A pod of seals makes its way back to the shore from hunting in order to return to their resting grounds. Exhausted from the hunt, they push themselves through the icy cold waters to the best of their ability. Unbeknownst to the pod, however, a group of large predators have been tracking them down throughout the return trip. An older seal begins to decelerate, unable to keep up with the younger individuals. As it begins to near the shore, it senses a sudden disturbance in the water. Before any reaction could take place, the water explodes beneath it, and the seal is clenched in the jaws of a leviathan, a great orca. The other seals witness the event, and begin to speed their way to shore. Suddenly, another seal is ambushed as a second orca erupts from the water beneath it and clamps its jaws around it. The already violent waters become a torrent of red foam as the attack continues. The remainder of the seal pod makes it to shore, stricken with great fear. In the distance, they witness the corpses of their former pod members flung viciously around by the orcas. They large predators almost seem to make a game out of this hunt, and the morbid sport goes on for several minutes before the dead seals and the orcas disappear beneath the surface. These waters are not under the domination of sharks, but of much larger predators. These waters are dominated by the orcas.

Sporting an incredibly high aptitude and enough force to overpower and kill a great white shark, the orca (Orcinus orca) has become one of the most triumphant of predators and reigns at the top of the marine food chain. Also known as the killer whale (a misleading name, as they are actually members of the dolphin family), these massive marine mammals form strong social bonds, travel in sizable groups called pods, and are capable of cooperating effectively in order to catch food. Orcas have been documented breaking up ice floes holding resting seals, pushing the body of ice into deeper water, and creating strong waves to force the seal into the water for the orcas to prey on.[1] These qualities make them among the most respected predators in the world, and their use in marine theme parks has only added to their fame. Their combination of charisma, strength, and beauty make them attractive to most people, while their intelligence and complex social behavior make them especially appealing to scientists. They are important creatures to indigenous cultures such as the Kwakwaka’wakw, where they were seen as rulers of the undersea world with sea lions and other dolphins as their subordinates.[2] These animals have clearly made their awesome power known to all who have had the honor of observing them, and only the admiration humans have of their beauty and grace matches the respect that is due for their strength.

These marine mammals belong to the order of Cetacea, which includes whales, porpoises, and other dolphins. More specifically, the orca belongs to the family Delphinidae, which includes all oceanic dolphins. It is the largest member of the family, and one of the most distinguishable due to its coloration and white spot above each eye. Finally, the orca species comes in three major varieties, the resident, transient, and off-shore types.[3] The types are discernible due to the physical, dietary, and social differences between them. The resident type populates the northern Pacific (sightings span from California to Russia) and mostly feed on fish and squid.[4] The dorsal fins of these orcas are round and curved at the tip. This group also appears to be the most common of the three due to the frequency with which they are spotted. The transient variety prefers to feed on marine mammals such as sea lions and lives in noticeably smaller families than their previously mentioned relatives, rarely consisting of more than five or six individuals.[5] These guys populate the northeastern Pacific and their dorsal fins are much more straightened than those of the resident type. Little is known about the remaining off-shore species, as they are rarely seen compared to the other two. As their name suggests, they rarely venture close to shore. They have at least been documented preying on fish and sharks. Furthermore, they appear to have the greatest geographic distribution of the three types, occurring in the Northeastern pacific but also entering inland waterways in Canada. They seem to be fond of traveling in rather large groups containing as many as 75 individuals, but occasionally reaching as many as 200 members.[6]However, although a great number of orcas are present in the Pacific, they have been spotted throughout the world’s seas, from the Arctic down to the Antarctic zones.

Male orcas can grow to lengths of 25 feet and weigh up to 6 tons (though larger specimens have been recorded). Females are somewhat smaller, growing up to 23 feet and weighing closer to 4 tons. Despite their large sizes, killer whales can be surprisingly fast, reaching top speeds of 30 mph. They are also capable of porpoising, where they repeatedly launch themselves out of the water in the direction they are swimming (this style of traveling conserves energy).[7] Mature males can be easily discerned from females due to their much larger pectoral fins as well as different color patterns in the genital area.[8]’[9]

Like other cetaceans, orcas locate their prey through echolocation. That is, they project high-pitch sound waves which bounce back from nearby objects as an echo which the orcas can interpret upon reception. This useful tool gives the orca an edge over most of its prey, allowing them to locate food and set up an ambush before the prey can notice the predators. Sound is used for more than just locating food, however. Orcas are highly social animals which communicate with each other with a wide range of sounds. These can include simple squeaks and clicks as well as powerful, high-pitch screams. The meanings of many of these calls are as of yet unclear, but the communication abilities of these creatures can be rather extreme, with some clicks reaching as many as 4000 pulses per second.[10]Studies on the differing dialects and behaviors between groups of orcas have led to the incredible possibility that orcas may actually possess a simple form of culture.[11]

