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Frequently Asked Questions
 
 

Here are a few of the Frequently Asked Questions at the Center:


Q:  Are the whales here all summer?

A:  That depends on the type of whale.  Humpback whales typically will migrate from their winter breeding grounds near Hawaii to their summer feeding grounds in Alaska during the months of May and June.  Here they will feed on the rich abundance of krill and small schooling fish until they migrate back down for the winter months.  Killer whales are subdivided into two main types: residential and transient.  Transient whales tend to cover a wide range in the search of their marine mammal prey, where as residential feed primarily on salmon and do not cover such a large range.


Q:  Why do humpback whales breach?

A:  There are several different hypotheses about the cause of this interesting behavior.  Some suggest that it is a territorial display to ward off possible threats, such as boats that are too close, or other groups of whales.  Others have thought that perhaps the breaching is to shake off parasitic mites that live on the humpback.  Yet others believe that it is all for fun and games.


Q:  What is echolocation?

A:  Because light doesn’t travel as effectively in water as in air, some marine mammals have developed their hearing senses.  By sending out rapid and pulsing sound waves, the marine mammals are able to detect the returning sound from bouncing off an object or echo.  From this echo they can determine the shape, size, distance, speed, and even density of possible prey, thus producing an image from various sound stimulus.


Q:  What are the differences between porpoises and dolphins?

A:  The differences arise in their body shape and form.  Dolphins tend to have a more pronounced beak as compared to the curved nose of the porpoise.  Also, dolphins have a more distinct and protruding lobe on the top of their head that is used for echolocation.  Shape of the teeth, stubby body shape.


Q:  I have heard that orcas are not really whales.  Is that true?

A:  This is true.  The orca is actually the largest member of the dolphin family.


Q:  What kind of whales do you see around Petersburg?

A:  There are the seasonal humpback, and the occasional gray, minkis, sei whale, beak whale, gorgions.  Also Killer whales inhabit the area around Petersburg, but they are of the dolphin family.


Q:  How many individual humpback whales are there in the Southeast Alaska area?

A:  With an estimated 6,000 whales in the North Pacific, approximately 1,000 will feed in Southeast Alaska and roughly half of those whales, or 500, will pass through Fredrick Sound.


Q:  Do Humpback whales feed on salmon?

A:  Humpback whales have a limit to the size of their feed.  Their diet is composed of krill and small schooling fish that are less than ten inches.  In fact, there have been experiences where dead humpback whales will be washed on shore and autopsies will show a large chunk of king salmon obstructing their throat.


Q:  How do marine mammals communicate?

A:  There are several suggestions to how marine mammals communicate.  Some suggestions include the vocal calls from humpbacks, the toothed whales, seals, and sea lions.  Surface activities, may also create sounds that could be used as forms of communication between individuals.


Q:  Why do whales breach and why do they exhibit surface activity?

A:  For humpback the purpose for this exciting display of power is not completely understood, but has been suggested to be a way to lose parasites, communicate long distances, or simply play.  Orcas tend to use This behavior has been suggested to be a form of long range communication with other whales, a display of dominance, a way to observe above the water, and just for fun.  Herding and concentrating feed.


Q:  What are the bumps on the humpback’s face and neck region?

A:  The characteristic golf ball sized bumps on the head and chin of the humpback whales are called rostral knobs, or tubercles.  They are hypothesized to be sensory mechanisms to detect changes in current, temperature, and vibrations caused by the sound or movement of prey or predators.  It is also suggested that they may enhance maneuverability by improving lift and drag.

   


   
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