GENERAL: HOW MANY DIFFERENT KINDS OF WHALES ARE THERE? There are at least 76 documented species of cetaceans (whales, dolphins, and porpoises). They belong to two different classes, the mysticetes, or baleen whales, and the odontocetes, or toothed whales. There are 11 recognized species of mysticetes: 4 species of right whales, 6 species of rorquals (including the humpback, fin and minke whales), and one species of gray whale. However, scientists are still debating about whether there are multiple species of northern Minke and Right whales. Among odotocetes, there are 3 sperm whale species, 31 dolphin species, 6 porpoise species, 5 river dolphin species, 18 beaked whales, plus the beluga (or white) whale and the narwhal. For a recent complete list of the species, consult The Eyewitness Handbook of Whales, Dolphins, and Porpoises or The Sierra Club Handbook of Whales and Dolphins. HOW BIG ARE WHALES? Whales are, as far as we know, the largest animals ever to live on earth. Blue whales are the largest species of all whales. The largest accurately measured blue whale was 103 feet in length; the heaviest ever weighed was estimated at 150 tons including all fluids. For the most part, the baleen whales are larger than the toothed whales. After the blue whale, the fin whale is the second largest, and the largest species typically found in New England waters. They can reach lengths of up to 75-80 ft. Humpback whales in New England are considered medium-sized whales and are generally 40-50 ft. long as adults, but humpbacks as long as 60 ft. have been killed in the Antarctic. A typical humpback whale would weigh about 25 tons (50,000 lbs.). The largest toothed whale is the sperm whale (of Moby Dick fame). Adult males can grow up to 65 ft., while females are smaller at 35 ft. in length. HOW LONG DO WHALES LIVE? Scientists have not determined a good way to estimate the life span of a whale. With toothed whales and dolphins, layers of dentine laid down regularly in the teeth allow an estimation of the age of the animal, but no such technique has been found in baleen whales. Layers of wax, however, are laid down in a portion of the inner ear that can be read much like a treeıs rings. There has not yet been a way to determine whether they lay down one or two rings per year, so this method remains uncertain. Tagging studies have shown that one humpback whale was caught 36 years after it was tagged, and we currently have identified humpback whales that must be at least 20 years old. Photographic studies on right whales by The New England Aquarium in Boston, MA have revealed an adult female that is at least 67 years of age! Age estimates for baleen whales based on their demographic parameters estimate their lives to be 40-70 years, although this should be considered speculative. Dolphin species are believed to live shorter lives (20-25 years), on average, than whales. WHAT IS THE DIFFERENCE BETWEEN A DOLPHIN AND A PORPOISE? Actually, in some areas of the world the words are used interchangeably. However, there are some real differences as far as biologists are concerned. Generally, dolphins are larger, have a beaked snout, have sharp teeth and are found in large social groups. Porpoises are typically smaller than 6 ft. in length, have rounded, blunt snouts, have more rounded teeth, and are often found alone or in small groups. HOW CAN YOU TELL IF A WHALE IS A MALE OR A FEMALE? In toothed whale species, males are usually at least slightly larger than females and, in some species (sperm whales and killer whales), have more prominent dorsal fins that distinguish them from the females. In baleen whales, females are actually the larger sex, however, the size difference is very slight and not easily detectable. As a result, the only reliable technique for sexing baleen whales, for many years, was to observe the animal with a calf by its side, indicating it to be a female. Recently, however, a woman named Deborah Glockner-Ferrari discovered that humpback whales have slight differences around the genital region which can be photographed, in the field, and used to determine the sex of the whale. On known females she noted a prominent bulb or swelling (a hemispherical lobe) in the genital region that was absent on males. This technique has been substantiated by several genetic studies conducted on humpback whales which have allowed for the analysis of chromosomes to reveal an individualıs gender. Unfortunately, other baleen species do not seem to possess the same genital differences that humpbacks do, and researchers must rely solely on genetic analysis as a sexing technique. DO ALL WHALES USE SONAR (ECHOLOCATION)? Sonar is the way that many marine mammals perceive their world. It involves the animal emitting very high frequency sound waves that bounce back and tell the animal that something is there. The speed with which the sound comes back tells the animal how far away the object is. The strength of the signal tells the animal about the density, or mass, of the target. All toothed whales and dolphins use sonar regularly. However, current evidence indicates that baleen whales do not have a well defined sonar system, although there is some evidence that lower frequency sounds can be used to determine where large objects (icebergs, fish schools, obstructions) are