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Order: Cetacea with apprx 80 spp.
Family name: Delphinidae (Ocean Dolphin)
Estimated population: 70,000 – 180,000
Life span: 50 years or more, females up to 80.

Killer whales, also called Orca, measure 27 – 33 feet, and have weight between 8000 and 13000 pounds.
They are the most widely distributed mammals in the world, and found in every ocean.
Killer whales are top predators, and the largest and fastest of the dolphins with top speed 50 km/h. They are the only dolphins that hunt one of their own cousins.

Both sexes generally remain within their natal matrilineal group.
Orcas have black body with white patches above the eyes, under the jaw and on the belly. The patches extend to their sides. Behind and below the dorsal fin is a grey “saddle patch”. The saddle - patch together with the shape of its dorsal fin is characteristic for each animal, and allow identification of each individual.

Hypothesis:
• Do killer whales have culture?
• What evidence is there for culture in killer whales?

Killer whales are one out of 4 spp where there has been done deep research according to culture (among Cetaceans).
When studies is performed based on wether they have culture or not, researches look for 3 different patterns of how culture is transmitted:

1. ‘Rapid – spread’: Complex form of behaviour spreading within one generation. Also called horizontal.
2. Mother – offspring: Complex form of behaviour transmitted between mother and offspring. Also called vertical.
3. Group – specific: Difference in complex form of behaviour between groups, which cannot be explained by genetic differences, shared environment, or sizes of groups. A combination of horizontal, vertical and oblique transmission.
   

Studying behaviour in killer whales is a hard task. Captivity of killer whales is both difficult and expensive, and in many cases they would not express natural behaviour. In wild they are just simply difficult to find!
Studies of wild animals provide data about vocal dialects, foraging pattern and greeting ceremonies. This is group – specific transmission of culture.
Evidence of learning in killer whales are based on how mother and other adult females instruct the offsprings in stranding techniques – a mother – offspring transmission of behaviour.

Killer whales live in highly stable social groups. The best known groups are those that live around Vancouver Island (and most likely their behaviour is typical for groups in other areas as well). Here you find 2 groups that can be distinguished by their diet, behaviour, social structure and genetics. The two groups are reffered to as ‘resident’ and ‘transient’.

" Residents" live in highly stable matrilinear ‘pods’ containing appx 12 animals. There are no known cases of animals changing pod! They feed on fish.
" Transients" live in smaller pods containing appx 3 animals. Individuals may leave their natal pod and travel temporarily with other transient groups. These are meat – eaters, feeding on seal, sea – lions, porpoises, and occasionally larger whales. Dorsal fin is pointier and saddle patch is slightly longer in transients.

Studies both at Vancouver Island and other areas show evidence for behavioural variations between groups, indicating group – specific transmission of culture.

Group – specific
Vocal dialects
The strongest evidence of culture in killer whales lies in vocal dialects of ‘resident’ pod observed at Vancouver Island.
Each pod has a set of 11 – 17 ‘discrete’ calls that are maintained even when pods are related. Some pods can share up to 10 calls, and pods sharing calls can be grouped in aucoustic ‘clans’. Call variations are a result of dialects being passed down through vocal learning, and therfor being modified over time.
Most likely aucoustic clans reflect commom matrilineal ancestry, and numbers of calls any two pods share reflect their relatedness. Other studies show that two close pods have modifications within their own calls, which do not result in divergence between the two pods.

These findings indicate that killer whales are capable of vocal learning, and that there is probably no genetic determination of dialects.
In 1988 Bowles followed vocal behaviour in a single captive killer whale. The calf was together with its mother, another adult female and a young male. The 2 females shared many call types, and there was no contact between the calf and its father. After a year the calf’s output was dominated by the one call which distinguished its mother’s reportoire from that of the other female, indicating selective learning. Genetic inheritance cannot be totally excluded in this case. Still the results point to a transmission mechanism, and that killer whale call dialects are culture – depending.

Foraging
Between pods variations are evident also in term of foraging. Some ‘transient’ pods are seen primarily during harbour seal pupping, while others are seen all year round.
There are strong indications that different ‘resident’ pods specialize on different salmon spp. The pods have various location accorded to abundance of prefered feed, and it’s suggested that accumulated knowledge of salmon distribution results in different behaviour.
It seems that different types of pods develop variable feeding techniques depending on location and feed. The adaptability allowing groups to take advantages of ‘non – normal’ food sources as well, eg discards of trawlers.

‘Resident’ predation on marine animals it extremely rare compared to ‘transient’, but observations recording the phenomena has revealed that all but one where from the same pod!

Greeting ceremonies
When ‘resident’ pods of one community meet they have ‘greeting ceremonies’
In one community two pods line up facing each other. They stop in formation for 10 – 30 seconds before approaching and mingling.
Some pods of another community engage in ‘beach – rubbing’. Pods within this community again show variability in preferred locations for rubbing.

Mother - offspring
Culture transmission between mother and offspring is clearly shown at shores in Crozet Islands and of Punta Norte I Argentina.
The killer whales swim ashore to capture pinnipeds, a profitable but risky method of feeding. These skills have to be aquired through learning, and not all individuals even within same group are able to perform this method.
Adult killer whales push their young up the beach and direct them against the prey – a clear encouragement. When juveniles become stuck on the beach, they are pushed back into water. Prey caught by adults is sometimes thrown towards the young, so they learn how to catch it themselves.
Adults are not limited to mothers. Other members of the group, both males and females, take part in the upbringing of the young. Bearing in mind that females live for years after birth of their last offspring, they provide a source of knowledge that is transmitted to other young.

Observations of 2 calves over a period of three years indicated how important the mother’s supervision was for the calf to learn the hunting technique.
The calves were aged 3 and 4 years old.
The youngest one was successfully catching prey at age 6. The mother was closely supervising the calf during beaching play: pushing it up the beach and pushing it back when stranded. She accompanyied the calf on unsuccessful hunting attempts, and assisted in the first successful capture by pushing it towards the prey and helping it to return to water after capture.
The calf aged 4 was not able to catch its own prey after 3 years. Its mother rarely took part in beaching play, and most likely did not hunt in this way. This calf was found permanently stranded by observeres , and would have died if not pushed out by people.
The behaviour of mother clearly enable the calf to learn the hunting technique more rapidly, and lack of instructions can be life – threatening!

Conclusion
The definition of culture is a way of communication between individuals that is aligned during lifetime, and fairly consistent over many generations.
According to this definition killer whales do have a strong cultural characteristic, which so far is described only for humans and chimpanzees.
The pods maintain their own group – specific culture even when exposed to a wide range of variations, and their dialects are highly stable - persisting for at least 6 generation. Their complex behaviour encompasses both vocal and physical behaviour. This distinctive, stable and sympatric vocal and behavioural culture is otherwise comparable only to humans.

Sources:
http://www.nwf.org/nationalwildlife/article.cfm?articleId=830&issueId=65

Luke Rendell and Hal Whitehead (2201) Culture in whales and dolphins. BEHAVIORAL AND BRAIN SCIENCES (2001) 24, 309–382, free article pdf

http://www.bbsonline.org/documents/a/00/00/04/91/bbs00000491-00/bbs.rendell.html
National Geographic Society: Document called “Wild side of Dolphins”
(I have the video – tape)

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