The Humpback FAQ |
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Family stories Why is the humpback whale called a humpback whale? What special characteristics do humpback whales have? How long do humpback whales live? How large do humpback whales become? How many humpback whales exist? What threats are endangering the humpback whale? Can we find humpback whales in all seas? Why do the humpback whales migrate? Do humpback whales always return to Hawaii? How long are the humpback whales on their journey? Do humpback whales migrate alone or in groups? What kind of social bonds do humpback whales exhibit? What is the difference between the populations of North and South Pacific? Are the populations of North and South Pacific mixing together? How long do the humpback whales stay in Hawaii waters? How can one identify an individual humpback whale? How do humpback whales reproduce? How do humpback whales sing? What is known about their singing? Why do humpback whales sing? What can we learn or use from their singing? How long does a whale's song last? Do humpback whales sing the same song everywhere? How far do the songs travel under water? Why do humpback whales breach? How well can humpback whales see? Can humpback whales see in color? How long can humpback whales dive? What is a spout/blow? Do humpback whales sleep? What do humpback whales feed on? Do humpback whales eat the oceans empty? How do humpback whales hunt it's prey? What are baleen plates? Humpback whales come from the order CETACEA. Cetacea includes whales, dolphins, and porpoise. (There are no porpoise in Hawaii). Cetus is Latin, the original meaning was "large sea animal", and it is used in biological names to mean "whale". Cetaceans are the marine mammals who have fully adapted to aquatic lifestyles. Their forelimbs are modified to flippers, their tiny hind limbs are vestigial , they are not attached to a backbone, and their bodies are fusiform (spindle shaped). The order Cetacea contains 90 known animals, all marine except four species of river dolphins. Cetaceans are nearly hairless (dolphins are born with a mustache, and humpbacks have hair on their heads during their entire lifetime), and are insulated by a layer of blubber. They are noted for their amazing intelligence. The order is divided into two sub-orders. Mysteceti (baleen/mustached) and Odonteceti (toothed animals). Mystecetes have two blowholes and odontocetes have only one. In this family of whales, the humpback whale has five siblings: the Blue -, Fin -, Sei -, Bryde's and Minke whales. The Blue whale is the largest animal that ever lived on our planet: it can grow more than 90 feet long and weigh up to 180 tons. Its heart is as large as a small car! At Whalesong, we concentrate on the largest and most famous cetacean to the waters around Hawaii, the humpback whale: Class: Mammals (Mammalia) Order: Sea mammals (Cetacea)Subordination: Baleen whales (Mysticeti) Family: Rorquals (Balaenopteridae)Kind: Humpback whales (Megaptera novaeangliae) Why is the humpback whale called a humpback whale? The humpback whale probably got its name from early whalers that designated the name based on their observations. When diving, these whales have an area of pronounced blubber in front of the dorsal fin, giving the back a ‘humped' look. This is mentioned in many whaling records. What special characteristics do humpback whales have? Although humpback whales differ from their other family members in many ways, one characteristic that is the same with all six family members is the way the throat grooves, or ventral pleats, are situated. All of the baleen whales have 14 to 35 throat grooves which run from the chin to the navel. The main difference between the humpback and the other whales is that their flippers (pectoral fins) are unusually long - up to approximately 20 feet, which is up to a third of their whole body length. Therefore, they also have the scientific name Megaptera novaeangliae, which means "Great Wings of New England." The reason the flipper is so long is still a mystery, although scientists have learned that the pectoral fins, with the knobs on the leading edge, make for amazing control and turning abilities. More studies are being done on this subject. How long do humpback whales live? Scientists estimate a life expectancy of up to 50 years, maybe even longer. Years ago scientists attempted to age humpbacks by comparing the growth rings within the ear plugs, which proved to be unsuccessful as the whales do not always migrate annually, and usually sink when expired, so obtaining the ear plugs is nearly impossible. A fairly recent study of a relative baleen whale, the bowhead, proved to be more successful. Indigenous Indians of the north are allowed to hunt a few whales annually and scientists were given the eyeballs. Testing the amino acids behind the eye lenses they found several whales to be well over 100 years old and one, in particular, was 179 years of age! How long do humpbacks live? They simply do not know. Further studies have to be done on this. How large do humpback whales become? Humpback whales are born 10-20 feet long and can weigh 1-2 tons at birth. A full grown humpback whale (at the age of 12) could grow up to 45 feet long and weigh up to 40 tons, with the females usually being longer and heavier than the males. Their flukes grow to be nearly 20 feet