Orcas

Dt'S Animal

A whale is a mammal, just like humans, dogs, cats, horses, and elephants. They have lungs similar to all other mammals, and must breathe air. Whales have either one or two blow holes on top of their head, like a nose, they breath through. Whales cannot breath through their mouth like land mammals, the mouth is for eating. Whales cannot absorb oxygen from the water like fish.

Whales, dolphins and porpoises belong to the same order of mammals, called cetaceans and are divided into two groups. Odontocetes (toothed whales), and mysticetes (baleen whales).

Odontocetes include dolphins, porpoise, Orca and sperm whales. Many of these types of whales are found in strong family groups called pods. Odontocetes have only one blowhole.

Mysticetes whales have two blowholes, and hundreds of baleen plates which are attached to the upper jaw instead of teeth.The baleen is made of keratin, just like a human fingernail, and is used as a strainer allowing the water to pass through and trap the small fish, krill and plankton inside the mouth so they can be swallowed. Humpback, Gray, Blue and Bowhead are mysticetes whales. Baleen whales do not live in family groups, but often will temporarily gather into small communal feeding groups. A mother and calf will usually stay together one to two years.

Whales are warm blooded, just like humans (body temperature 96 degrees), but have a very thick layer of fat (blubber) to insulate them from the cold arctic water of the oceans where they feed. Most whales migrate to the warmer tropical waters for breeding and birthing their babies. Whales become pregnant and have live calves. Gestation period is about 11 months for Humpback Whales. Females produce milk to feed their young, just like humans. Calves are born with no body fat. They drink mother's milk, which is about 50% fat, gain weight and create an insulation layer very quickly. Calves gain about seven pounds per hour for the first month.

Whales have extremely powerful tail muscles (peduncle) and tail fins (flukes) which they wave in the water to swim. Some whales can swim at speeds over 20 miles per hour. This allows them to migrate from tropical waters, like Hawaii, to the colder waters, like Alaska in as little as 30 days. There is less oxygen and more salt in tropical waters and therefore less plant growth and less prey species for food. For this reason the whales must migrate to colder waters where food is abundant. It is estimated that a mature humpback whale may gain as much as 15,000 pounds in a single summer. They may lose most of that during the migration and while in their breeding and calving grounds since they do not feed and the mothers will be producing milk from their fat.

HUMPBACK WHALE DISTRIBUTION AND MIGRATION:

Humpback whales can be found in all of the worlds oceans, but are usually identified in four different groups: North Pacific, South Pacific, North Atlantic, and South Atlantic. Most populations of humpbacks follow regular migration routes, summering in temperate and polar waters for feeding, and wintering in warmer tropical waters for calving and breeding. The North Pacific Humpbacks have three primary wintering grounds: Japan, Hawaii, and Mexico. The whales that winter in Japan usually summer in the Bering Sea, and do not usually intermingle with the Hawaiian and Mexican whales. The Hawaiian and Mexican whales will summer in the Western Gulf of Alaska, or in Southeast Alaska. Currently there is an estimated 11,000 to 13,000 Humpback Whales in the world. This number represents about 15% of their original population. The International Whaling Commission classified them as an endangered species in 1966, giving them world-wide protection. Out of that number there is an estimated 600 whales that will summer in or near Southeast Alaska. Southerly Migration and Wintering occurs between November and March. The Northern Migration and Summer feeding are from April through October. Not all humpback whales migrate to the tropical waters Some remain in the winter feeding grounds all year.  These may be older whales that are past breeding age or young whales who have not reached maturity yet.There is not enough food for the humpbacks to feed on in the tropical waters, hence the reason for the migration to the north is to eat.The sub-arctic waters waters of the feeding grounds are too cold for newborn calves to survive in. They are born with no body fat for insulation. Solution is to migrate to the warmer tropical waters for calving.  With gestation at 11 1/2 months breeding coincides with the calving period so males that wish to breed migrate also.

