Remote-Url: https://www.orcanetwork.org/nathist/transients.html Retrieved-at: 2021-09-16 18:00:32.067082+00:00 ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓ ┃ ┃ ┃ Transient orcas ┃ ┃ Also known as Bigg's Killer Whales _CJZ2372 ┃ ┃ ┃ ┃ Photo of T14 (Pender "O4") by Chris Zylstra, April 27 2008, near Hein Bank. ┃ ┃ ┃ ┃ Photo-identification Catalogue of Bigg’s (Transient) Killer Whales From Coastal ┃ ┃ Waters of British Columbia, Northern Washington, and Southeastern Alaska. ┃ ┃ ┃ ┃ Dalheim, Marilyn, Paula A. White (2010). Ecological aspects of transient killer ┃ ┃ whales (Orcinus orca) as predators in southeastern Alaska. Wildlife Biology, ┃ ┃ Volume 6, No. 3: 308-322. ┃ ┃ ┃ ┃ Barrett-Lennard, Lance G., Craig O. Matkin, John W. Durban, 5, Eva L. Saulitis, ┃ ┃ David Ellifrit (2011). Predation on gray whales and prolonged feeding on ┃ ┃ submerged carcasses by transient killer whales at Unimak Island, Alaska. Mar ┃ ┃ Ecol Prog Ser, Vol. 421: 229-241. ┃ ┃ ┃ ┃ Any attempt to describe transients, or for that matter any community of orcas, ┃ ┃ presents a challenge because the best way to understand them is by comparison ┃ ┃ with other orca communities. It's the old conundrum: "Where's the rake?" It's ┃ ┃ by the hoe. "Where's the hoe?" It's by the rake. Orcas worldwide live as ┃ ┃ members of ancient sophisticated societies. Each orca community behaves ┃ ┃ according to traditions and rules that, in their complexity and variability, ┃ ┃ have no parallel except in human societies (Rendell and Whitehead 2001). ┃ ┃ ┃ ┃ Transient orcas provide a good illustration of orca cultures. In the ┃ ┃ mid-1970's, Dr. Mike Bigg, the pioneer field researcher on the orcas of British ┃ ┃ Columbia and Washington State was commissioned by the Canadian Dept. of ┃ ┃ Fisheries and Oceans to survey the whales to determine how many animals there ┃ ┃ were. Canada wanted to know whether the whale population could sustain the ┃ ┃ removal of 10 to 15 animals per year for the marine park industry. Bigg's work ┃ ┃ showed that the overall population was very small and could not endure such ┃ ┃ losses, but he discovered much more than just their numbers. He began to notice ┃ ┃ that in addition to the "normal" orcas (residents) that travel in large pods, ┃ ┃ there were occasional small groups transiting through, usually only 3 or 4 to a ┃ ┃ group, traveling erratically close to the rocky shores. He assumed these ┃ ┃ animals had been rejected by their pods, like the nomadic lions of the ┃ ┃ Serengeti. So Bigg called them transients. ┃ ┃ ┃ ┃ As the first person to systematically observe these whales, Bigg could not have ┃ ┃ known that the Pacific Northwest is blessed to provide habitat to two ┃ ┃ drastically different forms of killer whales, now recognized as living in ┃ ┃ separate and distinct cultures. In the thirty-plus years since Bigg began orca ┃ ┃ studies, no migration by either sex from either type into the other has been ┃ ┃ recorded. Membership in each begins at birth and cultural bonds and identity ┃ ┃ continue throughout life. Residents and transients differ in diet, vocal ┃ ┃ traditions, habitat range, morphology (shape of dorsal fin, etc.), pigmentation ┃ ┃ patterns (such as the eye patch) and genetically. Though they cross paths ┃ ┃ routinely throughout the inland waters of BC and Washington State, the two ┃ ┃ forms are becoming, or by some accounts are already, separate species. DNA work ┃ ┃ indicates that they have not interbred for at minimum one hundred thousand ┃ ┃ years. Each orca population worldwide seems to follow its own rules to guide ┃ ┃ their diets, associations patters, behaviors and vocalizations, rather than ┃ ┃ simply show similarities with either residents or transients. Some researchers ┃ ┃ have suggested that residents should really be called "fish-eaters" and ┃ ┃ transients "mammal-eaters." ┃ ┃ ┃ ┃ ┃ ┃ _CJZ2438 ┃ ┃ Photo by Chris Zylstra ┃ ┃ ┃ ┃ Transient killer whale pods are generally comprised of an adult female and two ┃ ┃ or three of her offspring. Among the differences between residents and ┃ ┃ transients are that while resident orcas of both sexes stay within shouting ┃ ┃ distance of their mothers their entire lives, only first-born male transients ┃ ┃ maintain such intense fidelity to their mothers. Optimum pod size for ┃ ┃ transients is three, so whenever a third offspring is born, one of the siblings ┃ ┃ often leaves. The rule seems to be that the eldest son can stay, but all but ┃ ┃ one of the others may have to go. ┃ ┃ ┃ ┃ After departing their mother's company, roving males may join up with other ┃ ┃ groups from time to