Introduction
The blue whale is the largest living animal on Earth. This magnificent marine mammal is not only immense but also possesses astonishing physiological and behavioural characteristics. This blog article will briefly present the blue whale's various features, habits, and conservation status.
Size and Appearance
The blue whale is gigantic, reaching up to 30 meters in length and weighing up to 200 tonnes. It has long and slender bodies, with skin colour ranging from light blue to blue-gray, sometimes with white spots. The dorsal fin is particularly small, measuring less than 1.5% of the body length, and the pectoral fins are about 4 meters long. The tail is broad and flat.
The body of the blue whale is so immense that just one of its tongues can weigh 2000 kilograms, its skull 3000 kilograms, its liver 1000 kilograms, and its heart 500 kilograms. The volume of its blood reaches 8000 kilograms, and the testes of a male weigh 45 kilograms. If its intestines were laid out straight, they would measure between 200 and 300 meters in length. Its blood vessels are so large they can contain a small child, and the walls of its organs can be more than 60 centimetres thick. A male’s penis can reach 3 meters in length. Their strength is also prodigious, with a 1500 to 1700 horsepower power output. (Source: Blue Whale: The Largest Animal On The Line Of Extinction Hubpages)
Feeding Habits
Blue whales primarily feed on krill. Each day, they can consume several tonnes of krill, using their immense filtration system composed of baleen plates to capture these tiny crustaceans. They open their mouths wide, then close them, filtering the krill from the water through their baleen plates.
Sounds and Communication
The sounds of blue whales are among the most powerful on the planet, reaching up to 188 decibels and travelling hundreds of kilometres underwater. If one blue whale emits a sound underwater, another blue whale can hear it up to 200 kilometres away. This sound propagation capability helps blue whales find each other in the vast ocean, navigate, and search for food. Imagine these gigantic creatures communicating with such powerful sounds in the depths of the sea—isn't it fascinating?
Life Habits
Blue whales are generally solitary, but they can be seen in groups in food-rich areas. Their swimming speed is very fast, reaching up to 50 kilometres per hour. To reproduce, they migrate long distances from cold polar waters to warm tropical waters.
Reproduction and Calves
The breeding season for blue whales generally occurs in winter. Blue whales reproduce in winter, with females giving birth approximately every two years. Gestation lasts between 10 and 12 months, with each calving resulting in a single calf. The calf weighs about 2.5 tonnes and measures around 7 meters at birth. To prevent the calf from suffocating, the female pushes it to the surface for its first breath of air. Afterward, the calf can breathe on its own. The female has two mammary glands on either side of the genital opening. During nursing, she swims at the surface while the calf follows closely underneath. As the calf cannot latch onto the nipple with its lips, the female expels the milk directly into the calf's mouth by contracting her muscles. This milk is extremely nutritious, with a fat content ten times higher than cow's milk. The calf can consume more than 1000 kilograms of milk daily, allowing it to grow rapidly. It can reach 15 meters in length in eight months and weigh 23 tonnes. By 2 to 3 years, it measures more than 20 meters. Blue whales reach sexual maturity around 8 to 10 years and have a lifespan of over 50 years, sometimes living up to 90 or 100 years. (Source: Blue whale winter swim: Scientists track and reveal the secrets of the world's largest animal)
Geographical Distribution
Blue whales are present in the waters of many countries, including Angola, Argentina, Australia, the Bahamas, Bangladesh, Benin, Bermuda, Brazil, Cameroon, Canada, Cape Verde, Chile, China, the Cocos Islands, Colombia, Comoros, the Cook Islands, Costa Rica, Ivory Coast, Djibouti, Ecuador, El Salvador, Equatorial Guinea, Eritrea, the Falkland Islands (Malvinas), the Faroe Islands, Gabon, Ghana, Gibraltar, Greece, Greenland, Grenada, Guatemala, Iceland, India, Indonesia, the Islamic Republic of Iran, Iraq, Ireland, Japan, Kenya, Madagascar, Malaysia, the Maldives, the Marshall Islands, Mauritania, Mauritius, Mexico, Morocco, Mozambique, Myanmar, Namibia, New Caledonia, New Zealand, Nicaragua, Nigeria, the Northern Mariana Islands, Norway, Oman, Pakistan, Palau, Panama, Peru, the Philippines, Pitcairn, Portugal, Réunion, the Russian Federation, Saint Helena, Ascension and Tristan da Cunha, Saint Pierre and Miquelon, São Tomé and Príncipe, Senegal, Seychelles, Somalia, South Africa, South Georgia and the South Sandwich Islands, Spain, Sri Lanka, Tanzania, Thailand, Timor-Leste, Togo, the United Kingdom, the United States, Uruguay, Western Sahara, and Yemen. (Citation: Balaenoptera musculus The IUCN Red List)
Current Protection Status
Due to excessive hunting in the past, the population of blue whales has significantly decreased, and they are now classified as an endangered species. The international community has implemented numerous protection measures, such as hunting bans and habitat preservation. Despite this, blue whales continue to face threats like environmental pollution and climate change.
