Whales / Cetacean FAQs
What is a cetacean?
Whales, dolphins, and porpoises are in an order known as cetaceans. They are fascinating to many people, possibly because of their size, their playful-seeming activities, or the attention to human threats to these animals. Like humans, these creatures of the sea breathe air, are warmblooded, and bear live young (called calves) which are nursed by their mothers.
Click on the questions below to see the answers.
The humpback whale is often seen by whale watching boats. The humpback reaches a maximum length of 18 meters (about 60 feet) and a maximum weight of about 40 tons, with females larger than males. In the southern hemisphere its primary food is krill. In the northern hemisphere it eats schooling fish such as anchovies, cod, sand lance, and capelin. The humpback is one of the most popular whales for whale watching on both the east and west coasts. It is the whale most often photographed leaping out of the water (called breaching) and surfacing quickly to trap food, which is known as lunging. The humpback is also called the "singing whale." A male's song may be as long as half an hour and changes from year to year. According to the most recent Stock Assessment Reports the North Pacific humpback population estimate is 22,000, the North Atlantic population is 12,000; the southern hemisphere population is about 50,000.
The blue whale may be the largest animal ever to inhabit the earth. Blue whales can grow up to 31 meters (100 feet) -- roughly the length of a basketball court. Blue whales have weighed up to 146 metric tonnes (160 tons). They feed on small shrimp-like crustaceans. The whales consume up to eight tons of these animals a day during their feeding period. The loudest sound ever recorded from an animal was produced by a blue whale, and some scientists have speculated that they may be able to remain in touch with each other over hundreds of miles. The number of blue whales was severely depleted by whaling. Due to commercial whaling the size of the population is less than ten percent of what it was originally.
The fin whale is the second largest whale, reaching lengths of up to 27 meters (88 feet) and weights up to 69 metric tonnes (76 tons). Depending on where they live, fin whales eat both fish and small crustaceans. In the Antarctic, their prey is almost exclusively krill. In northern areas they often eat small schooling fish such as herring or anchovies. Like the other great whale species, the population of fin whales was severely depleted by whaling.
The right whale got its name because it was the "right" whale to hunt--it was slow moving and floated after being killed. It is the most endangered species of whale off of the U.S. coasts. It was the first whale hunted by American whalers, and it was so depleted that it has not recovered despite being protected for over 50 years. The maximum length of right whales is about 18.6 meters (60 feet), and the maximum weight is slightly more than 91 metric tonnes (100 tons). They feed on large schools of crustaceans, specifically copepods and krill, and may feed on small fish near the ocean floor. The main causes of death in right whales are entanglement in fishing gear and vessel strike. Check out our interactive Google map to see where right whales have been sighted recently.
Cetaceans feed on a variety of species from the entire food chain from tiny zooplankton to other large mammals. Some species feed on the swarms of zooplankton (copepods and euphausiids, or "krill"). Others feed on schooling fish. The sperm whale feeds on squid. The type of prey may determine how a specific species feeds. Some whales feed by lunging; they take huge gulps of water containing their prey. Others are skimmers; they swim along with their mouths open before straining out their prey. One of the more interesting feeding methods has been observed in humpback whales. They sometimes construct bubble nets around a school of fish and then lunge up through the bubble net to get their food.
The diet of bowhead whales consists of small crustaceans termed copepods and euphausiids (krill). As with other species, the bowhead whale was severely depleted by commercial whaling. It may be as long as 18-20 meters (60-65 feet) and weigh as much as 109 metric tonnes (120 tons). Alaskan Inuits still harvest about 50 bowheads each year for subsistence use.
Unlike the other great whales on the endangered species list, the sperm whale is a toothed whale. It is the largest of the toothed whales, reaching a length of 18.5 meters (60 feet) in males and 12.5 meters (40 feet) in females. Sperm whales are noted for their dives, which can last up to an hour and a half and go as deep as 3.3 kilometers (2 miles) under the surface. An endangered species, its estimated global population is 100,000. Sperm whales feed mainly on squid, including the giant squid.
Most of the larger whales have a very low reproductive rate; females only have a single calf every 2-4 years. With very small populations, this low rate of reproduction means that it may take decades for some species to recover to their former population levels. Even under the best conditions, it will take over a hundred years for the right whale to recover.
For most large whales, the calves are born during the part of the annual cycle when the animals are in warmer waters, and the adults are not feeding. The calf typically remains with it's mother for a year before becoming independent. During that time, a calf gains weight very rapidly. Whale milk is very rich, and a blue whale calf may gain almost 200 pounds per day.
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Although commercial whaling currently does not present a threat to the survival of the baleen whales, loss of habitat and other human activities may make recovery more difficult. Collisions with vessels, oil spills and other changes in water quality, coastal development, and increasing noise created from the use of oceanic resources may all affect the whales.
Fisheries may affect whales in two ways. First, whales may become entangled in fishing gear. As an example, each year several humpback whales are entangled in fishing gear along the east coast of the United States and Canada. Second, fisheries may compete with whales for food, such as herring.
Increased noise or boat traffic may cause whales to alter their behavior. There is evidence that humpback whales in Hawaii may have changed their use of near-shore waters where calves are raised by their mothers because of increasing human activity. Migrating bowhead whales may move further offshore to avoid human-caused noise.
Although we do not have a full understanding of the possible impacts, pollution could also affect whales. Many contaminants are stored in a whale's blubber for long periods of time. Pollutant loads are usually lower in baleen whales than in dolphins and porpoises. Deterioration of the environment could possibly affect the whales in another way: if pollution and other factors reduce the number of fish and crustaceans, the food available to the whales could also be reduced.
In the eastern North Pacific Ocean, the harbor porpoise ranges from Point Barrow, along the Alaskan coast, and down the West Coast of North America to southern California (Gaskin 1984). The harbor porpoise is basically an inshore species, frequenting coastal waters and the mouths of large rivers, harbors, and bays, sometimes ascending freshwater streams. Relatively high densities of harbor porpoise have been recorded along the coasts of Washington, and Northern Oregon and California; yet, distinct seasonal changes in abundance in these areas have been noted, possibly due to a shift in distribution to deeper offshore waters during winter.
There are seven species of large cetaceans in US waters that are protected under the Endangered Species Act. They are the blue whale, the bowhead whale, the fin whale, the humpback whale, the North Atlantic right and North Pacific right whale, the sei whale, and the sperm whale.
Thanks to Christin Khan and Allison Henry of the Protected Species Branch for fact-checking and editing this page.
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