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  1. 2011.08.21 Orca Killer Whale
  2. 2011.08.21 Narwhal Monodon monoceros

Orca Killer Whale

Fish 2011.08.21 02:25

With sleek black backs and bright white bellies and eye patches, orcas (aka killer whales) are easily distinguishable from other aquatic animals. One of the ocean's largest predators, male orcas can grow to 9.5 m (32 ft) in length, while females are slightly smaller at 8 m (23 ft). They live primarily where the water is cold but can live anywhere from the polar regions right up to the equator. This massive range makes orcas the most widespread of all sea creatures.

True to their name, killer whales are effective hunters. They prey on seals, sea lions, fish, sea birds, turtles, octopuses, and squid. Orcas will even attack other whales, including the enormous blue whale which can measure over three times their size. They have also been known to breach the surface to grab sea lions and seals, even partially jumping onto ice floes to reach their target.

Orcas hunt in pods, or groups, in a way similar to wolves. They circle their prey and force them into smaller areas before attacking. Once cornered, the orcas take turns biting and ramming their prey.

Sending sound waves that travel underwater, orcas use echolocation as a means for hunting. The reverberating sound provides information about an object's location, size, and shape. Echolocation is also used as a form of communication. Each pod has a distinctive sound it uses to communicate among its members.

There are thought to be three types of pods: transient, resident, and offshore. Transient pods are constantly on the move following food sources. Resident pods generally stay in one area close to shore, while offshore orcas prefer the open waters. Currently, scientists are not clear as to why there are contrasting pod behaviors. Some believe it is because there are actually several species of orca, but more research must be conducted in order to test that theory.

In resident pods, killer whales of both genders will live with their mothers for their entire lives, forming matrilines. In this way, resident pods consist of very tight, stable bonds and can comprise of 10-50 whales. Offshore pods are also large, made up of 30-60 whales. Transient pods, on the other hand, tend to be smaller (around 2-5 whales), as offspring will generally leave the group when a sibling is born.

When females reach 6-10 years old, they are ready to bear young. Males need to be older to breed,

roughly around 10-13 years of age.

Mating can take place at any time of year and only occurs between members of different pods to avoid interbreeding. After 17 months of gestation, calves are born in the water tail first. Female orcas can give birth every 3-10 years.

Newborns are very carefully protected within the pod. Often younger females will help new mothers protect their calves. Orcas are also known to shelter injured or ill members of their pod from danger.

Conservation Status

At present orcas are not endangered. They have not been widely hunted by humans but are susceptible to some of the same threats as other marine mammals, including pollution, overfishing of their prey, and habitat infringement. They live an average of 30 to 50 years in the wild.

What You Can Do to Help

You can help orcas by spreading awareness about their special abilities to hunt, communicate, and live cooperatively. Write to your legislator about preserving their ocean habitat and keeping it free from pollution.

Orca Distribution

Orcas can live anywhere from the polar regions right up to the equator. This massive range makes orcas the most widespread of all sea creatures.

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Narwhal Monodon monoceros

Fish 2011.08.21 02:20

Narwhals are mid-sized whales living in the cold waters of the Arctic Circle near northern Canada and Greenland. They grow between 4 and 6 m (12-20 ft.) in length – a similar size to their relative, the beluga whale.

But they are easily distinguished from their beluga kin. Male narwhals possess a great spiraled tooth that projects from their heads. The long, hornlike tooth can reach up to 3 m (10 ft.) in length and grows continually to replace wear. Researchers are unsure of the exact purpose of the tooth. Some believe it serves as an attractive ornament for mating, while others believe it is used as a weapon to fight rivals. One researcher concluded that the tooth has the ability to detect changes in water temperature and pressure.

Narwhals also have a second tooth that measures about 30 cm (1 ft.) long, but it remains embedded in the skull. Some females have been spotted with a protruding tooth, though not nearly as long as that of the males. There have even been some males with two long protruding teeth.

Narwhals also differ from belugas in skin color. Narwhals have black and white mottled skin. Appearing to resemble the bodies of drowned soldiers, the name narwhal derives from the old Norse word nar meaning corpse.

At birth, narwhals are approximately 1.5 m (5 ft.) in length. At maturity, which is between 6 and 9 years, females grow to about 3.5 m (11.5 ft.) in length, and weigh around 1,000 kg (2,200 lb.). Males reach between 4 and 6 m (13 and 20 ft.) and can weigh 1,600 kg (3,500 lb.).

Once they are mature, females will give birth to a calf once every 3 years. The pregnancy lasts for about 14 months, and calves are born in the spring.

Like many other whales, narwhals travel in groups. Their pods average 15-20 whales. Sometimes multiple pods will meet in social groups of up to 100 whales, although it is hard to get exact numbers. Narwhals have proven difficult for researchers to tag and track, mainly due to the cold and icy water conditions and the fact that narwhals do not come very close to shore.

Narwhals feed more regularly in the winter, consuming fish like cod and halibut, shrimp, and squid. Preying on creatures primarily on the bottom of the sea, they dive on average 800 m (.5 mi.), but can go twice that. The dives last around 25 minutes. In the summer, narwhals feed rarely, having stored up enough energy during the winter feeding season. They return to the same feeding grounds each year.

Narwhals are preyed upon by polar bears and walruses if they get trapped by shifting ice. Off shore they are attacked by orcas, to whom they are also related. In the summer, narwhals are also hunted by Inuits using kayaks and spears.

Conservation Status

Narwhals are currently considered near-threatened. Exact data is not known regarding the number of narwhals in the world. There are concerns with specific populations near the coasts of Eastern Canada and Greenland due to intense hunting. Many of the areas inhabited by narwhals are also subject to drilling and mining, which produces waste that is dangerous to all animal populations.

What You Can Do to Help

One way you can help is to get involved with the Whale and Dolphin Conservation Society.

Narwhal Distribution

Narwhals inhabit the cold waters of the Arctic Circle near northern Canada and Greenland.

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