time. Females are more likely to join up with other ┃ ┃ transients, at least for a time. It isn't known if the hosts are relatives. ┃ ┃ Departing offspring, whether male or female, tend to leave their mother at 5 to ┃ ┃ 12 years of age. ┃ ┃ ┃ ┃ Orcas have no predators and are capable of ingesting virtually any bite-sized ┃ ┃ living thing found in the ocean, but residents select only fish (mainly Chinook ┃ ┃ salmon) and squid to dine upon, while transients never touch a fish or squid, ┃ ┃ but prey exclusively on seals, sea lions, porpoises, dolphins, and other large ┃ ┃ whales. Orcas everywhere appear to specialize on certain prey. This way they ┃ ┃ divide up the available food in the marine ecosystem and avoid competition. ┃ ┃ Salmon, resident orcas' preferred delicacy, are widely dispersed, so residents ┃ ┃ are able to travel in large groups across wide expanses. Transients tend to ┃ ┃ move in their small groups silently, usually around seal haulouts. They ┃ ┃ silently stalk and outwit their wary food, zig-zaging in unpredictable ┃ ┃ patterns. The optimum number of orcas in a hunting party is three, since three ┃ ┃ can most easily detect and surround mammalian prey. ┃ ┃ ┃ ┃ In one transient family, the second-born male offspring (M3) left his mom (M2) ┃ ┃ at about age 7 when a third offspring (M4), a female, was born. When M4 was ┃ ┃ about 10 another sibling (M5) was born, and two years later M4 departed, ┃ ┃ keeping pod size at three. M4 was photographed with another group of transients ┃ ┃ thousands of miles away, but two years later, after her oldest male sibling ┃ ┃ (M1) died, she returned to her mother's side, once again bringing pod size back ┃ ┃ to the prescribed number of three. At least two male transients are usually ┃ ┃ seen alone, but as yet no solo females have been found. ┃ ┃ ┃ ┃ Residents often seem to celebrate festive occasions and gatherings of pods with ┃ ┃ repeated breaches, taillobs, cartwheels and spyhops, accompanied by a wide ┃ ┃ variety of vocalizations. Transients wait until their prey have been subdued ┃ ┃ before they make themselves known. Occasionally transients may gather in group ┃ ┃ of a dozen or more and can also be quite acrobatic during socializing sessions. ┃ ┃ Seals and porpoises may be tossed around like a frisbee, batted into the air ┃ ┃ with powerful tail slaps, or held underwater until drowned. Orcas probably got ┃ ┃ their exaggerated reputation as killer whales from reports of transients ┃ ┃ viciously ripping marine mammals, including large whales, to shreds. To date, ┃ ┃ however there are no known cases of orcas eating or even harming a human. ┃ ┃ ┃ ┃ About 320 individually identified transient orcas are commonly seen along the ┃ ┃ coastline of Washington and British Columbia and from Southeast Alaska to ┃ ┃ California. Gulf of Alaska transients also number just over 300, and a third ┃ ┃ clan was all but wiped out by the 1989 Exxon Valdez oil spill. Fewer than ten ┃ ┃ survivors remain in 2009, none of which are reproductive females. These ┃ ┃ transient communities haven't all been photographed, however, and new adult ┃ ┃ individuals in the two larger groups are still occasionally documented. ┃ ┃ ┃ ┃ References ┃ ┃ ┃ ┃ Baird, R.W. and H. Whitehead. 2000. Social organization of mammal-eating killer ┃ ┃ whales: group stability and dispersal patterns. Can. J. Zool. 78: 2096-2105 ┃ ┃ ┃ ┃ Baird, R.W. 2000. The killer whale-foraging specializations and group hunting. ┃ ┃ In: Cetacean societies: field studies of dolphins and whales. Edited by J. ┃ ┃ Mann, R.C. Connor, P.L. Tyack, and H. Whitehead. University of Chicago Press, ┃ ┃ Chicago. pp. 127-153. ┃ ┃ ┃ ┃ Baird, R.W., and Dill, L.M. 1995. Occurrence and behaviour of transient killer ┃ ┃ whales: seasonal and pod-specific variability, foraging behaviour, and prey ┃ ┃ handling. Can. J. Zool. 73: 1300- 1311. ┃ ┃ ┃ ┃ Bigg, M.A., Ellis, G.M., Ford, J.K.B., and Balcomb, K.C. 1987. Killer whales-a ┃ ┃ study of their identification, genealogy and natural history in British ┃ ┃ Columbia and Washington State. Phantom Press, Nanaimo, B.C. ┃ ┃ ┃ ┃ Dalheim, Marilyn, Paula A. White (2010). Ecological aspects of transient killer ┃ ┃ whales (Orcinus orca) as predators in southeastern Alaska. Wildlife Biology, ┃ ┃ Volume 6, No. 3: 308-322. ┃ ┃ ┃ ┃ Rendell, Luke & Whitehead, Hal. 2001. Culture in whales and dolphins. Behav. ┃ ┃ Brain. Sci. v24(2): 309-382 ┃ ┃ ┃ ┃ ### ┃ ┃ ┃ ┃ Home ┃ ┃ ┃ ┃ Search ┃ ┃ ┃ ┃ Top ┃ ┃ ┃ ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛ ©Orca Network Please contact Orca Network to inquire about educational use of any materials on this site.