wide - as long as their pectoral fins are and roughly the length of their heads. Nearly 40% of their weight is muscle! The largest humpback whale recorded was caught and killed in the Caribbean many years ago. She was 88 feet long. How much she weighed was unknown since they are taken apart before hauling on board. Some scientists speculate that humpbacks could theoretically continue to grow as they age. To this day, the largest humpback known is 50' long and weight most likely 50 tons. (They weigh a ton per foot.) Where did all the big ones go? The sad answer is they were probably taken by the whalers. It may take several generations before we have true answers. How many humpback whales exist? The estimations of the current population vary widely: some speak of 5,000-7,000 animals, and others of 12,000-14,000 animals. Even if there were 14,000 animals, that would only be a fraction of the originally estimated population of approximately 115,000 animals. The humpback whale's existence is, therefore, considered endangered. They received full protection by the International Whaling Commission (IWC) in 1963, but are still hunted illegally. Currently there are many efforts being made to save these animals. To date, researchers are feeling very encouraged by the North Pacific population annual increase of about seven percent. Calf mortality still appears to be very low. What threats are endangering the humpback whale? The humpback has two natural threats: the killer whale and the shark. But the most dangerous threat for these creatures is human beings: Commercial whaling: Whales received full protection by the International Whaling Commission (IWC) with a moratorium in the commercial hunting in 1986. Three countries - Japan, Norway and Iceland - have used loopholes in its wording to unilaterally resume hunting of several whale species. One is the so-called "purpose of scientific research". In order to stimulate the local market a recent plan of the Japanese government suggests to offer whale meat in school cafeterias as the storerooms are full of whale meat and blubber. In April 2010 whale meat was found in restaurants in Santa Monica and Seoul, South Korea and scientists identified several different whale species in sashimi including fin whale, sei whale and Antarctic minke whale. All of these are listed with the Convention on International Trade in Endangered Species (CITES), which prohibits the international trade of endangered species. Read the full story Here are some facts, taken from the WWF website: Japan has killed 8.201 minke whales in the Antarctic for "scientific purposes" since the moratorium in 1986. A total of 840 whales were killed by Japan under special permit during the 31 years before the moratorium (1). Japan took a total of 866 whales in 2006/07 season:
The 2005/06 season was the first time Japan had taken fin whales, an endangered species. Iceland: In 2006/07 Iceland took 60 minke whales under special permit for "scientific whaling", up from 39 in the last season (1). However Iceland announced in October 2006 that in addition to the whales caught for scientific research, they would resume commercial whaling and issued quotas for 30 minke whales and 9 fin whales (2). Norway took 545 whales in 2006 season. (1) Info from IWC website Ocean pollution: Analysis of blubber has shown traces of POP's (Persistent Organic Pollutants). A stranded sperm whale at the German coast of the North Sea had to be treated as dangerous waste because the body had been so polluted. These POP's also affect the reproduction of the whales. Mercury levels in marine mammals have reached a record high making the consumption of these animals extremely dangerous. Noise pollution: Increasing noise pollution, in the form of underwater explorations for oil or gas, ships, air guns or newly developed underwater sonar systems, is affecting the navigational abilities of the whales. The "LFAS" (low frequency active sonar) is able to detect quiet vessels and therefore it produces extremely loud sound waves (up to 180 db!). All this could be linked to the increasing number of marine mammal strandings. Marine debris: Lost or dumped equipment from the fishing industry is an increasing danger to the whales. They are not able to see these nylon nets and if they become entangled, they will drown. More and more whales, dolphins, porpoises, sharks and other marine mammals suffer painful deaths from entanglement. Global warming: Global warming has an influence on the whale's food chain. There will be less krill if the ice crust of Antarctica is melting, which means blue whales would have to cover a much greater area to find enough food, leaving less food for the humpbacks. Over-fishing: Several commercially used fish species are vastly over-fished, which means their population is endangered because they don't have enough time to reproduce. It's a disruption to the whale's food supply and, unfortunately, the steps to a sustainable fishing industry (with a fixed catch quota, for example) are taken very hesitantly. There is very good news recently (August, 2008) on krill making a comeback and how this will directly affect our whales. If you want to know more, please click HERE and read all about it. Can we find humpback whales in all seas? Humpback whales exist worldwide - the National Marine Sanctuary has identified 6 different populations. Whalesong concentrates on the population of the North Pacific. The majority of the population (approx. 