Pam J. Stacey and Robin W. Baird
Marine Mammal Science 13:504-508. 1998.
No Abstract is available. The entire text of the Note is below.
Observations of cetacean births are rare, as are reports of the behavior of the mother and other group members immediately after a birth. Scientists have observed births of at least five species in the wild: the killer whale (Orcinus orca), sperm whale (Physeter macrocephalus), beluga (Delphinapterus leucas), false killer whale (Pseudorca crassidens), and gray whale (Eschrichtius robustus) (Balcomb 1974, Leatherwood and Beach 1975, Mills and Mills 1979, Jacobsen 1981, Weilgart and Whitehead 1986, Béland et al. 1990, Notarbartolo di Sciara et al. 1997). There have also been a few published accounts of cetacean births in captivity (e.g. Asper et al. 1988). This note describes the birth of a wild killer whale in a well-documented "resident" pod and the unusual behavior of the group.
Our observations were made on 11 July 1990 in Juan de Fuca Strait, just south of Victoria, British Columbia (48 degrees, 22.5'N, 123 degrees, 22.5'W). The killer whales observed were part of the "resident" group designated as L-pod (Bigg et al. 1987). The whales were located at approximately 1600 hrs (local time), and followed for 2.5 hours. Observations were made consecutively from two different vessels, a 7-m Zodiac and a 4.7-m Zodiac, at distances usually ranging from 5 to 30 m. Ad hoc behavioral observations were voice-recorded onto a microcassette recorder.
The group initially contained about 11-13 whales. Seven whales were identified from photographs (over 130 black and white photographs were taken) by comparing them with a published catalogue (Bigg et al. 1987, see also Ford et al. 1994) and an unpublished catalogue maintained at the Center for Whale Research (Friday Harbor, Washington, U.S.A). Whale gender, age and maternal relatedness were also determined from these catalogues. Some whales left the group before photographs were taken, although one of these whales was identified visually. The mother (L55) of the infant was 13 years old at the time (Bigg et al. 1987). The other whales identified were L4 (L55's mother, estimated at 41 years of age), L61 (a 17 year-old male and L55's probable brother), L27 (a 25 year-old female), and L27's three offspring (L62, a 10 year-old male; L68, a five year-old male, and L80, a young-of-the-year of unknown gender). Based on association patterns, L27 is probably closely related to L4 and her offspring (Bigg et al. 1990). All of these whales belong to the L8 subpod (Bigg et al. 1987). L38, a 25 year-old male in the L10 subpod, was identified visually. Prior to this day, L8 and L10 subpods were last seen by researchers on July 3, 1990. L55 was not accompanied by a calf at that time (D. Ellifrit, Center for Whale Research, personal communication).
Upon contact, we noted that both the whales' behavior and direction of travel were unusual for "resident" killer whales in this area. The whales were first seen travelling single file at about 10 knots towards the southeast. After about five minutes of repeated surfacing with no long dives, the whales suddenly turned and retraced their route to where we had first encountered them. Milling ensued for about 2 minutes in a 20-m2 area, with occasional high-speed movements and splashing. Several times over a period of about 30 seconds one whale rotated quickly at the surface. About 5 seconds after the last rotation, three whales spyhopped with a neonate jointly held on their rostrums. The neonate remained motionless while held about 1 m above the surface for 2-3 seconds. The group then swam clockwise in circles about 50 m in diameter. The neonate was re-sighted about 10 minutes later, swimming between two adult females, L55 and L27, who were circling with the rest of the group about 1 m apart. We probably did not see the neonate during this ten-minute period because it was hidden between the two females. As the circling continued, L38 and the unidentified whales departed to the south. Eight whales remained, including the neonate.