located. MATING: WHERE DO WHALES GO IN THE WINTER? Most whale species migrate to warmer waters for breeding purposes. Humpback whales in the N. Atlantic migrate to areas off the coast of the Dominican Republic and Puerto Rico in the Caribbean Sea. Humpbacks in the Pacific Ocean migrate from Alaska and northern California in the summer to Hawaii and Mexico in the winter months. An exception to this is the bowhead whale, which summers in the Beaufort Sea (Canadian Arctic) and migrates to the Bering Sea (Alaska) for the winter. Dolphins do not always show these migratory patterns. Research in New England has also shown that not all humpback whales leave in the winter. Juvenile animals have been documented to overwinter in New England and off the coasts of North Carolina, Virginia, Maryland and New Jersey. It is not currently known where fin whales, minke whales, blue whales and the other true rorquals go in the winter. DO WHALES MATE FOR LIFE? Many people have heard or read that whales, like many birds, are monogamous. However, at this time, there is no scientific data to support this. Instead, evidence indicates that females of all species mate with more than one male throughout their lives, and the father plays no role in parental care. HOW LONG DO CALVES STAY WITH THEIR MOTHER? In most baleen species, females wean and separate from their calves after only six months to one year. During that time, calves learn a great deal from their mothers, including the migration route to and from the feeding grounds. While on the feeding grounds, a mother will give her calf a tour of several different spots within the vast feeding area where food is generally plentiful. As for toothed whales, calves usually stay with their mother for at least a year, and in many social odontocetes females stay in the same group with their mother their whole life. In addition, there are resident orcas, where both males and females stay with their mother their whole life. HOW OFTEN CAN FEMALES GIVE BIRTH? Female whales generally give birth to a calf every two to three years. If you consider that they are pregnant for 12 months and then nurse their calves (called lactating) for 12 months, this is quite a reproductive feat. Even more amazing is that we have observed some females that have given birth two or more years in a row. This means that they were both pregnant and lactating at the same time. Since both of these activities take tremendous amounts of energy for the mother, this is not observed quite as often and, when it does happen, is truly remarkable. DO WHALES EVER HAVE TWINS? We have never observed a female whale with more than one calf at a time. Old whalers have reported discovering twin fetuses in whales that they killed, but two calves have never been witnessed in the wild. We think this is due to the heavy burden that each calf places on the mother, so that she can only support one at a time. POPULATION STATUS: ARE ALL WHALES ENDANGERED? Not all whale species are presently considered endangered. Generally, the large baleen whales were heavily hunted for their meat, blubber, oils, fat, etc. As a result, all baleen whales except the minke whale were listed as endangered. However, one large baleen whale, the gray whale, which is found only in the North Pacific, appears to have recovered to its original population numbers during the last half century of protection and was removed from the Endangered Species List in 1992. Of the toothed whales, the sperm whale is considered endangered after years of exploitation for their oil. All of the river dolphin species and the worldıs smallest cetacean, the vaquita (found only in the northern Sea of Cortez), are also endangered, suffering from habitat destruction, pollution, and conflicting fishing activities. ARE WHALES STILL BEING KILLED? Today, the majority of former whaling nations belong to The International Whaling Commission (IWC) and are part of an international ban on whaling activity. Only Japan and Norway still commercially hunt whales. Their main target is the minke whale, which is not currently on the endangered species list and which is used for human consumption in these countries. Japan also kills several larger baleen whales for ³scientific purposes² and after taking measurements and tissue samples, sell the meat as well. The United States allows Eskimos in Alaska to kill 3-4 bowhead whales a year, and Makahs in Washington State to kill a small number of gray whales per year, to sustain their tribes through an exception to the moratorium for aboriginal hunting. ARE ANY WHALES EXTINCT? Many types of whales have become extinct through the process of evolution. Zeuglodonts (pronounced zoo-glow-donts), a group of whales as diverse as todayıs dolphins, became extinct some 30 million years ago. In recent times, while no species has become extinct, certain populations have disappeared. Gray whales disappeared in the North Atlantic Ocean about 300-500 years ago. We do not know if this was due to natural causes or the result of over-hunting. Right whales have not been seen since the early 1900ıs in the Eastern Atlantic, where large numbers were killed from the 1500ıs through the 1800ıs. Current estimates from the same species in the North Pacific today are only 50-150 animals. However, modern whaling has not wiped