Orcas have a wide selection of prey to choose from. As mentioned previously, many will commonly go after fish such as salmon, herring, tuna, and halibut. Others prey on marine mammals such as seals, sea lions, and even their relatives such as porpoises and other dolphins. In fact, on rare occasions orcas will hunt and kill large whales.[12]Orcas are also a known predator of sharks, including larger species such as the mako shark and great white shark.[13] A single orca can overpower a large shark, and is the only known predator of great whites in the wild. Sharks are sometimes killed by orcas by means of tonic immobility induction. In other words, the orca will hold onto the prey while keeping it upside down, rendering them immobile and unable to breathe (most sharks need to swim in order to breathe properly). A much more common treat is the stingray. Stingrays hiding under sand are usually dug out by the orcas and then killed. By far the most common bird prey is the penguin. Although a small meal, penguins are high in fat, which the orcas need in order to survive in cold waters. When hunting herring, orcas scare the school of fish into a ball by letting out bursts of bubbles or flashing their white-colored undersides. Once the herring are forced into this ball formation, the orcas slap the school with their flukes, stunning or killing several fish at once. The orcas then enjoy easy pickings of herring. This is called carousel feeding.[14] On many occasions, these clever creatures will even beach themselves momentarily in order to grab a nearby seal and then work its way back into the water. Orcas will also sometimes spy hop, an act where the animal rises partially out of the water in a held position in order to locate nearby prey more effectively. Orcas can hunt alone or in packs. Hunting in packs allows for the pursuit of incredibly large prey such as whales, and has earned them the title of “wolves of the sea.”With the combination of power, intelligence, and cooperation, orcas dominate the ocean. It seems nothing is safe from them, not even the largest of sharks.

Orcas seem to enjoy the unusual activity of flinging their captured prey around, whether alive or dead. They will either throw prey with their mouths or slap them into the air with their flukes (the fin-like lobes at the end of their tails). Scientists are not quite sure what purpose this odd activity serves, or if there even is any purpose other than for the sake of enjoyment.

Orcas usually reach sexual maturity at around 10 years of age.[15]Females will give birth once around every 5 years (usually during winter), and the gestation period can last as many as 18 months. The calf is weaned until it is about two years old. One interesting detail about orca parenting is that the entire pod will care for the offspring, ensuring them higher chances of survival. Females will continue to breed until they reach 40 or so years of age.

Orcas live long lives, with females possessing longer life spans than males. While males can reach 30 years of age, females are known to live for 50 years. However, life spans may vary from one region to another. Although there are reports of much older individuals, there is currently an uncertainty as to how long these creatures can live at maximum.[16]

As a result of their high intelligence and splendor, orcas have been taken from the wild and transported to aquariums and theme parks over the course of several decades. Although a wonderful experience to viewers, orcas unfortunately do not fare very well in captivity. Captive orcas become more susceptible to disease and seem to have shorter life spans.[17] These are clear signs that the species is not fit for captivity. It is also very difficult to reintroduce them back into the wild, due to major differences between social groups in captive and wild orcas. Possibly as a result of stress, captive orcas occasionally react aggressively to trainers. This has occasionally resulted in attacks, some of them fatal. Indication confirms that orcas are not fit for confinement, and live healthier lives in the feral sea.

Orcas are incredible, unique animals. With their great power and cleverness, they have dominated the oceans. With their beauty and grace, they have captivated the minds of many people. Thankfully, the populations of these marine mammals are stable, which cannot be said for many other cetaceans. They are a prime example of intelligent and beautiful animals. There is much left to learn about them, but one can only observe them in amazement as we learn about the fascinating lives these creatures lead.

---

[1] Kaplan, Matt. “Unique orca hunting technique documented.” (2007): Nature Publishing Group. [Database online.] 14 Dec 2007.

 

[2] Francis, Daniel; Hewlett, Gil (2007). Operation Orca: Springer, Luna and the Struggle to Save West Coast Killer Whales. Madeira Park, B.C.: Harbour Publishing.

[3] Whale-Images.com. “Killer Whale Information Facts Pictures.” Whale-Images.com. Available from http://www.whale-images.com/info/killer-whale-facts.htm. Internet; accessed 4 February 2011.

[4] Berta, Annalisa; Sumich, James L.; Kovacs, Kit M. (2006). Marine mammals: evolutionary biology. Academic Press. p. 387.

[5] Carwardine, Mark (2001). Killer Whales. London: BBC Worldwide Ltd.

[6] “Killer Whale (Orcinus orca).” NOAA Fisheries, Office of Protected Resources.

[7] “Killer Whales.” www.Seaworld.org. Available from http://www.seaworld.org/animal-info/info-books/killer-whale/adaptations.htm. Internet; accessed 6 February 2011.

[8] “Killer Whale (Orca).” American Cetacean Society. Available from http://www.acsonline.org/factpack/KillerWhale.htm. Internet; accessed 6 February 2011.

[9] Ford, John K.B.; Ellis, Graeme M.; Balcomb, Kenneth C. (2000). Killer Whales, Second Edition. Vancouver, BC: UBC Press. ISBN 0-7748-0800-4.

[10] Ibid

[11] Marino, Lori; et al. (May 5, 2007). “Cetaceans Have Complex Brains for Complex Cognition“]. PLoS Biol. 5 (e139): e139. doi:10.1371/journal.pbio.0050139. PMID 17503965. PMC 1868071. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1868071/. Retrieved 2011-02-06

[12] Le, Phuong. “Tourists see orcas attack gray whale.” (2010): MSNBC.com.

[13] Turner, Pamela. “Showdown at Sea.” (2004): National Wildlife Federation. 01 Oct 2004.

[14] Chadwick, Douglas H.. “Orcas Unmasked.” (2005): National Geographic. Apr 2005.

[15] “Killer Whales.” www.Seaworld.org. Available from http://www.seaworld.org/animal-info/info-books/killer-whale/reproduction.htm. Internet; accessed 6 February 2011.

[16] Ibid

[17] Wildlife Disease Association. “Reported Causes of Death in Captive killer Whales.” Journal of Wildlife Diseases. Available from http://www.jwildlifedis.org/cgi/content/abstract/15/1/99. Internet; accessed 6 February 2011.