Hunting Behavior in type a and type b Orcas

Biology 342 Fall 2014

IMITATION: LEARNING FROM SKILLED ADULTS

Fig 1. Type B Orca's approach an ice floe with a seal laid out on it. Note a calf, third from the left, and another possible calf on the far right.

Wave-washing behavior in Type B killer whales is developed through imitation. If calves are present in a pod that is spy-hopping in order to find a seal to target, the calf will spy-hop alongside it’s mother (Pitman & Durban, 2012).

Self-stranding technique in Type A killer whales is developed through social play and imitation. During beaching-play there may or may not be seals present. Young calves associate with an adult female or other young orcas. Often calves will associate with their mothers when self stranding, however, calves whose mothers self strand significantly less than the other females in the pod will associate with other pod females (Guinet, 1991). The implication is that allopaternal teaching “could be related to the the related to the alloparent’s experience or skills” is unprecedented in studies of other species (Guinet, 1991). Associating with an adult female not only facilitates mimicry, but also increases the chance of survival in this risky behavior. Calves may require the help of an adult to get off the beach; when the young orcas become stuck their mothers push the calves back to shore and also “have been observed creating waves to lift the calves off the shore” (Guinet, 1991).

Type A killer whales have extremely low reproductive rates, which may facilitate the long apprenticeship of calves learning to self-strand. 6- to 7-year old orcas have been still associated with their mother, while in the North Pacific calves don’t associate closely beyond 3 years of age (Guinet, 1991). While this may be associated with the skills that the calves must attain, it may also be that “hunting of large marine mammals may require more experience and strength than capturing a fish.” (Guinet, 1991) By 6 years old a calf may be able to capture its first seal using self-stranding, but it will still require the help of an adult to get back to the water. For comparison, resident killer whales will capture their first fish within their first year of life and will be weaned by 22-24 months (Guinet, 1991).