60%) migrates into the warmer waters around Hawaii during winter time. Approximately 30% migrate to the coast of Mexico or Baja California, and the remaining 10% make the journey to the southern islands off Japan. They are found frequently in proximity to the coast in relatively shallow water. That gives us the possibility of being able to observe the whales well - in Hawaii you can often see the whales from the beach! They are, however, not around Hawaii throughout the entire year. The first whales come to their breeding ground in the warmer waters at the end of October, at which time some give birth to the new generation. According to many researchers, most whales may spend only a few days in the breeding grounds after their arrival, then they make their way back again to their feeding grounds around in the north. The exception would be new mothers who must wait until their little ones are strong enough for the journey, and may stay in Hawaiian waters for 1 ½ to 2 months. Why do the humpback whales migrate? Humpback whales undertake a great journey, about 3500 miles one way. The waters around Hawaii are relatively warm and thus offer ideal conditions to the whales in order to reproduce. Although scientists disagree humpback calves would not survive in colder waters since they are born without a blubber layer, others argue that seals, porpoise and other mammals' young do survive. One argument that does hold merit is the fact that the orca, a strong presence in the colder waters and the one main predator to whales, does not exist in large numbers in the breeding grounds. Warm waters, however, have the disadvantage that there is hardly enough food for the whales there so they must head back to Alaska, since the cooler waters offer a "richly covered table" for the humpback whales there. During the time between the end of October and the beginning of May, the whales are on a "diet" and it is said that a full-grown humpback whale loses several tons of weight during the time it spends around Hawaii. A nursing mother may even lose a third of her weight! Researchers are also aware that not all humpbacks migrate. Humpback whales are seen off Alaska and Canada all year around. Several years ago a new baby was spotted off Prince Rupert with its mother! Do humpback whales always return to Hawaii? We don't know for sure! Some scientists believe that at the beginning of the 19th century the humpback whales wasn't known in Hawaiian waters. However some Hawaiian chants of ancient origin refer to the "kohola lele" (the jumping humpback whale) in Hawaiian waters. It would be the only known case where whales changed their migration routes. Today, about 9000 humpbacks per year can be found in the waters around Hawaii. That is about 60% of the whole humpback population of the North Pacific. The largest concentration is found in Maui County. Here, the water is fairly shallow (less than 1.000 feet) making humpback communication more easily heard. How long are the humpback whales on their journey? With the help of transmitters and satellite monitoring systems, scientists have already been able to determine the duration of their migration. Through observations of individual humpback whales, scientists estimate that they travel a distance of approximately 3500 miles between their breeding and feeding grounds in 30 to 39 days. The National Marine Sanctuary identified an individual humpback via photo-ID in Alaska and in Maui only 28 days later, which means that this particular whale traveled 3500 miles in less than a month! Humpbacks travel at an average speed of approximately 3 to 6 miles per hour, but are able to reach up to 20 mph for a short time. Do humpback whales migrate alone or in groups? Humpbacks usually aren't gregarious animals – they rarely appear in groups or so-called pods. The humpbacks do not all migrate at one time, and not all migrate. Most of the humpbacks head to Hawaii alone or a small collection, and they probably meet with other whales on the way. Scientists tell us that a collection of humpbacks is called a group. They have decided that the word ‘pod' is to be used for structured groupings, such as the families of dolphins, orca, sperm whales, and others. What kind of social bonds do humpback whales exhibit? Our knowledge about the social bonds of the humpbacks is not yet distinctive. We assume that most of the bonds are only short term – the longest and most intense bond being between mother and calf, since they are inseparable for at least a year. There are assumptions of a deeper complexity which deserve study. Males could cooperate, as well as compete, with each other. For example, in their breeding grounds they compete for the best place next to a receptive female. Most of the humpbacks are hunting and feeding on their own, but about 25% get together in pods and cooperate in the foraging, though they may travel alone the rest of the year. What is the difference between the populations of North and South Pacific? The humpbacks of the North Pacific (Alaska, Canada, Hawaii, Japan, Mexico) are usually a little darker on the underside of their flukes, their pectoral fins, bellies, and their throat grooves compared to the population of the South Pacific (Antarctica, Australia, South Pacific