Tag Archives: whales

Gray Whales

Gray whales are one of the most-researched and best-understood species of whales. They are baleen whales, but unlike the whale species I’ve discussed the past two weeks, they are not rorquals in the family Balaenopteridae. Gray whales are the only species in the family Eschrichtiidae. You may recall that I mentioned that rorquals all have two characteristics in common: numerous ventral throat grooves and a dorsal fin. Gray whales do not have a dorsal fin, and they only have two to four throat grooves. They also differ from rorquals in several other ways. A gray whale has the coarsest baleen of any whale and the fewest number of baleen plates. Unlike rorquals, gray whales are predominantly suction, bottom feeders. A gray whale scrapes the side of its head along the ocean floor and scoops up sediment with its mouth, capturing small invertebrates in its baleen while expelling the sediment through the baleen fringes. Amphipods are the favorite food of gray whales. Gray whales are also stockier than most rorquals and are slower swimmers. They migrate close to shore, making them easy to watch and study.

The gray whale is one of the most ancient species of mammals, and it is estimated to have been on earth for approximately 30 million years. As the name suggests, gray whales are slate gray in color with gray and white patches on the skin. They are covered with abrasions, scars, and clusters of barnacles and whale lice, and they sometimes carry over 400 lbs. of barnacles and lice. Adults average approximately 46 ft. (14 m) in length, with females slightly larger than males. The average weight is 30 to 40 tons. A gray whale’s body is streamlined, and it has no dorsal fin but does have a dorsal hump about 2/3 of the way down the back. This hump is followed by 6 to 12 knobs extending to the tail stock. It has a narrow, triangular head that is arched downward when viewed from the side.

Gray whales have one of the longest migrations of any mammal. In the summer they feed in the arctic in the Bering, Chukchi, and Beaufort Seas, and in the fall they migrate to their calving grounds in the southern Gulf of California and Baja Mexico, a migration of 5000 to 7000 miles (8,050 – 11,275 km) each way. Their average swimming speed is only 3 to 5 mph (5-8 km/hr), so this migration takes a long time. On their northern migration, they pass by Kodiak Island in April and May, where they can be viewed from bluffs along the outside perimeter of the island. They are travelling and rarely stop to explore the deep bays on the island, and unfortunately, I have never witnessed their migration, which explains why I have no photos to accompany this post. The gray whales’ migration is considered a rite of spring on Kodiak, and is celebrated with a 10-day Kodiak Whale Fest with many activities, including guided trips to good whale-watching spots.

There are currently two gray whale populations, but at one time, there were three. The north Atlantic population is thought to have become extinct in the 17th century from over hunting. The Pacific gray whales were nearly wiped out in the 1850’s after the discovery of the calving lagoons in Mexico, but were partially protected in 1937 and completely protected in 1947, and since then, the eastern north Pacific population has made an incredible recovery and is now close to the original population size. The western Pacific stock, however, is endangered and is estimated to have only 101 individuals.

Gray whales have been impacted by ocean warming in recent years. Increasing sea water temperatures in the Bering Sea have reduced winter ice cover in the region, which has led to a reduction in productivity. Primary productivity in the northern Bering Sea declined 70% from 1988 to 2004, and the previously ice-dominated, shallow ecosystem that favored large communities of benthic amphipods (the favorite food of gray whales) has been replaced by an ecosystem dominated by pelagic fish. Gray whales have responded by migrating further north to the Chukchi Sea, but it is not certain what will happen if amphipod communities disappear from this region.

If you’ve spent time around gray whales, please leave a comment and tell me about your experience.  Also, if you are interested in reading sensational Alaskan true-crime stories, please sign up for my monthly Mystery Newsletter on my home page.

Humpback Whales

Humpback Breaching
Humpback Breaching

Humpback whales are the best-known members of the family Balaenopteridae. Like other rorquals, humpbacks have a dorsal fin, and they have ventral throat grooves running from the tip of the lower jaw to the belly, but humpbacks differ in many ways from the other species in the family Balaenopteridae, and because of these differences, humpbacks are classified in a separate genus from the other rorquals. The body of a humpback is more robust and not as sleek as the bodies of fin, sei, blue, and minke whales. The top of the head and the lower jaw of a humpback are covered by rounded bumps, each containing at least one stiff hair, and the pectoral flippers are very long, spanning one-third of the body length. The tail stalk is thin, and the tail has a series of ridges on the trailing edge. Humpbacks are slower swimmers than other rorquals, but they are more acrobatic than their cousins. They often raise their tails high in the air before diving and engage in breaching, tail slapping, flipper slapping and other physical activities. It is this acrobatic behavior, their curiosity, and their beautiful, haunting songs that make them so popular with humans.Humpback2

Adult humpbacks average 49 ft. (15 m) in length and weigh approximately 35 tons. They are predominantly black on the dorsal side and have varying degrees of white on the throat, belly, flippers, and flukes. The shape and color pattern on a humpback’s dorsal fin

Photo by Tony Ross
Photo by Tony Ross

and flukes are unique to the individual, much like a human’s finger prints. Once biologists realized this, they were able to catalog and follow individual whales during their migrations and throughout their lives, greatly increasing our understanding of humpbacks’ social, mating, calving, and feeding behaviors, as well as giving researchers a better estimate of population sizes.

