Orcas (Orcinus orca), or killer whales, are the largest of the dolphins and one of the world's most powerful predators. They feast on marine mammals such as seals, sea lions, and even whales, employing teeth that can be four inches (ten centimetres) long. They are known to grab seals right off the ice. They also eat fish, squid, and seabirds. Though they often frequent cold, coastal waters, orcas can be found from the polar regions to the Equator.

Photo Gallery
All photos copyright: ©Chiara G. Bertulli

Killer whales hunt in deadly pods, family groups of up to 40 individuals. There appear to be both resident and transient pod populations of killer whales. These different groups may prey on different animals and use different techniques to catch them. Resident pods tend to prefer fish, while transient pods target marine mammals. All pods use effective, cooperative hunting techniques that some liken to the behaviour of wolf packs. Whales make a wide variety of communicative sounds, and each pod has distinctive noises that its members will recognize even at a distance. They use echolocation to communicate and hunt, making sounds that travel underwater until they encounter objects, then bounce back, revealing their location, size, and shape. Killer whales are protective of their young, and other adolescent females often assist the mother in caring for them. Mothers give birth every three to ten years, after a 17-month pregnancy. Orcas are immediately recognizable by their distinctive black-and-white colouring and are the intelligent, trainable stars of many aquarium shows. Killer whales have never been extensively hunted by humans.

Current research objectives

  • Determine the abundance of killer whales passing by Faxaflói Bay
    An intensive photo-identification study designed to minimize violation of mark-recapture assumptions can help to minimize bias and maximize precision of population estimates

  • Determine patterns of residency of killer whales in the Faxaflói populations
    Using the photo-ID data for each year, it is possible to examine the number of days individual whales and dolphins are re-sighted; minimum residency time (the number of days between first and last sightings within the same season); and re-sighting rate (the proportion of individual whales/dolphins identified on more than one day within the same season)

  • Investigate the prevalence of cutaneous disorders in killer whales of Faxaflói Bay
    Skin diseases in free-ranging whales and dolphins have been studied using a variety of research methods including photographic identification (photo-id) surveys. Thus, photo-identification techniques can be extended to record the prevalence of certain signs of disease in whales and dolphins, and suggests that these methods could be used to complement other studies of disease in wild cetacean populations