Islands). While many of the humpbacks sing head down to Hawaii, it's the opposite in the South Pacific. There may be many other differences as well and both populations are being closely studied. Are the populations of North and South Pacific mixing together? Usually the two populations do not mix together. Since the seasons of the year are opposite in each hemisphere, the humpbacks of the North Pacific are migrating toward Alaska and Canada in May at the same time the humpbacks of the South Pacific are migrating from Antarctica to Australia and the South Pacific Islands. In October, it goes the other way around. But, there is an exception to every rule: One season, researchers in the northern hemisphere noticed a whale with a fluke that was plain white on the underside. They couldn't find the whale in their photo-ID database and sent the photo to researchers in the southern hemisphere. Australia called right away, "Hey, this is our whale!" In old whaling records there are several instances where the whaling vessels followed humpbacks from the southern hemisphere and wound up in the "Sandwich Islands" (Hawaii). How long do the humpback whales stay in Hawaii waters? There are different opinions. Dr. Jim Darling suggests an average stay of just two weeks in Hawaii waters before heading back to Alaska, others think it could be longer, but they all agree that the duration of their stay depends on different circumstances: a recently impregnated female will head back right away (a female had been identified via photo-ID on the way back after just 21 days in Hawaiian waters); a mother who has given birth will stay longer until the calf is strong enough to make the long, dangerous journey. According to Dr. Darling, the longest stay researchers are aware of is 2 months with a mother/calf pair. How can one identify an individual humpback whale? The underside of the tail (called a fluke) has a unique pattern, and is a distinguishing characteristic comparable to a human fingerprint. The fluke could be differently patterned in black, grey, and white, and it may have scars from an orca or a collision with a boat. Flukes are being photographed and researchers have access to a special database in which all the photographs are archived. This is called photo-identification. That gives us the opportunity to gather revealing information about a whale's preferred feeding grounds, migration routes, and behavior within a pod. New research suggests that most orca attacks are done on calves and juveniles, but the scars are lifelong. In the near future, NOAA hopes to have a global database that everyone can access and even add their own fluke photos to it. How do humpback whales reproduce? Sexual maturity After approximately 5 (females) or 7 years (males), and after they have reached a length of approximately 35-40 feet, females as well as males are considered to have reached sexual maturity. Females may mate every 1-3 years after reaching their sexual maturity, according to research. Males will head to breeding grounds to mate, compete, or if you are a young male humpback, just watch and learn. Gestation period After a gestation period of approximately 12 months, female humpbacks give birth to a whopping baby, 10 – 20 feet in length and weighing 1 – 2 tons, depending on the size of the mother. Calves length is approximately the length of mom's head, so small moms, little calves, big moms, enormous young. The North Pacific calves are born in warmer waters around Hawaii, Baja California, and off the Bonin Islands of Japan. According to researchers calves are born positively buoyant, which means immediately after birth they will bob to the surface like a cork. Nursing The mother nurses the calf for anywhere between 6 and 11 months. While feeding, mother and calf are close to the surface so that the calf can easily reach to breathe. The term nurse or suckle is actually not completely correct, since the milk is squirted by the mother into the mouth of her calf. The calf will 'latch' on to the nipple using the tip of the rostrum. Photos of new calves show the skin pigment worn away in the front. Also, according to researchers, the calves have no baleen in the very front of their mouths creating a small gap. If it were not this way, the milk would hit the baleen and the nutrition would be lost. Feeding the calves up to 100-130 gallons of milk, which is very thick, the consistency of yogurt, and 50% fat every day allows the baby to gain about 100 pounds every day. At this rate, researchers have discovered the calves rapidly grow 1 foot per month! Before its first birthday, the "little" humpback whale already eats krill and fish and has doubled in weight and length. The following year, if the mother returns to the breeding grounds, the yearling may follow, but not all do. Off the coast of Canada, many ‘little' ones have been seen and photographed staying and continuing to follow the food to small inland passages. How do humpback whales sing? For a long time, it was believed that whales cannot sing since they do not have functional vocal cords. Researchers believe that the sounds are produced by pushing one air stream in different directions within their respiratory tract, and another study suggests the thorax may be used. In the 1950's, their singing was discovered when the United States Navy experimented with hydrophones. From then