The baleen of a humpback is black in color, and like most other baleen whales, humpbacks feed in high latitudes and breed and give birth in low latitudes, near Mexico, Hawaii, and in the western Pacific near Japan. We mostly see humpbacks in the summer near Kodiak Island, but a few individuals spend the winter here as well. Since humpbacks don’t reach sexual maturity until they are 5 to 7 years old, it is possible that some whales we see in the winter are not yet sexually mature, so they do not migrate to breeding and birthing areas. Humpbacks feed on krill, other zooplankton, and small schooling fish. As with other baleen whales, humpbacks feed almost exclusively during the summer months and live off their fat reserves in the winter. It has been estimated that a humpback eats up to 1.5 tons of food per day when it is feeding. Humpbacks sometimes employ a method known as bubble net feeding, where they release air bubbles while swimming in circles beneath their prey and then lunge open-mouthed to the surface through the center of the concentrated prey.

Humpbacks are known for their acrobatic displays, including breaching, spy-hopping, lob-tailing, tail-slapping, and flipper slapping, and some of these displays can last for hours, especially during mating. In a few weeks, I will discuss these behavioral displays in more detail

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Humpbacks are also famous for their long, complex songs. These songs are sung by male humpbacks in the winter, and it is believed that their primary function is to attract females, although it has also been suggested that the songs may be used between two males in order to establish dominance. All whales in a particular population sing essentially the same song, and as the song changes slowly over time, the males somehow coordinate these changes. A typical song lasts 10 to 20 minutes, but it may be repeated continuously for hours. During mating, males compete very aggressively for females, and these competitions that sometimes last several hours may involve tail slashing, ramming, and head butting. Although humpback whales are quite social during the mating season, they are usually found alone or in small groups on their summer feeding grounds.

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Next week, I will post about gray whales, one of the most-researched and best-understood species of whales. As always, I welcome your comments, and would love to hear about some of your whale encounters.

For mystery lovers, please visit my home page and sign up for my monthly Mystery Newsletter. I will be sharing details of some true-life Alaskan crimes!

Whales

Fin whales in Uyak Bay
Fin whales in Uyak Bay

Whales have been on my mind lately; probably because I’ve seen some nearly every time I’ve gone for a boat ride this summer and fall. Zooplankton and schools of small fish have swarmed the bay all summer and fall, providing abundant food for everything from larger fish, gulls, eagles, other birds, harbor seals, sea lions, and of course whales. I’m certain that if I jumped in my boat right now, within in minutes, I’d be in the midst of several huge fin whales, whose 18-ft. tall exhalations surpass any choreographed water-fountain show in Las Vegas. I’d probably also see two or three humpbacks waving their tail flukes in the air and perhaps leaping out of the ocean and slapping their large pectoral fins and tail flukes on the water.

I’ve also been thinking about whales, because that is the chapter I’m working on for my book on the wildlife of Kodiak Island. While I love whales, writing about them has been an arduous process, since little is known about many species, and I must draw bits and pieces of information from an array of sources. This painstaking research, though, has provided me with a better understanding of these huge, intelligent creatures, so I thought I would write a few posts about them. I will focus on the whales that can be seen near Kodiak Island, and I will admit that I have not seen all these species, because either they migrate past the island and do not enter the deep bays, or they spend their lives off shore. There is also another, darker reason for me to write about the whales near Kodiak Island. This summer more than 30 whales (mostly fin and humpback) died near Kodiak, and biologists are scrambling to discover the cause.

Whale species commonly found near Kodiak include fin whales, the second largest species of whale; sei whales, the third largest species of whale; humpbacks; Minke whales; and Orcas, or killer whales (although Orcas are actually dolphins, not whales). Gray whales migrate past Kodiak on the way from their breeding and birthing areas near Mexico to their northern feeding grounds, and blue whales, the largest species of whale, can be found off shore in the Gulf of Alaska. Blue whales, fins, sei whales, humpbacks, Minkes, and gray whales are all filter feeders and have baleen instead of teeth. Killer whales, of course, have teeth.

As you probably know, whales, like humans, are mammals. They have lungs and must breathe air to survive. They are warm-blooded, and like most mammals, they bear live young. Whales nurse their young with milk, and while you may not think of a whale having hair, all whales do have hair at some stage in their development. Whales are in the order Cetacea, and all members of this order are believed to have evolved from hoofed animals, such as cows, sheep, and camels, 45 million years ago.

All cetaceans have forelimbs that have been modified into flippers and no hind limbs. Their tails are horizontally flattened, and they breathe through a nostril or blowhole, located on the top of the head. Whales have internal sensory and reproductive organs to reduce drag when swimming, and cetacean mothers nurse their calves with a pair of teats that are concealed in slits along the body wall.

Cetaceans living in the cold ocean waters of the North Pacific must somehow maintain a body temperature that is nearly the same as a human’s body temperature, and a whale uses a number of mechanisms to accomplish this feat. First of all, it has a thick layer of blubber which has few blood vessels, reducing heat loss at the body surface. A whale has a counter-current exchanger, where veins at the periphery are surrounded by arteries. Heat lost by vessels flowing from the warmer core toward the cold periphery is at least partially absorbed by vessels flowing from the periphery to the core. A cetacean also has a fairly high metabolic rate to produce heat, and it has a low body surface to volume ratio, which conserves heat. Also, a whale breathes at a slower rate than a land mammal does, so warm air is expelled less frequently.

The order Cetacea is divided into two suborders: The Mysticeti or baleen whales and the Odontoceti, or toothed whales. I primarily will be discussing the Mysticetes, and next week, I’ll describe baleen and how it is used. Please leave a comment if you have any questions or would like to add anything about whales. I would love to hear about your whale experiences!

In late November or early December, I plan to start a monthly newsletter focused more on mysteries and my fiction writing. My first several newsletters will chronicle some true-life Alaska crimes. If this sounds interesting, please subscribe to my e-mail list.

Subscribe to my monthly e-mail mystery newsletter. Beginning in late November, I will begin chronicling some true-life Alaskan crimes!

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