Birth & Care of Young

Killer Whales

Birth & Care of Young

Gestation

  1. Gestation is about 17 months. Killer whale pregnancies at SeaWorld parks have ranged from 15.7 to 18 months.

Birth Seasons

  1. Calves are born throughout the year, with no statistical evidence for birth seasons.
  2. Specific regions may have peak birth months. For example, in the northeast Pacific Ocean, many calves are born between October and March.

Calving

  1. Just one calf is born at a time. Calves are born in the water
  2. Most deliveries observed have been tail-first, but head-first deliveries also have been observed.
  3. Based on limited data collected from populations at sea and in zoological facilities, a female may bear a calf every three to five years. In some cases, a female may not have another calf for ten years.

Calves at Birth

  1. Size estimates of SeaWorld-born killer whales suggest that newborn calves are about 2.6 m (8.5 ft.) long and 120 to 160 kg (265 - 353 lb).
  2. In the first few days after birth, the dorsal fin and tail flukes are flexible and pliable. They gradually stiffen.
  3. The light areas of some young killer whales may be creamy white to pale yellow or tan rather than white. They usually turns white by the end of the first year, though some killer whales retain the yellowish color into adulthood.

Nursing

  1. Most killer whale calves born at SeaWorld generally nurse for about a year, but may continue to nurse occasionally for as long as two years.
  2. Killer whale milk is very rich in fat.
    • Fat is an efficient source of energy to drive a calf’s high metabolism.
    • High-fat milk is an adaptation for calves to be able to quickly build a thick, insulating layer of blubber.
    • The fat content of killer whale milk fluctuates as the calf develops, increasing from about 6% at birth to 43% when the calf is about 300 days old.
  3. A whale calf suckles from nipples concealed in abdominal mammary slits.
  4. Calves nurse below water, close to the surface. The mother glides in a horizontal position with her tail arched, and the calf swims on its side with its mouth on the right or left mammary gland.
  5. Killer whale calves observed at SeaWorld began nursing several hours after birth. First successful nursing attempts ranged from 1.8 to 29.3 hours after birth.
  6. Calves nurse for about 5 to 10 seconds at a time, several times an hour, 24 hours a day. Nursing frequency peaks the first day or two following birth, at about 45 minutes total average nursing time. As a calf becomes more adept at nursing and obtains more milk at each feeding, nursing time decreases dramatically to 10 minutes per day or less after three weeks and to 5 minutes or less by 2 months.
  7. At SeaWorld, it’s possible that first-time mothers may learn how to nurse their young by observing this behavior in other mother whales. Additionally, trainers teach them how to respond when their calf attempts to nurse.

Calf Development

  1. The average growth rate of the calves in the first year was 10 cm (4 in.) per month. They were approximately 3.2 m (10.5 ft.) at one year of age and had gained 454 kg (1,000 lb.).
  2. To conserve energy, the calf swims in the slipstream of its mother.

  3. A calf begins to swim independently of its mother within days of its birth, although the mother stays close to her calf and attentively directs its movements. The baby swims close to its mother and can be carried in the mother's "slip stream", a type of hydrodynamic wake that develops as the mother swims. This helps the baby swim with much less energy and keep up with the pod.

Births at SeaWorld

  1. Killer whales have been born at SeaWorld parks in San Diego, San Antonio, and Orlando. SeaWorld’s killer whale breeding program is the most successful in the world.
    • Studying SeaWorld’s killer whales, scientists have learned a great deal about killer whale reproductive biology and calf development. The data they’ve gathered from killer whale calves and their mothers could not have been obtained without close daily interaction and observation.
    • In September 1985 a female killer whale calf was born at SeaWorld Florida. The calf, named Kalina, thrived and reached adulthood. She is the first killer whale successfully bred, born, and raised in a zoological environment.
    • In February 1993 at SeaWorld San Antonio, Kalina had a calf of her own—the first second-generation killer whale calf born in a zoological park. Kalina has borne three more calves—in 1995, 1999, and 2004.
    • To date, more than 25 calves have been successfully born and raised at SeaWorld parks.
    • On September 26, 1985, at SeaWorld Orlando, a killer whale
      gave birth to the first calf successfully born and raised
      in a zoological environment.

  2. SeaWorld experts have developed techniques for artificially inseminating killer whales. Artificial insemination (AI) occurs when semen that has been collected from a male is placed into a female’s reproductive tract.
    • The first killer whale born as a result of artificial insemination was born at SeaWorld San Diego in September 2001. The male calf was named Nakai.
      • The full details of this scientific breakthrough in whale biology and reproduction may be found at the Society for the Study of Reproduction's online journal article Biology of Reproduction, "Artificial Insemination in Killer Whales".
      • SeaWorld experts developed an intrauterine insemination technique using specialized medical instruments. They also developed a methodology for the collection and storage of viable killer whale semen.
      • Veterinarians monitored daily urine samples to track hormone levels in adult female killer whales. This, combined with ovarian ultrasound examination, indicated when a female was about to ovulate. This information helped experts pinpoint the best time to introduce the semen.
      • AI successes at SeaWorld require collaboration from SeaWorld veterinarians, killer whale trainers, animal keepers, and laboratory specialists.
      • A critical component of a successful breeding program is maintaining genetic variability. Without AI, this meant transporting whales by plane between the SeaWorld parks, pairing different females with males, and hoping for successful mating. With the development of AI, managing genetic diversity has become easier. Instead of transporting an adult whale, semen samples can be sent from one park to another.
  3. Successful killer whale births also have occurred at SeaLand of the Pacific (British Columbia, Canada), Marineland of Canada, Kamogawa Sea World (Japan), and Marineland of Antibes (France).