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Killer Whales Orcinus Orca

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Introduction

Killer whales, Orcinus orca, are mammals, that are part of the Cetacea order, the Odontoceti suborder and the Delphinidae family (Ketten, 1997). They evolved from land creatures, requiring a multitude of adaptations so that the transition to water was successful. They live in all oceans, but are most commonly found in cool, temperate waters (Strager, 1994).
Communication between killer whales is primarily used for reproduction, orientation and hunting (Erbe, 2002; Holt et al, 2009). The three sounds that killer whales produce are echolocation clicks, whistles and pulsed calls (Deecke et al, 2005). Clicks occur in a series and are short sounds used for orientation and when finding prey; whistles are used for communication when …show more content…

In addition, many pods of whales, both resident and transient ones around the world, have a distinct repertoire of calls; certain pods that have similarity in these calls are grouped together as clans (Ford, 1991). When pods within clans share most of the same calls, but also have a few different one, the pods are said to have different dialects and are referred to as subclans (Ford, 1991). These repertoires are suspected to be specific to the matrilineal line, but are thought to be learned behaviours rather than genetically inherited (Ford, 1991). This is due to the fact that even when pods from different clans travel together, their communication remains independent (Ford, 1991). The types of calls vary with the type of activity that the whale undergoes, as well as the social setting (Ford, 1989). In British Columbia, studies have shown that whale pods have 7-17 discrete call types, whereas in Alaska there were 3-16 discrete call types (Ford, 1991; Strager, 1994). In one study on Alaskan killer whales, six of the nine pods studied exhibited unique repertories, indicating that killer whales were capable of having vocal traditions (Strager, 1994). These calls may also be unique due to geography differences, as calls recorded in different parts of the world showed overlap; either meaning that these calls were formed independently, there are certain calls …show more content…

This partly because the frequency ranges of boats and whales can overlap (Holt et al, 2009). If whale individuals are unable to communicate with other members of their pod, there would be less cohesion when hunting, difficulty in finding a mate, and an overall an increase in stress (Holt et al, 2009). There have also been cases where boat motors have impaired the whales to even detect their prey (Barrett-Lennard et al, 1996). These anthropogenic, background sounds are thought to interfere with communication between individuals by masking the whale's calls, particularly if at specific threshold level (Foote et al, 2004). Ways that whales have been shown to adapt include changing the amplitude and duration of calls (Foote et al, 2004; Holt et al, 2009). As the background sounds increased by one decibel, the amplitude also increased by one

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