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Whales, along with dolphins and porpoises, belong to a group of marine mammals known as cetacean mammals. The name ‘whale’ can be used for any cetacean (including porpoises and dolphins), but is generally used for those that are longer than 10 feet. An exception is the Dwarf Sperm Whale (Kogia simus), which measures 8 ft 10 in. According to the IUCN Red List, 4 species and 18 subspecies are listed as critically endangered, 11 species and 11 subspecies as endangered and 7 species and 9 subspecies as vulnerable. Other species and subspecies are either close to being threatened or there are insufficient data to determine their status.
Characteristics Cetaceans (Cetacea) have similar characteristics:
Another feature that distinguishes cetaceans from fish is the tail. The tail of a fish is vertical, while the tail of a cetacean is horizontal.
The shape of cetaceans corresponds to their natural development. They have a spindle body and the front limbs are transformed into fins. The hind legs are stunted and hidden inside the body (they are not connected to the spine). Cetaceans have a thick layer of subcutaneous fat (up to 1 foot) to maintain body temperature.
Did you know… the Bowhead Whale is known as the mammal with the longest lifespan – more than 200 years?
Whales are the heaviest animals on our planet. Today, the largest representative is the Blue Whale (Balaenoptera musculus), which measures 98 ft and weighs 210 tons. The smallest representative is the Dwarf Sperm Whale (Kogia simus), which measures 8 ft 10 in.
Classification Researchers estimate that cetaceans today include about 86 species in 10 families inhabiting the world's oceans, lakes and rivers. These are divided into two groups, depending on whether they have whalebones - Mysticetes (right, gray or Rorquals) or teeth - Odontocetes (dolphins, porpoises and sperm whales).
Mysticetes They are also known as Baleen Whales. Most noticeable is their size - they are larger than Odontocetes. Their size ranges from the 20 ft and 6600 lb of the Pygmy Right Whale to the 102 ft and 210 tons of the Blue Whale. The fastest of the Baleen Whales is the Fin Whale, which can swim at a speed of 22 mph.
Here, too, there is sexual dimorphism (a visible difference between the sexes) in the fact that females are larger than males. Another distinguishing feature are two breathing openings, which then has the visible consequence that their exhalation forms a V-shaped fountain. This suborder includes 16 species. Unlike odontocetes, mysticetes do not have the ability to echolocate.
Their name comes from the Greek word mystax, which means "mustache". This name reflects the fact that in the upper jaw, instead of teeth, they have two rows of plates, known as whalebones, with which they filter food from the water. Their food consists of, for example, krill or planktonic crustaceans. They have teeth only in the germinal stage. Blue Whales eat about 8 000 lb of krill per day.
Odontocetes They are known as toothed whales and include dolphins, porpoises and all other toothed whales. They are smaller in size than Baleen Whales. Their size ranges from 4.5 ft and 120 lb of the Vaquita to 66 ft and 61 tons of the Sperm Whale. This is also an exception among the otherwise smaller-size odontocetes**.**
As with the whales mentioned above, sexual dimorphism is evident - whether in size or morphology. A distinguishing feature is also one breathing hole. A total of 73 species are described in this suborder. Toothed whales have the ability to echolocate, unlike Baleen Whales. Active hunters, such as seals, who feed on fish, octopuses and marine mammals, are equipped with teeth. Their speed also helps them to hunt, with speeds of up to 23 mph in some species.
Did you know… the closest relatives of whales are hippos?
Evolution Whales are descendants of terrestrial mammals and thus belong to the class of even-toed ungulates. Thanks to this, even today their closest relative is the Hippopotamus. The first cetaceans appeared in the water about 50 million years ago, although they still had legs at that time. About 34 million years ago, the species split into odontocetes and mysticetes.
Due to the evolution of terrestrial mammals, the whale must regularly rise above the surface to inhale air. However, some species can last up to 90 minutes under water. For example, the lungs of Humpback Whales hold about 1 500 gallons of air.
Whale Senses Cetaceans probably have good eyesight, both below and above the water, due to their eyes, which are small and located on the sides of the head. Not every species has binocular vision like cetaceans, but some have a "sharp beak" – such as dolphins. For example, Blue Whales can't really see ahead or behind them. The eyes are protected by oily tears against the sea salt. It is assumed that their eyes are not sensitive to the entire color spectrum.
Cetaceans have such good hearing that they can hear sounds many miles away, thanks to their well-developed inner ears. The outer ears are small and without auricles.
Touch is well-developed, as evidenced by the large number of tactile bodies in the skin. The whale is able to evaluate, for example, the movement of the surrounding water when it is not moving, but also changes in the pressure of the water flowing around it during its own movement.
Smell is one of the senses that has practically disappeared in toothed whales. The Bowhead Whale (Balaena mysticetus), on the other hand, has a vomeronasal organ (or Jacobson's organ) that allows it to smell krill.
Taste is associated with smell. Some toothed whales choose between different species of fish, which suggests certain taste preferences. This sense may also be related to Jacobson's organ.
Echolocation Cetaceans use sound for orientation, similarly to bats. They emit a sound which bounces off objects and returns to them. Some species can transmit sounds with frequencies from 16 Hz (infrasound) up to 280 kHz (ultrasound) (humans usually hear sounds at the maximum of 20 Hz to 20 kHz). From this reflected sound, cetaceans recognize the size, shape, movement and distance of the object. This ability is called hydrolocation or sonar. Whales can thus hunt even in complete darkness at great depths.