on, their singing has been analyzed by scientists, who describe it like this: the whales go to a depth of between 45 & 130 feet and get into a certain position when they sing. They may remain motionless with their head downward, or are sometimes seen traveling, either alone, or with another male and a small percentage are observed traveling with a female and her calf. Kent Noonan, our engineer, made the following experiences: "There was a mother/baby/escort pod traveling toward me while I was out in my kayak with my hydrophone. The mother and baby veered to one side and swam by me underwater. The male swam directly under me only a few feet down and continued singing uninterrupted. I was listening as he approached and it became so loud I thought my ears would burst. I tore the headphones off and could still hear it very loud as he passed under me only about 8 feet down. Another time I saw a large male singing while I recorded nearby. He was slowly swimming in a large circle under a mother and baby. He went in a circle perhaps 100 yards across at a rate of about 15 minutes to go around it, about 50 to 100 feet down. This is the recording I call "Kalama Lullaby" because it seemed he was making a cradle of sound for the mother and baby to feel protected in, while they snuggled on the surface in the sun" What is known about their singing? We can distinguish several kinds of sound, the so-called "social sounds", "communicative sounds between mothers and calves", the "feeding siren" or "call" done in the feeding grounds, and the classic "whalesongs" we are engaged with. With all the studies being done each year, perhaps even more types will be uncovered! social sounds These are short, quick sounds which can hardly be heard (or not heard at all!) under water with the human ear. These sounds can only be picked up with special hydrophones which would have to be close to the whales and pointed directly at them. The social sounds are used to communicate, especially when they travel slowly on the surface or when resting - but not when traveling at higher speeds. The majority of this kind of communication (85%) takes place between mothers and their calves, according to Dr. Marsha Green, but another example may be whales within a group communicating with each other. whalesongs It has been defined that only the humpback whale males are singing. Unlike a pop song with a melody, a whalesong is more like a string of different sounds in different pitches that can sound like humming, snoring, groaning, sighing or chirping. Similar to classical music, a whalesong consists of different themes which develop and build over the years. The whale songs can even be heard from a distance of 100 miles or more. The whales are singing mainly in their breeding grounds or on the way from or to their feeding grounds in cooler waters. Although whale singing has been heard in the feeding grounds up north, other communicative sounds are much more common and are currently being studied. Perhaps we will be able to install a hydrophone in Alaska one day to learn more about that. Why do humpback whales sing? Although it is the best known and most studied large whale, nobody knows exactly why the humpback whale sings. As the songs are performed almost exclusively in the breeding grounds, researchers believe that singing and mating go together. But whether a male is trying to impress a female or get rid of competitors or show his social status still remains a secret. Another theory explains the singing as a kind of sonar to find other whales. A recent study by Dr. Darling and his team shows several hypotheses still being studied. One is females are chased by singing and non-singing males. Another is pairs of males around females take on different roles of blocking and chasing, and yet another is not all male-singer relationships are non-agnostic, that is, in many instances they witnessed highly agnostic reactions. The research team found that with adult male/male interactions that were mediated with song were extremely common in our breeding grounds and that the singing usually stopped with the interaction. They also found most interactions were with an adult male singer being joined by another adult male, and at some times two adult males. Also according to the team, several observations appear to tie in sequential behavioral patterns. Most common, they say, is a lone male singing, occasionally singers are accompanying a mom/calf, and a small percentage was a singing male accompanied by another adult, sex unknown. They feel the song might help in organizing the males and may provide a real time measure of association between the different males and maybe providing a means of mutual assistance in mating. Definitely more studies will need to be done. We look forward to reading the results of future work and will eagerly share it with you. What can we learn or use from their singing? We do understand the importance of communication within the species. It is imperative these animals stay as a protected species, not just for our own studies and observations, but so the future generations can hear, first hand, the amazing voices of the deep. Building up a world-wide monitoring system would make it possible to learn much more about the migration patterns of these giants. We at Whalesong hope to reach more scientists with our website who could use our