At 1701 hrs, the circling stopped temporarily, with the neonate in the middle of the group. Amidst high-speed surfacing, splashing and tail lobbing, the neonate was lifted partially out of the water several times, by other whales surfacing beneath it. The neonate porpoised away from the group, which quickly followed behind. Twenty seconds later, the neonate was again between the two adult females and the group began milling. At 1710 hrs, during renewed high-speed swimming, the neonate was flipped about 3/4 of the way out of the water. Milling was then interspersed with quick movements and splashing. At 1711 hrs, activity increased, and one whale tail lobbed near to, or on top of, the neonate. At 1712 hrs, one whale and the neonate spyhopped simultaneously. The neonate, with its dorsal surface toward the adult's belly, was lifted partially out of the water by the other whale. We noted a porpoise leap and another spyhop, as the group engaged in particularly vigorous (high-speed and percussive) swimming. At 1713 hrs, the neonate tail lobbed several times in a row, just before another whale surfaced beneath it. They continued swimming in circles, sometimes passing under the boat. At 1717 hrs, one or more whales came up under the neonate, causing it to slide off their back(s) as they rose. At 1720 hrs, in an abrupt change of activity, the group began to travel south at high speed (about 10 knots) in a straight line, with no long dives. The neonate was occasionally visible during this time, largely obscured between the same two whales (L55 and L27) which were typically less than 2 m apart. Over an hour later, at 1830 hrs, the group's behavior had not changed and we discontinued observations approximately 11 km from where the whales were first sighted.
Similar to the beluga birth reported by Béland et al. (1990), we first observed the neonate when it was lifted above the water's surface on the heads of other whales in the group. We presumed, as did Béland et al. (1990), that parturition occurred beneath the water. Immediately prior to this, we noted that one whale rotated quickly, as was seen by Asper et al. (1988) and Jacobsen (1981) immediately prior to killer whale births. To the best of our knowledge this rotating behavior has not been reported in any other context. As with Jacobsen's (1981) report of the birth of a wild killer whale in Johnstone Strait, British Columbia (a "resident" from a different population), the birth occurred amongst a group of animals that displayed considerable percussive activities. On several occasions, the neonate was thrown part-way into the air, and once one or more whales in the group tail lobbed on top of, or very close to, the neonate. These actions appeared almost aggressive in nature. Similar to Weilgart and Whitehead's (1986) assessment of comparable behavior during a sperm whale birth, we interpret these types of actions as potentially stressful to the neonate. Swimming repeatedly in a large circle is unusual for "resident" killer whales in this area, but interestingly this behavior was also reported by Béland et al. (1990) following the birth of a beluga, and unusual swimming behavior was noted by a captive killer whale shortly before giving birth (Asper et al. 1988). The sustained high-speed swimming during the latter part of our encounter is noteworthy considering the presence of a neonate only about an hour old. Based on our experience with this population, we conclude that the behavior of this group during the entire encounter was unusual. Similar behaviors may provide cues for future observers for detecting parturition events.
This summer birth is somewhat atypical, in that while "resident" killer whales give birth year-round, there is a significant fall and winter peak (Olesiuk et al. 1990). The event is particularly meaningful because of the long history of research on this population of killer whales. Information is available on the age and maternal relatedness of the identified whales. The infant is the first known calf for the mother, who, at 13 years of age, was younger than the average age at first birth for "resident" killer whales (15 years - Olesiuk et al. 1990). Most of the identified whales were closely related to the mother (not an unusual situation for "resident" killer whales at any time; Bigg et al. 1990). Many of these whales were in direct physical contact with the neonate within minutes of birth.
Researchers at The Centre for Whale Research have designated the calf L82 and have determined that she is female (Ford et al. 1994). She has been seen regularly in the six years since her birth and, as with all "resident" killer whales in this population, maintains close contact with its mother and other members of its natal group.
ACKNOWLEDGMENTS
We would like to thank Alex Rhodes, Seacoast Expeditions, Victoria, for use of one of the observation boats, and Larry Dill, Simon Fraser University, for use of the other. Dave Ellifrit (Center for Whale Research, Friday Harbor, WA) identified whales from our photographs and provided unpublished data on sightings prior to our observations. RWB was supported during this period by Simon Fraser University, and field research activities were supported by Larry Dill and the Natural Sciences and Engineering Research Council of Canada (grant to L. Dill). We thank Glen Hvenegaard and two anonymous reviewers for editorial suggestions.
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