out any species that we know of. BEHAVIOR: HOW AND WHEN DO WHALES SLEEP? Because whales must think about every breath they take, they can not sleep in the same manner that humans and other mammals do. When periods of resting are observed in humpback whales, the animal lies motionless at the surface of the water, breathing every 2-3 minutes. Through studies on captive cetaceans, it is thought that whales shut down only half of their brain at one time, keeping the other half slightly awake to control respiration. Whales are often observed resting on calm, sunny days, when disturbing waves are at a minimum. What they do at night is still a mystery, but it is believed that resting can take place then as well. DO WHALES ATTACK BOATS? In the early days of whaling, before explosive harpoons killed whales almost instantly, some toothed whales were known to attack the small ³whale² vessels that operated near their mother ship, after being struck by hand-held harpoons. Only two reliable accounts exist of an adult whale ramming and sinking the larger ships. Most, if not all, of these attacks were by sperm whales ( the largest toothed whales). The typical reaction of most baleen whales is to flee, even if struck by harpoons. Modern day attacks are practically unheard of. Occasionally, while whales are engaged in active play with a boat, they have been known to gently nudge the boat with their head or rub their back on the hull, seemingly as a form of interaction with the vessel itself. This has never been known to damage a boat in any way, however, sometimes while feeding, whales have been known to accidentally damage boats that drift in their way. WHY DO WHALES BEACH THEMSELVES? We have all heard about whales that have washed ashore, either alive or dead, and become ³media events.² There appear to be several reasons why whales beach themselves, and it varies based on the particular stranding. The more solitary nature of baleen whales usually leads to single animals washing ashore, usually as carcasses. The large groups of toothed whales and dolphins that strand are probably an extension of the social nature of those species, which live in larger coordinated groups. Among the possible causes of group strandings are parasites affecting navigation, effects of offshore weather patterns, sick individuals leading a group ashore, and many more. One theory favored recently indicates that whales navigate using the magnetic field of the earth. In areas where the magnetic flux is unpredictable, many strandings occur (such as Wellfleet, MA on Cape Cod). Finally, many of the group strandings are of species not normally found near coastlines. Hence it is more common to have group strandings of pilot whales, animals rarely found inside the continental shelf. Mass strandings of Atlantic white-sided dolphins, a common species in Massachusetts waters, are rare, although they have been recorded. WHY DO WHALES BREACH (JUMP)? There are several contexts in which breaching (leaping headfirst out of the water) is observed. It is observed much more frequently in young animals than in older ones, and may serve as a play behavior for young whales that do not have the reproductive burdens and food requirements of adults. Breaching also tends to be observed more often in rough seas and it has been theorized that whales are trying to bring their heads further out of the water to take a clear breath, away from crashing waves. Breaching has also been observed in many social contexts. It is often recorded when whales are forming or splitting from social associations with other whales, and may be conveying some form of important information. It is also frequently observed on the breeding grounds, when males are in competition for access to reproductive females. DO ALL WHALES 'SING'? WHY DO THEY SING? All whales and dolphins have been recorded making sounds, but few have been recorded ³singing.² In order to be called a song, a series of sounds must be produced in a predictable and structured pattern- just like one of our songs that has verses and a repeated chorus! Humpback whales create the most famous songs- a haunting, complex, ever-changing song which is produced by males on their breeding grounds. Simpler songs have also been recorded from blue, fin, and bowhead whales. The function of the song may vary from species to species, but in humpback and fin whales, it is suspected to be a male mating call. The function in blue and bowhead whales remains unknown, however, its seasonality suggests a mating function as well. No songs have yet been found in any toothed whales or dolphins. HOW CAN WE HELP? The biggest problems whales face in their future lies in protecting their habitat. In order to do that, everyone can make an impact by avoiding the use of plastics and styrofoam. Both of these substances are often seen floating out at sea, where marine wildlife consume them (plastics often look like jellyfish and other edible prey). Similarly, use of floating helium balloons should be discouraged; often they land at sea after release. Another popular way to actively improve the marine environment in your area is to organize a beach cleanup. Trash on the beach can be hazardous for many marine birds and often ends up in the water where it can negatively effect fish and other wildlife.