swimming forward consistently in one direction at a moderate to fast pace, usually in a tight formation.
Whale: This term is used to refer to any large cetacean, but technically scientists distinguish between toothed cetaceans (odontocetes) and those with baleen plates instead of teeth (mysticetes). Killer whales and sperm whales are odontocetes, while blue whales and humpback whales are mysticetes.