Orca Whales

  by Krysta Cardinale

Orca whales or Orcinus orcas are part of the greater family of whales, but are classed as oceanic dolphins or toothed whales. This family includes other familiar species such as bottlenose dolphins. Orca whales are second only to humans as the most widely spread mammals on earth. Orca whales have been given the nickname “Killer Whales” because their reputation perceived them as man-eaters. The truth of the matter is, no Orcinus orca has ever been reported for attacking a human. On the other hand, the Native Americans actually held the orca very highly. They believed that it brought them health, strength, and food.

Orca Whales travel in families called pods. These pods consist of five to twenty members ranging in different numbers of sexes. Pods have been seen as big as 100 members, but this is when several pods group together for different reasons temporarily. Female Orcas also have a tendency to form their own pods with their offspring, this is called a matrilline. Orcas are considered a socially active species. They often partake in tail-slapping, head-stands, and jumping.

Physical Description of the Orca Whale

The Orcinus Orca, or Killer Whale, is the largest of the dolphin family it is classified as. The males of this species reach such sizes as large as 9.4 meters long, and the females as large as 8.5 meters. They can reach a weight of about 7 tons. All Orca whales are black with specific white sections. They have white underbellies from the chin to right before the anus. They have white oval shapes just behind their eyes, and a dark gray patch that extends up the side posterior to the dorsal fin.

Orca whales have about 10-12 teeth on each side of both jaws. These slightly curved teeth interlock when the mouth is closed. The black dorsal fin the whale has is significantly larger in males than in females, reaching a length up to 1.8 meters.

Traveling in large groups, dolphins use sound to perceive the world around them. Sonar or eco location is utilized to identify the position, size and shape of prey, and for communication. They click, squeak and groan and no two sounds are alike. Toothed whales such as dolphins and Orcas produce sounds by forcing air through their nasal passages and blowholes. They receive sound waved via the jawbone, which reverberates back to the inner ear. Their keen eyesight can be of limited use in the blackened depths of the oceans. Sound, however pierces right through it.

Reproduction Behavior

Orca Whales, like other whales are considered mammals. This is because they give birth to live calves and do not lay eggs. Depending on the sex of the Orca Whale determines the age it reaches sexual maturity. Females do not reach it until about 15 years. Female Orcas, or cows, can give birth once every five years. The gestation period, or pregnancy period, ranges from 15-18 months. Even though they can give birth at any time, most take place during the winter months. Baby Orcas, or calves, have a high infant mortality rate, and only about half of them reach six months old.

Baby Orcas nurse from their mothers for about two years. These baby orcas can, however, eat solid food after 12 months. Females can nurse young up to about forty years, allowing them about five births in their lifespan. Male Orcas become sexually mature at the 15 years as well, but does not reproduce until it is about 21.

Distribution of Orca Whales

As previously stated, Orca whales are a largely distributed mammal. They can be found in oceans all over the world, including the polar seas. In fact they actually prefer cooler waters. The only place they are rarely seen is in the Gulf of Mexico. Although they have been seen in deep waters, the Orca prefers coastal regions. Large populations of Killer Whales are native to the northeast Pacific Basin, off the shore of Iceland and northern Norway, and in the Antarctic waters.

Eating Habits

The Killer Whale is considered the ocean’s top predator. Being an apex predator, meaning it is at the top of a food chain and has no predator’s, the Orca is important in maintaining the ecosystem it is apart of. They have a very diverse diet including squid, fish, skates, rays, sharks, sea turtles, sea birds, seals, sea lions, walrus, dolphins, porpoises, and large whales such as fin whales, humpback whales, right whales, minke whales, and gray whales. They are even known to attack the sperm whale and blue whale. Orca whales in certain locations have been noted to stick to a more limited diet. For example, Orcas found in the Norwegian and Greenland seas primarily stick to Herrings.

Being an intelligent predator, Orca whales use a combination of hunting methods to capture their prey. They have used such methods as throwing seals into the air to stun them and then kill them. Other “stunning” techniques include head-butting and tail-slapping. For fish, these Killer Whales have used to techniques. They either capture fish like salmon alone, or they use a corral method with several members encircling such fish as herring. An average Orca whale will eat up to 500 pounds of a food a day.

Orca Whales and Humans

The relationship between Orcinus Orcas and humans has come a long way. Throughout the middle of the 20th Century, Orcas were hunted commercially depleting their population by great numbers. In the 1950s the United States Air Force actually used Killer Whales for target practice. Fishermen off the coast of Iceland complained that these whales were running their fishing nets. Up until about 1964, the U.S. Air Force continued to kill thousands of Orcas with their automated weapons. However, in 1981 the moratorium was passed preventing all whaling. While the Orca whales’ numbers continue to decline, the focus on them is for protection rather than massacre.

Since the late 1970s and early 1980s Orca Whales have been successfully raised and bred in captivity. Orcas in captivity have a greatly lesser lifespan than those found in the wild. For example, females found in the wild have lived well into their eighties, and females in captivity only reach their twenties. This could be due to several reasons. The large tanks used to hold these mammals bare no resemblance to the wild. Captive Killer Whales are subjected to chemically altered water, false social groupings, and small tanks. In captivity, more than half of Orca Whales develop a collapsed dorsal fin, meaning it falls and curves over to one side rather than standing straight up.