SPECIFIC HUMPBACK WHALE INFORMATION

PHYSICAL DESCRIPTION:

The Humpback whales head is broad and rounded when viewed from above, but slim in profile. The body is not as streamlined as other whales of its type, instead it is quite rounded at the head, narrowing to a slender but powerful peduncle muscle in the tail. The top of the head and lower jaw have rounded, bump like knobs, called tubercles, each containing at least one stiff hair. The purpose of these hairs is not known, however it is believed to provide a sense oftouch. There are between 20 and 35 ventral grooves, which extend from the front jaw to beyond the navel. These expand much like an accordion allowing the whales to engulf as much as 1500 gallons of water and feed.

COLOR:

The body is black on the upper side, and mottled black and white on the under side. This color pattern extends to the flukes. The mottled pattern on the flukes is distinctive for each whale, like a fingerprint, allowing identification of individual whales. This pigmentation varies from all white to all black. The pectoral fins also vary from all black to all white.

FINS AND FLUKES:

About 2/3 of the way back on the upper body is an irregularly shaped, small, dorsal fin. The pectoral fins are very long (up to 16 feet), between 1/4 and 1/3 the length of its body, and have large knobs on the leading edge. The flukes can be as much as 18 feet from tip to tip, are serrated along the trailing edge, and usually pointed at the tip.

LENGTH AND WEIGHT:

Adult males measure 12.2 to 14.6 meters (40 to 48 feet). Adult females measure 13.7 to 15.2 meters (45 to 52 feet). The weight will vary but averages about one ton per foot, or 45 tons.

COMMUNICATION (SINGING):

Perhaps the most interesting behavior of Humpback Whales is their singing. Scientists have discovered that Humpbacks sing long complex songs. They have learned that all the whales in the North Atlantic sing the same song, and all the whales in the North Pacific sing the same song, the songs of each of these different populations, and those of other areas of the world, are all uniquely different. A typical song lasts from 10 to 20 minutes, is repeated continuously for hours at a time, and changes gradually from year to year. The sounds range from clicks and grunts to ethereal squeals. It is interesting to note that the Humpbacks are the only animals to have two hit records. ASongs of the Humpback Whale@ and ADeep Voices@ both on Capital records.

MATING AND BREEDING:

Humpbacks reach sexual maturity at 5 to 8 years of age. Males at 5 or 6 years of age and females at 6 to 8 years of age, the average length at this age is 11 to 12 meters (36 to 40 feet). Each female may bear a calf every 2 to 3 years and the gestation period is approximately 112 months. A Humpback calf is between 4.5 to 5 meters (10 to 15 feet) long at birth, and weighs 12 to 2 tons. It nurses frequently on the mother's rich milk, which is 45% to 50% fat. Weaning usually takes place between August and October of the calf's first year. A calf usually stays with its mother less than two years.

FEEDING BEHAVIOR

Whales have developed a variety of feeding techniques. The Humpback Whale is a baleen whale, which is known as a rorqual whale. This means that they have ventral grooves on the lower side of their jaw and neck. These grooves will expand like an accordion when the whale is feeding, allowing it to take in hundreds of gallons of water and prey. The whale then closes its mouth and uses its tongue to force the water out through the baleen plates trapping prey (food) inside. The most spectacular type of feeding by Humpback Whales is called bubble net feeding. Often we will see from one to ten whales performing this technique together. The whales will sing and blow a ring of bubbles below the water scaring and trapping the prey (usually herring) in a tight school inside the bubble net. After this is accomplished the whales swim up through the school of fish with their mouths wide open and lunge out of the water while closing their mouths. Sometimes they will lift a third of their body out of the water. Observers watching a group of whales perform this maneuver consider it to be totally awesome. The main diet of Humpback Whales consists of a variety of prey such as krill, herring, capelin, sardines, mackerel, sand lance, and other small schooling fish.

The most common whale in the Southeast Alaska area is the Humpback. Orcas are sighted often, and occasionally Minke and Gray Whales. Humpback Whales are usually quite active and provide excellent whale watching opportunities. They can be observed slapping their flippers (pectoral fins) on the water, lunge feeding, bubble net feeding, lob tailing, spy hopping, and breaching