Longevity & Causes of Death

Killer Whales

Longevity & Causes of Death

Longevity

  1. No one knows for sure how long killer whales live.
  2. Long-term studies will ultimately answer this question. By counting growth layers in teeth, scientists find that killer whales in the North Atlantic may live to 35 years. Studies are still refining this method of aging.
  3. For unknown reasons, researchers suspect killer whale calf mortality within the first six months to be "very high." In the Pacific Northwest, for example, 43% of all calves die in the first six months. In other killer whale populations, calf mortality may be as high as 50% during the first year.
  4. The photo-identification of killer whales in the Pacific Northwest began in 1973 and provides one of the longest cetacean field studies ever.
    • When factored in at birth, the average life expectancy of southern and northern resident killer whales is about 29 years for females and 17 years for males.
    • If a killer whale survives the first six months, a female's average life expectancy is 46 to 50 years and a male's is 30 to 38 years.
  5. Currently at SeaWorld, five killer whales are older than 30 with one being close to 50. While studies continue to define the average life span of killer whales in the wild, the most recent science suggests that the life spans of killer whales at SeaWorld are comparable to those in the wild.
  6. With continued research, it is likely that differences in longevity will be found in killer whale populations around the world.

Aging Studies

  1. At SeaWorld parks, animal trainers routinely take a variety of measurements - including length, girth, and fin height - of killer whales. For a whale born at SeaWorld, experts are able to relate these measurements to the known age of the whale. This information helps provide a baseline for growth studies on wild killer whales.

Diseases, Parasites and Predators

  1. Killer whales and other whales develop stomach ulcers, skin diseases, tumors, heart disease, and respiratory disorders.
  2. Hodgkin’s disease has been seen in killer whales and stranded killer whales have shown severe atherosclerosis of the coronary arteries.
  3. Recently described disease conditions include Salmonellosis in a neonatal stranded calf and West Nile Virus in an adult. Endogenous retroviruses have also been documented within the killer whale genome. The significance of these viruses on the health of killer whale populations is yet unknown.
  4. Killer whales suffer from viral, bacterial, and fungal infections.
  5. Parasites—including roundworms, tapeworms, and flukes—may affect a killer whale’s health. In most cases, parasite infestations alone are unlikely to debilitate otherwise healthy animals, but they may harm animals that are already weakened by other illnesses or injuries.
  6. Killer whales in New Zealand have evidence of small, non-fatal cookiecutter shark bites in their skin.
  7. Killer whales are a top predator. Healthy adult killer whales have no natural predators of note.

Stranding

  1. A marine animal may strand if it is affected by a severe, debilitating illness or injury, or if it is too weak to swim or hunt for food.
  2. Killer whales have stranded in Alaska due to rapidly receding tides.
  3. On rare occasions, killer whales strand, individually or in groups (called mass stranding). Mass strandings of whales and dolphins are natural phenomena that are largely unexplained. In many cases, the stranded animals are ill.
  4. SeaWorld has helped in the rescue of many types of cetaceans, including killer whales. SeaWorld aided killer whales trapped in Barnes Lake, Alaska, and was part of the team that helped “Springer”, an orphaned two-year-old found off Canada’s northern Vancouver Island in 2002. SeaWorld assisted the Dolfinarium in Holland with veterinary care and husbandry for an orphaned and hearing-impaired rescued juvenile killer whale.