broadcast for their work and then discuss their experiences with us. How long does a whale's song last? According to the experts, the song generally lasts from 5 to 20 minutes long and has a hierarchically organized sequence of sounds. There are specific sound units that are organized into phrases , and these phrases then are repeated several times as a theme. The song, often five to seven different themes, is often repeated without stopping, says Dr. Jim Darling. Do humpback whales sing the same song everywhere? The unique dynamics of the song changes collectively, which means all the singers within the population sing the same version. The song's rate change may change however, with a complete turnover to a new song varying by area. In Bermuda one study showed a complete turnover in five plus seasons. In Australia, it was two seasons. The songs differ from population to population - the humpback whales of the North Pacific (Hawaii, Mexico, Japan) have a different song than, for example, the humpback whales of the South Pacific (Australia and the Islands of the South Pacific). Is this is a version of different dialects? How far do the songs travel under water? Blue whales could once communicate from pole to pole - that means halfway around the world! But due to increasing noise pollution of the oceans, this is believed now to be nearly impossible. Researchers tell us noise under water travels five times faster than above. Years ago while doing a humpback singing study, researchers working together in Mexico, Japan, and Hawaii, found when the song altered slightly in Hawaii, within several days it also altered in Mexico and Japan to match the Hawaiian singers. What this means has baffled researchers who promise to continue their hard work toward a better understanding of these beautiful and mystifying animals. Why do humpback whales breach? This behavior can be observed by all baleen whales, however the humpback whales are considered to be the acrobats in the family. They screw their body to two thirds or more out of the water, like turning on their own axle. With their powerful fluke they only need a few beats to screw themselves out of the water. One can observe such jumps mainly in the breeding areas, also in the waters of Hawaii! Therefore, it is assumed that this is a breeding behavior. Scientists also suppose this is a way to communicate or to get rid of parasites. No matter why they do it, it is an overwhelming spectacle! How well can humpback whales see? Humpback whales can see well beneath and above the water since the colors change under water. Their brown eyes are perfectly adapted: lachrymal glands produce a fatfilm which protects the eye from saltwater. The lens is elastic and can be adjusted to the different light conditions by muscle power. Humpback whales can see up to 400 feet under clear water. They can also see equally well above the surface. According to research, cetaceans also have a tapetum, giving the eye the ability to reflect light back through the retina increasing the light available. This is especially important in low light conditions, but also important in water where things appear more blurry. Can humpback whales see in color? Although the rod-like and cone-like receptors are present in the eyes, according to researchers, the ability to discern colors in dolphin studies suggests that most likely the cetaceans cannot see in color. The data to explore color vision for baleen whales is greatly lacking. How long can humpback whales dive? Up to 45 minutes, but usually they dive 15-20 minutes depending on what they are doing. If the whales are within a so called "competition group" (several full-grown males are trying to get the best position to the one female in the group), they are travelling with faster speed, fighting and breaching, which costs them a lot of energy. Then they must come up to breathe after only 5-10 minutes. When the whales are avoiding loud vessel engines, researchers have observed them staying down 45 minutes in the same position, coming up at the same spot they went down 45 minutes before. In the feeding grounds of Alaska and Canada, the longest downtime observed was 55 minutes. It is also known they are capable of depths of 600 feet, according to Dr. Adam Pack, who tagged humpbacks in Hawaii last year. This astounded the science community who all asked, "what are they doing down there?" Hopefully we'll have answers soon. What is a spout? If a humpback whale is coming to the surface to breathe after a dive, it exhales air with a speed of more than 300 m/h. The whales are utilizing about 90% of their lung capacity of 2500 gallons - in comparison with humans, which utilize about 15% when breathing normally! Their lungs are very large and when they exhale they force the warm air through a small sinus opening, forcing the air to cool in nano seconds (like air in a compressed can). This shows up as a tall vapor, which can be as high as 15', bushy to heart shaped for a humpback whale. The exhalation is also called spout, or blow. The inhaled amount of oxygen is "stored" in their blood and to 40% in their muscles which enables the whales to go as deeply as 600 feet or more and stay down up to 55 minutes (recorded in the feeding grounds). The whalers years ago knew that every species of whale had their own signature shape of exhalation and could tell from a