Did you know... Gray Whales are the furthest migrating mammals? They travel back and forth annually a distance of 10 000 miles.
Magnetic Sensitivity Scientists believe that whales, as well as other animals that migrate, have a sense of the Earth's magnetic field. This helps them to determine the correct direction in which to move. Researchers know that a substance called biomagnetite helps birds to migrate long distances. Biomagnetite has also been found in cetaceans. It is also supposed to help them with orientation, but the study is not yet complete.
Diving Cetaceans are very good "divers". During a deep dive, they reduce their oxygen consumption by reducing heart rate and blood circulation. Rorquals can sink for up to 40 minutes, Sperm Whales between 60 and 90 minutes and the Bottlenose Whale for more than two hours. Diving depths are on average about 330 ft. Sperm Whales dive to a depth of about 6 561 ft. The record holder is the Beaked Whale with a recorded dive to a depth of 9 816 ft.
Intelligence Whales are known to learn, collaborate, plan and mourn. The neocortex of many species of whales contains elongated spindle neurons. Prior to 2007, these were known only in hominids. In humans, these cells are involved in social behavior, emotions, judgment, and the theory of the mind. Spindle neurons in whales are found in areas of the brain the same as in humans, so they are thought to perform a similar function.
Researchers have tried to estimate the number of whales killed by industrial hunting in the last century (1900-1999). They came to an incredible number - almost 3 million cetaceans were killed, which may be the largest killing of any animal (in terms of biomass) in human history. According to records, the numbers killed were 276 442 in the North Atlantic, 563 696 in the North Pacific and 2 053 956 in the Southern Hemisphere.
Whaling Although whaling in Japan was banned in 1986, Norway and Iceland have since killed nearly 40 000 large whales. In various countries, more than 100 000 dolphins, small whales and porpoises are killed each year, for example, under the pretext of scientific research.
Bycatch Cetaceans (whales, dolphins and porpoises) become collateral victims by entanglement in fishing nets and fishing lines. For example, dolphins are caught in tuna nets. But because they don't have gills, they can drown if they get stuck in nets underwater. It is estimated that 300 000 whales and dolphins are killed each year as a result of by-catches in fishing.
Climate Change Climate change is a major threat to whales, dolphins and porpoises. The warming of our planet contributes to the loss of the natural environment of cetaceans. It affects the composition of food and its diversity and increases competition. It also affects the timing of migrations, as well as the ability to reproduce.
Collisions with Ships Due to increasing sea traffic, large-scale vessel collisions with whales are becoming more frequent.
Oil Pollution Oil spills are a huge threat to marine life in general, but to cetaceans in particular. They do not have gills to breathe underwater. Cetaceans do not avoid areas affected by oil, because they have almost no sense of smell and are unable to detect oil vapors in the air.
Food Loss and Habitat Degradation Due to their size, cetaceans quickly feel a scarcity of food. This decline can be caused by overfishing, climate change, increased underwater noise or pollution. The result is always the same – less food.
Noise Shipping noise, seismic reconnaissance and military sonars contribute to underwater noise. These unnatural sounds can adversely affect the ability of cetaceans (whales, dolphins and porpoises) to forage or orient themselves in an underwater environment.
What can be done, which initiatives can be supported to help whales and marine life?
Stop Whaling Commercial whaling has been banned since 1986, but there are many loopholes whereby individual countries can continue hunting whales. A total ban on whaling needs to be enforced.
Thwart Climate Change Climate change is knowingly or unknowingly affecting everyone on this planet. It is necessary to change the way we treat Nature and to try to speed up the correction by reducing CO2 in the atmosphere.
Restrict Naval Transport Due to the growing need to transport cargo over long distances, more ships are moving across oceans. There is a need to restrict transport and coordinate shipping routes to avoid whale migration routes.
Reduce Pollution An increasing amount of garbage is entering the oceans and this trend needs to be stopped. There is a need for tougher waste management policies in all countries and for active support for ocean cleaning projects.
Stop Seismic Surveys Seismic surveys are used to search for oil and gas deposits under the ocean floor. This causes damage to the sensitive hearing of cetaceans. It is necessary to reduce oil production and focus on more sustainable energy sources.
Limit Sonar Tests Some cetaceans rely on their sonar orientation system. However, the powerful sonars used by the military, for example, contribute to the disorientation of cetaceans and the more frequent possibilities of them getting stuck in the shallows. This testing needs to be stopped.
How YOU can help: Everyone can get involved
Pay attention to what you eat Fishing plays an important role in the global economy and feeds more than 700 million people. However, by-catch kills more than 300 000 marine mammals each year. Buy food obtained from sustainable sources.
Do not eat whale meat Since the introduction of the international ban on commercial whaling in 1986, more than 50 000 whales have been killed. This is only due to the loopholes that made this hunt possible. If you participate in whale-watching tours, for example to Greenland, they often offer whale meat on cruise ships or in local restaurants.
Dispose of waste responsibly According to the UN, 8 million pieces of waste go into the ocean every day - this corresponds to 6.4 million tons of waste every year. Cetaceans can die if they swallow or get entangled in this waste.
**Spread awareness ** The voice of the individual might not be heard, but the more people coming to the aid of these colossi of the sea, the more awareness will be raised. Many people are unaware of the problems cetaceans face.
Support non-profit organizations with your time or money Any support will help. Financial or one in which you put in all your own efforts. Choose the organization closest to you and help it to meet its protection goals.