Orca Information

Classification Location Population Description Adaptations Eating Habits Communication Reproduction Methods of Getting Prey

Classification

Killer whales have a very simple scientific classification. They belong to the animal kingdom, and are included in the phyla chorodata. Orcas are mammals meaning they class Mammalia. Their order is Cetacea, which all whales belong to. Cetacea can further be divided into three subdivisions: Odontoceti (toothed whales), Mysticeti (baleen whales), and Archaeoceti (now extinct). Killer whales belong to the subdivision Odontoceti. Along with dolphins and porpoises, orcas belong to the family Delphinidae. They are the largest in their family. There genus Orcinus and their species Orca define exactly what they are.

Location

Killer whales travel in all oceans of the world, but mainly stay up North in the cooler waters. They are found in both open oceans and coastal waters. Their boundary is the Arctic Ice Line.

Orcas, needing the water to balance out their weight must stay in the water. If they do not their body weight will crush their lungs resulting in suffocation.

Population

The worldwide population of killer whales is unknown, but one obvious fact is that they are not endangered. Researchers believe that regional groups, or pods, exist. They identify these regional groups by call patterns, body shape, and coloration. There are an estimated 180,000 killer whales in the Arctic, and 330 in British Columbia. Johnson Strait, having 260 killer whales, is the home of 12-15 residential pods, and 15 transient pods. In the North Pacific, residential pods have 5-50 individuals. The transient pods have 1-7 individuals.

You are probably now asking what the difference is between a transient pod, and a residential pod. A transient pod does not stay in a certain region permanently. They have from one to seven individuals in them, and they are always traveling. Residential pods are completely the opposite. They permanently stay in one region and usually have more then 50 individuals in them.

A pod is a group of orcas that stick together. It can be compared to a herd of cows. Each pod contains one adult male, and several adult-breeding females. It also has a large number of sub-adults of both sexes. Large pods can have over 50 whales in it! Smaller pods, having anywhere from four to seven whales in it, usually die out within the first generation. Sometimes smaller pods join together to make bigger pods.

Description

Orcas, obtaining great camouflage, have a distinct coloration on their sleek stream lined body. The "eyespot", belly, and area under the mouth are a brilliant white. Behind the dorsal fin is the "saddle" which is gray. The rest of the body id jet black. A distinct boundary separates the black and white areas.

Killer whales skin, being hydronomic, and smooth, feels similar to wet rubber.

A male orca can grow to be 22-27 feet long and can weigh anywhere from 8,000-12000 lbs. During the change to adulthood , young males gain a tremendous amount of weight. Their flippers, dorsal fins, and tail flukes begin to grow proportionally larger. The largest male recorded so far was 32 feet long and weighed 21000 lbs.

Females can reach 17-24 feet long and weigh from 3000 to 8000 lbs. The largest female recorded was 28 feet long, weighing 15000 lbs.

The paddle-like pectoral flippers help orcas steer and stop. Inside, they contain the major bones found in the fore limbs of land animals except they are shortened. The bones, which are rigidly connected by connective tissue, have thick cartilage pads laying lengthwise between them.

Unlike the tail flukes, flippers do not provide the whale with any power. Instead, the broad, flat flippers can be used as a form of communication. A male's pectoral flippers can get to be six and a half feet long and four feet wide.

The flattened horizontal lobs of the tail are called the tail flukes. A males' tail flukes may measure nine feet from tip to tip, A fluke, having no bone, is made up of dense connective tissue. Powered by two large muscles, one below the base of the tail and one above, the tail provides propulsion for the whale. The up and down motion propels the whale through the ocean. Like pectoral flippers, the tail flukes can be used as a type of communication and signaling.

The dorsal fin, acting as a keel, stabilizes a whale as it swims. The dorsal fin is boneless and is made up of dense fibrous tissue. It is located in the middle of the back. Males' fins are tall and triangular, reaching up to six feet tall! Females' fins are smaller and slightly curved back. They can get from 3 to 4 feet tall. Transients' dorsal fins are more pointed then those of residential pods. Both can have irregularly shaped dorsal fins leaning to the left or right.

On the head of a killer whale is a rostrum, or beak-like snout. Their eyes are about the size of a cows. They are on both sides of the head, above the mouth.

Behind the eyes are small inconspicuous openings called the ears. There are no external flaps.

Orcas breathe through their blowholes. While under water, the blowhole stays in a relaxed closed position. To open, it contracts its muscular flap. The blowhole, similar to nostrils, is a killer whales opening to its lungs. Their average breath hold period is from 5 to seven minutes.

Orcas do not actually chew their food. They bite it with their amazingly sharp 48 stout conical shaped teeth. They protrude out from the gum and interlock. Their teeth can get to be up to 5 centimeters long!

Adaptations

Killer whales are perfectly adapted to aquatic life. One adaptation is their coloration. When your looking down from a boat or plane, the whales black skin blends in with the dark ocean. The white belly of the whale blends in with the light skies. The rest of the white camouflages in with the sunlight shimmering throught the sea.

Another adaptation id their smooth body. They have no hair, because if they did it would create turbulance, and they would not be able to swim as fast.

Heat is lost 27 times faster in water then in air. Whales have a thick padding of fat under their skin called blubber, to maintain a constant body temperature. Blubber also acts as an energy reserve.