distance what type of animal was traveling in the area. Do humpback whales sleep? It's not exactly sleep - it is more like doze. Humpbacks are not ‘conscious breathers', which means they have to think of breathing (just like we human beings) under water. Nevertheless, researchers believe they have the ability to switch off half of their brain to relax. The other half of their brain is thinking of breathing, being aware of predators like orcas, or taking care of the baby if it is a mother. What do humpback whales feed on? They feed mainly on 'krill' (or small crustaceans which look like shrimp about 2 inches long) and on small fish such as herring, mackerel, capelin, scad, sand lance, small salmon, and cod. The name krill originates from the Norwegian word "kril" which means "small fry of fish (1907)". In the cold Arctic and Antarctic waters, these krill are found in large close swarms. Humpback whales eat up to a ton of feed per day when they are in cooler waters to build up a thick fat layer, called "blubber". They live on this blubber during the winter months when they stay in warmer waters where less food is available. The blubber layer on a large whale can be up to 18" thick! Do humpback whales eat the oceans empty? That is the argument of the Japanese lobbyists for commercial whaling, who claim that the whales will deplete all the fish stocks, but it is not true! Humpback whales are not able to eat big fish which we humans prefer (like tuna, perch or swordfish) because their throat only has a diameter of only 6-8 inches or the size of a cantaloupe! If a bigger fish came into its mouth, the humpback whale would have to spit it out to avoid chocking. The types of fish the humpback whales eat are not overfished, yet. The greatest danger to the fish supply comes from humans who are about to destroy global food supplies by overfishing. How do humpback whales hunt it's prey? Humpback whales have developed different hunting techniques. Sometimes they simply swim through a large swarm of krill with an open mouth taking in tons of water and krill. In order to be able to take up such masses in the mouth, the throat grooves expand greatly. The water exits the mouth through the baleen plates when the tongue is pressed to the roof of the mouth. On a large whale, the tongue alone can weigh 2 tons! The small crustaceans or fish are caught behind the baleen plates (see also: What are baleen plates?) and then swallowed. A very specific technique of the Humpback whale can be observed: sometimes four to six whales unite in a group, diving down and circling a swarm of krill or fish. While circling and slowly emerging to the surface, the whales discharge air so that a net of bubbles develops. These bubbles force the prey in the center of the circle and what looks like a circle of ascending bubbles emerges, resulting in a spectacular event where several humpback whales with open mouth suddenly appear at one time taking up what they caught in this net of bubbles. What fascinates researchers is the whales can control the bubble sizes. Small bubbles for small prey like krill and larger bubbles for fish! Researchers have also discovered that the feeding groups may be established friends that may feed together every year for a lifetime. Dr. Fred Sharpe discovered also that there appears to be a ‘senior' member who does a "siren call" and is also seen to be the first whale to the surface. More research is being done to try and unlock the secrets of feeding behaviors with humpback whales, the only whale on the planet known to use bubbles in this way. What are baleen plates? Baleen plates are made of keratin and grow down from the upper gum line where teeth used to be. Baleen whales have not been on the planet as long as toothed whales. What caused the division within the family is unknown, but most likely had to do with feeding. Baleen whales take many prey at once, toothed whales eat one at a time. The number and length of the baleen plates differs between different types of whales. Humpback whales have approximately 270-400 of black fringed plates, which grow to be about 2-3 feet long with a large animal. (In a bowhead's mouth they can be up to 7 feet long!). They consist of material similar to human fingernails or hooves of cattle and horses. The baleen plates are arranged in lamella form and serve as a filter for food. The prey gets caught behind the bristly edges when the whale closes its mouth and is swallowed whole. Another interesting fact is different species of baleen whales also have different widths, lengths, and color of baleen. For years scientists have hoped to age baleen whales by counting the growth lines on the baleen (similar to ridges on some fingernails), but this study was abandoned upon the realization that to obtain many expired animals of each species is impossible and knowing that the baleen on the ends wears away, leaves more questions than answers. With newborn humpbacks, their baleen is white to grey, according to researchers, and in the front of their mouths, the baleen is either absent, or only a couple of inches long. By the time the little one is weaned (as early as 6 months), the baleen will have grown down to where it should be. Baleen continually grows throughout the whale's life, the ends becoming worn and frayed, but always present. |
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