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beach rubbing
is a behaviour common to the northern resident whales. It is most often observed at a series of small beaches within the Robson Bight (Michael Bigg) Ecological Reserve where the whales rub their bodies on the small, smooth pebbles, sometimes for several hours.See the Beach rubbing video for more. |
 photo by L.Barrett-Lennard |
| blowhole nostril located on the top of the head. During dives the blowhole is sealed by a nasal plug which is retracted by fast-acting muscles upon surfacing for breathing. |
 photo by J.K. Ford |
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breach |
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| clan one or more pods that share a related dialect; 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. |
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clicking a series of close-spaced, broad spectrum sounds, mainly at very high frequencies, made when echolocating. Each species of cetacean (whales, dolphins and porpoises) has distinct frequencies and patterns of clicks. |
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| community comprises all pods that travel together; pods from different communities have never been seen together. |
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| countershading protective coloring 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. |
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| dialect a unique set of discrete calls made by an individual whale and fellow pod members; dialects of most resident pods can be distinguished either by ear or with a sound analyzer. |
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| discrete call a type of communication vocalization that sounds the same each time it is produced; on average, resident pods produce about twelve different types of discrete calls. |
 Sample of a discreet call from A-clan |
| dorsal the fin along the midline of the back of most whales, dolphins and porpoises. |
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| echolocation the process by which killer whales and other toothed cetaceans use vocalizations to obtain information about their surroundings; similar to SONAR, echolation involves the production of rapid, high-frequency clicks that echo off objects in the whale's path. |
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| eye patch the elliptically-shaped white patch located above and behind a killer whale's eye. |
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| flukes the horizontal projections forming the tail of the whale. |
 photo by J.K. Ford |
| foraging is the most common activity of resident killer whales. Whales are foraging when they are feeding or appear to be searching for food. |
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| 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. |
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| haul-out a rocky reef or beach where seals or sea lions climb out of the water to rest. |
 photo by L.Barrett-Lennard |
| hydrophone an underwater microphone used to listen to and record whale vocalizations. |
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| juvenile an immature whale of either sex. |
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| keel distinctive bulge on tail stock near flukes, can be on upper side, underside or both. |
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leapfrogging |
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| lobtailing making a loud splash by forcefully slapping the flukes against the surface of the water. |
 photo by J.K. Ford |
| maternal genealogy a family tree showing the ancestry of an individual through it's mothers relatives; also known as a matriline. See this example of the A-clan. |
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| matriarch the eldest female in a matrilineal group, pod, or subpod. |
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| 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. See this example of the A-clan. |
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| migration regular journeys of animals between one region and another, usually associated with seasonal climatic changes or breeding and feeding cycles. |
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| offshore killer
whales a little-known population of killer whales, found mostly in offshore waters off British Columbia but also identified in California, Washington, and southeastern Alaska; more closely related genetically to residents than to transients; appear to travel in generally larger groups than residents or transients. |
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| pec-slapping raising a pectoral fin out of the water and slapping it noisily against the water's surface. |
 photo by J.K. Ford |
pectoral fins paired, paddle-shaped forelimbs used for stability and steering, also called flippers. |
 photo by L. Barrett-Lennard |
| penduncle-slapping 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. |
 photo by L. Barrett-Lennard |
| pod in resident killer whales, a group of maternally related individuals 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. |
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| resident killer
whales a form of killer whales that feeds preferentially on fish, especially salmon, and has a very stable social structure. |
 photo by J.K. Ford |
| resting whales often group tightly together abreast, forming a line that dives and surfaces for air regularly as a cohesive unit; whales version of sleep. |
 photo by J.K. Ford |
| saddle the grey pigmented area at the posterior base of the dorsal fin. |
 Saddle patch |
| socializing behaviour includes various aerial displays participated in by all the whales in a group or only a few while the others may rest or forage. These activities are most often observed in juvenile whales and appear to be a form of playtime. |
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| spout or blow a cloud or column of moist air forcefully expelled through the blowhole when the whale surfaces to breath. |
 photo by J.K. Ford |
| sprouter an adolescent male whose fin is undergoing a rapid spurt of growth, this usually takes place around 15 years of age. |
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| spyhop a behaviour where a whale 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. |
 photo by J.K.Ford |
| stranding the coming to land, either dead or alive of a cetacean. |
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| 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. |
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| transient killer whales a form of killer whales that feeds preferentially on marine mammals and has a looser social structure than that of residents; transients also differ from residents in dorsal fin shape, group size, behaviour, vocalizations and genetics. |
 photo by L.Barrett-Lennard |
| travelling swimming forward consistently in one direction at a moderate to fast pace, usually in a tight formation. |
 photo by J.K.Ford |
| whale encounter an occasion when one or more identifiable individuals have been located. |
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