Another way killer whales maintain constant body temperature is through their pectoral muscles, dorsal fins, and tail flukes. The arteries in them are surrounded with veins with cooled blood. The arteries transfer their warmth to the veins, which travel through out the whole body. The heat in the arteries come from the core of the body. The core has a temperature of about 97.5 degrees fahrenheit.

Orcas use physiological adaptations to conserve oxygen while diving. When they dive, they slow down their heartbeat. By slowing down their heartbeat they restrain the amount of blood circulating throughout their body. The blood is then pushed to the lungs, brain, and heart rather then the parts of the body that can tolerate low oxygen levels. Also, the muscles contain a high Myoglobin count. Myoglobin stores oxygen to help prevent a lack of oxygen in the muscles. A killer whale has been known to dive from 100 to 200 feet under water in the wild. The deepest dive known, under experimental conditions, is 900 feet.

Eating Habits

Killer whales are at the top of the aquatic food chain. They eat both warm blooded and cold blooded animals including: squid, birds, walruses, and some other Mysticte, and Odontocete whales. They have also been known for attacking and devouring a 100 foot whales.

Orcas eat 3% to 4% of their body weight each day. Calves eat 10% of their weight. Whales from the Antarctic eat 67% fish, 27% marine mammals, and 6% squid. The whales from the Bering Strait eat 65% fish, 20% squid, and 15% marine mammals.

Methods of Getting Prey

One thing that you see killer whales doing often is "spy-hopping". Whales do this to see the world above. They also "spy-hop" to observe their prey on land, or ice flows.

Orcas have different methods of getting prey. For instance, the technique of getting sea lions is beaching. The killer whales swim up to the sand bars and slide on them to trap the seals. They do this to get the seals out into the deeper waters. The whales mainly target the baby seals. Sometimes tragedy strikes during beaching though. Whales get too close to shore and get stuck on land. Most whales die when they get beached, but sometimes people help them get back in the water.

Another method of getting prey is echelon. They use this technique for getting seals off of ice flows. First the whale "spy-hops" to see which ice flow the seal is one. Then the pod moves forward in fast echelon. Echelon is a step-like formation in which each whale is slightly to the left or right of the one proceeding. Then the whales make a big wave splashing over the ice flow throwing the seal into the water. After that it's end of that seals life.

Killer whales are perfect for being both the hunter and the hunted. It can reach the speed of 30 knots(about 35 mph). It is the fastest marine mammal. Usually killer whales travel at slower speeds such as six or seven mph. Most sharks hunt ill or young orcas that are not fast enough to get away from them.

Communication

Killer whales are social in both captivity and in the wild. There is a lot of respect held between whales of the same pod.

Communication is very important in dark, murky waters. While in this kind of water, sight is not very useful so they use sound to navigate, hunt and communicate.

One form of communication that you've probably seen is "lob-tailing". When whales "lob-tail", they slap their tail flukes hard against the water. Other forms of communication are jumps, breaches, and pec-slapping.

In the melon part of the head, killer whales make a lot of different noises. The sounds range from squeaks and clicks to grunts and groans.

Each pod has their own dialect, or group variation of a language. The dialect id passed from one generation to the next. The sounds are usually sonar-like. It is a mean of members of the same pod staying in close contact. The whales also have divert vocalizations made in the nasal sac area.

Pod Vocalizations:
(courtesy of Dr. John Ford)
  • Residential Superpod
  • Transient Pod

    Echolocation is an ability killer whales have to send out clicks and receive and interpret the resulting echoes. The clicks last for less then one to five milliseconds. The frequency usually hits a 25-KHz peak. The clicks pass through the melon, which then transforms the sound waves into a beam. The beam is forced outward into the water in front of the whale. The sound waves made go through the water at a speed of one mile per second…four and a half times faster the sound travels through the air. The sound waves then hit an object and bounce back to the whale in the form of an echo. The sounds are received in the lower jaw, then passed through the middle ear, through the inner ear, then lastly to the auditory nerve in the brain. Many scientists still have questions about echolocation so they are continuing the research on it.

    Reproduction

    Some studies at marine zoological parks suggest that females sexually mature when they reach 25-16 feet long(about six to ten yrs). Males sexually mature at 18-20 feet long(about ten to thirteen yrs). Breeding occurs in any season, but is most common in the summer time. In the North, mating mainly happens in October, and November. In the Western North, mating seems to take place in May and July.

    A mother killer whale is in gestation for about 17 months. The calves are born through out the year. The average mother, having a low birth rate, has one baby every five years. Calves are born under water either tail first or head first. The umbilical cord snaps during or soon after delivery.

    A calve is born eight feet long weighing anywhere from 300 to 400 pounds. The parts of a killer whale that are suppose to be white are usually a milky yellowish color on new borns. The dorsal fin stiffens over the first few days.

    One way a mother takes care of her calf is by nursing. The calf suckles fom nipples concealed in the abdominal mammary slits. Calves nurse for five to ten seconds at a time,several times an hour.A calf may nurse for 12 months.

    The upper teeth start showing after about two to four months. The lower teeth show after about three to five months. Calves vocalize within days.

    ** any sounds on this page are copyrighted, therefore to use them you must ask for permission. For permission write to this address: adoption@zoology.ubc.ca



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    Greenland Eskimo's call killer whales-aardusak