Behaviors of "Kodiak Killers" and Stellar Sea Lions


Transient killer whales are different from resident KWs (orcas). Males have the very tall dorsal fin, up to 6 feet tall. Mike and Winston, our ACS volunteers, explain: "Resident Orcas feed on fish--but NOT on marine mammals. Transient orcas feed on marine mammals. How do you tell the difference? Look at the top of the DORSAL fin. If it is rounded, the orca is a resident. If it is pointed, the orca is a transient." Which type of orca do you see in this photo sent by Mike?

Lori Mazzuca is a Research Fisheries Biologist working with government agencies (NOAA-NMFS-AFSC-NMML) in Kodiak, Alaska. She saw a pod of killer whales ("Kodiak Killers") appear in the harbor on March 22. The killer whales (Orcas) remained in the bay outside of the city harbor entrance for about 3 hours. Lori said, "I observed an attack on at least one Steller's sea lion (maybe as many as 3 at once), but I did not observe a kill (or "supper")." Lori saw some interesting predation behaviors. She wrote a timeline to share events with you. As you read the timeline, list behaviors of the two species involved: killer whales (KWs) and Steller?s sea lions (SSLs).

Timeline of Events: March 22, 2003, Kodiak, Alaska
2:30 pm. Transient KWs ("Kodiak Killers") passed by my house headed toward town and the harbor. During a snowstorm (and 20 degrees!), I looked out my living room window and saw the "Kodiak Killers" pass by. I followed them along the waterfront in the channel down to the breakwater by the processing plants. Two colleagues were unable to come and help, so it was just me out in the cold, along with a few townfolk watching the "show." The killer whales obviously had all of the SSLs around the area on "high alert," as the SSLs huddled together in groups and remained vigilant throughout the day.

3:30 pm. Arrived at the breakwater/harbor entrance in town.

3:30 pm until 6:00 pm. KWs calmly cruised around the area--only once with a spurt of "play" exhibited by a few porpoisings by calves.

6:00 pm until 6:05 pm. Sudden porpoising by the adult male KW immediately followed by the 2 adult female KWs doing the same. About 8-10 porpoisings observed by the adult KWs. A few SSL flippers and bodies were seen on occasion in the midst or "running" from the KWs. SSLs were also seen flying through the air as a result of a whale-hit.

6:05 pm until 6:30 pm. Strangest thing: After the above, it appeared a SSL was injured and floating at the surface, unable to swim or dive. I say "injured" because I saw its flipper moving as if in an effort to dive or swim. But despite the effort, its body floated at the surface for the duration. (My feeling from watching for half hour--with no direct evidence --was that its back may have been broken.) Two other SSLs were with the injured animal. They remained tight to it and never to leaving it, while often looking up at the KWs. The KWs left the SSLs immediately after the injured SSL remained floating at the surface and "flailing" its flippers. The KWs swam to a "post" and remained there--40-50 meters away from the floating SSL and its two companions. There, the KWs lined up like a chorus line, with their heads pointed directly at the floating SSL and its two companions. The KW's remained there for about 25 minutes, logging at the surface and intermittently spy-hopping to look at the SSLs. The female KWs logged and did all of the spy-hopping (about 5 "sets" of spy-hops) while the male KW always logged and never spy-hopped. All KWs remained in their original positions, with the male KW always to the right of the group. When not in line with the group, the calves remained behind the adults (adults between the sea lions and calves). The calves swam and surfaced behind the adults, but never in front of them.

6:30 pm. KWs dove together and appeared by the dive to head in a direction the left and away from the SSLs.

6:50 pm. KWs surfaced beyond the SSLs and far to the left. Immediately after this surfacing, the floating SSL with flailing flippers and two SSL companions moved in the direction of the processing plants-- where the KWs had been in a line watching them. When they got closer to where I was watching, I saw that the two uninjured SSLs were "helping" to bring the injured SSL to the pilings beneath the processing plants, right to the area where 25 other male SSLs were huddled to watchthroughout the ordeal. (This is also where I was standing). The two uninjured animals appeared to "help" by alternately swimming beneath the injured animal and "lifting" it as they swam. It appeared the 2 uninjured SSLs were doing some kind of "figure 8" swim under and beside the injured SSL in a fairly well choreographed manner to keep the injured animal moving forward, toward the processing plant. When all three SSLs were about 15 meters from the pilings, the two uninjured animals pushed the injured animal underwater and all three went underneath the logs against the pilings (and on the surface) so as to get beneath the processing plants and to the pilings. (For safety?) I never saw any blood. I did not get a close-up look at the injured animal because the other two pushed it below and then under our platform.

7:05 pm. It was freezing cold, getting dark, and I headed home. I never saw the KWs resurface.

7:30pm. Thanks to a call from an incoming fishing captain, I learned the KWs had indeed left the "attack" area and were on their way out of town the way they came--by my house. I looked out the window and there they went...perfect left sides, darkness falling, and of course, me with no camera in hand!

Try This!
  • What behaviors did you list for the killer whales? The SSLs? In what ways could it be said that each helped members of its own species?
  • Find in the text where Lori says she saw "useless left sides." Read Lori?s quote that follows, and then explain in your own words what she meant: "To date, researchers doing long-term studies of killer whales in the Puget Sound have catalogued killer whale identification shots of their "left sides" (includes the dorsal fin and saddle patch). Of course right and left side saddle patches and fins are not the same--just like the right/left sides of our faces aren't exactly the same. I think someone started it that way (rather than right sides) and it stuck."
  • Lori and some colleagues are going to the Unimak/False Pass area during May/June when the gray whale migration north is underway. "From past data," explains Lori, "we concluded that mid-May through about the first week in June is a peak time for cow/calf pairs to be coming through. Last season we came across a group of transient killer whales feeding on a gray whale, so we are going back again to look for transient killer whales." If you were going with Lori, what would you expect to see? What would you want to find out?