Conclusion
Blue whales are majestic giants of the oceans, reminding us of the grandeur and fragility of nature. Through this blog article, I hope you will learn more about blue whales and support efforts to protect these incredible creatures.
Whale Watching in 2024
In September this year, I had the opportunity to observe blue whales, humpback whales, fin whales, and belugas in the St. Lawrence Estuary in Quebec. Researchers specializing in blue whales revealed that they had observed 12 blue whales in just two weeks in the St. Lawrence estuary, which is incredible. In September alone, many blue whales came to feed in the St. Lawrence estuary, reaching as far as Tadoussac Bay. These gigantic marine mammals can indeed come to feed in our St. Lawrence River, which is impressive.
Twice in September, I took a Zodiac down the St. Lawrence River. The first time, after 8 hours, we did not see any blue whales, but only groups of belugas with their magnificent white silhouettes. On my second outing, the weather was perfect, with no breeze, and the afternoon light cast a soft glow on the water, making the sea surface very attractive. Suddenly, a huge blow astonished me; an immense blue whale appeared near us, adding a blue touch to the enchanting scene. It was the first time I had seen a blue whale, and it is said that only 16% of blue whales show their tail flukes when diving. I was lucky enough to photograph this magnificent tail fluke on my first encounter. I couldn't find words to express my emotion at that moment—you can imagine. I took some photos of blue whales, fin whales, humpback whales, and belugas in the St. Lawrence estuary in September. I want to share this with you. Thank you so much for visiting my page website.
Fin whale (Balaenoptera physalus)
Suborder: Mysticeti
Size and Appearance
The fin whale is the second largest marine animal on the planet, measuring 19 to 26 meters (62 to 86 feet) long and weighing about 50 to 70 tons (110 to 150 pounds). Its body is long and slender, mostly gray-brown in colour, with a lighter belly.
Diet
It feeds mainly on small fish, krill, and plankton, filtering through its baleen.
Distribution
The fin whale is widely distributed throughout the world's oceans, especially in temperate and polar waters.
Humpback Whale (Megaptera novaeangliae)
Suborder: Mysticeti
Size and Appearance
The humpback whale is a large cetacean with particularly long pectoral fins, representing about a third of its body length. It measures between 15 and 18 meters long and can weigh up to 60 tons. Its caudal fin has wavy edges and often emerges from the water when it dives. Each caudal fin pattern is unique, like a human fingerprint, which helps scientists identify and study individuals.
Diet
The humpback whale feeds mainly on krill and small fish. In some areas, it uses a unique hunting method called "bubble netting" to gather its prey, then opens its mouth wide to feed.
Distribution
Humpback whales are found in the world's oceans, from tropical to polar regions.
Summer: They migrate to food-rich waters in high latitudes such as Alaska, Antarctica, Iceland, and Norway.
Winter: They migrate to warm tropical waters such as the Caribbean, Hawaii, and
Baja California in Mexico to breed and raise their young.
Beluga (Delphinapterus leucas)
Suborder: Odontoceti
Appearance
Adult belugas are completely white, while young are gray. They measure between 4 and 6 meters long and weigh up to 1.5 tons. They do not have a dorsal fin.
Diet
They feed mainly on fish, squid and crustaceans.
Distribution
Belugas are mainly distributed in the Arctic and subarctic regions, such as Canada, Russia, Greenland and Alaska. In the summer, belugas migrate to estuaries and shallow bays to feed. During this season, they can be seen in the Tadoussac Fjord in Quebec, where they reproduce.
Special feature
Belugas are famous for their unique white appearance and vocalizations. They are often nicknamed "the canaries of the sea."
Finally, whales play an important role in the marine ecosystem by helping to sequester CO2. When they feed and defecate, they feed phytoplankton, which absorbs CO2 through photosynthesis. Additionally, when a whale dies and sinks to the bottom of the ocean, it takes all the carbon it has accumulated over its lifetime, storing CO2 for centuries.
Quantifying exactly how much CO2 they absorb is complex. However, one study estimates that a giant whale can sequester about 33 tons of CO2 over its lifetime. For comparison, a mature tree can absorb about 22 kg of CO2 per year. This means that over a 100-year period, a tree could capture about 2.2 tons of CO2, much less than a whale can help sequester.
It is fascinating to see how these sea giants contribute to the health of our planet by playing a crucial role in our ecosystem.
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