Saturday, July 4, 2009

Gray Whales and how to Identify

Gray whales appear gray with splotches of different colored abrasions, scars and barnacles on their heads and backs. The barnacles are most prevelant on the areas of the skin that are exposed to air when the gray whale breathes. The gray whale can carry over 400 pounds of barnacles and whale lice. These parasites create yellow and white patches on the whales skin.

Grays have a narrow jaw and there are 2-5 pleats on their throat to help their mouth to open and expand when they feed. Like other baleen whales, they also have 2 blow holes. Having 2 blowholes, instead of the usual 1 in most whales, allows the gray to have a varied blow. The gray will spout every 20-30 seconds and can be as high as 10-13 feet into the air. They can also produce spouts that are low and wide. Some people say their blows are heart shaped.

Grays do not have a dorsal fin, but instead a small hump with a series of knobs. They have large paddle shaped flippers and broad flukes that are 25% (one-fourth) of their total body length.

Gray whale baleen is very coarse, with 20 bristles per inch. In comparison, Sei whales have over 100 per inch. They have 300 plates of yellow-colored baleen hanging from their upper jaw.

Gray whales are medium sized as compared to other whales. Adult females are always larger than males. Full grown gray whales range from 36-50 feet (10-15m) long and weigh 16-45 tons.

How long do Gray Whales live?
The average life span is 40-50 years, with some reaching 70 years.

The only predators of gray whales are orcas (killer whales) and humans. The scarring on the gray's skin reflects the battles with the orcas. Some grays flee into shallow water while others have beached or stranded themselves to escape orcas pursuing them.

How do they communicate?
While not being know for a wide variety of sounds, the ones they make are fairly simple. Gray whale calls involve moans, rumbles and growls, with the most common being knocking sounds. These sounds range from 100 Hz to 2000 Hz, with the majority between 300 and 900 Hz. To the human ear, this is very low sounding. Low sounds travel much farther than higher pitched sounds, and allow the whale to communicate for distances over a mile or more. Gray whale sounds are much quieter than other baleen whales. Their most vocal time is during breeding season.