Cetaceans (whales and dolphins) emerged 50 million years ago. Believe it or not, they have a common origin with the hippopotamus (!), not with the land predators.
Currently, there are 15 species of baleen whales and 74 toothed whales (out of which 42 are dolphins).
The largest whale (and animal that has ever existed) is the blue whale: it can reach 33 m (100 ft) in length and 181 tons, but it normally reaches 27-28 m (81-84 ft) in length and 150 tons (of which 50 tons are blubber (!), as the fatty layer can have a width of 30-40 cm (24-32 inch)).
The smallest baleen whale is the Pygmy Right Whale, 6 m (20 ft) long and 3 tons in weight.
The largest toothed whale is the sperm whale, whose male can be 18 m (60 ft) long and 50 tons heavy.
The blubber is not only a food reserve; it also serves especially for thermo-insulating in the cold waters where whales live.
A 60-70 tons whale delivers 20-25 tons of meat, 15-20 tons of blubber, while the skeleton weighs up to 15 tons.
The heart of an average baleen whale weighs 700 kg (1,750 pounds), the tongue about 3 tons, the liver one ton, and the 3 m (9 ft) long stomach about 500 kg (1,250 pounds), necessitating 1,200 kg (3,000 pounds) to be filled! The gut can be 250 m (833 ft) long and a blue whale eats 5 tons of food daily!
The brain of a blue whale weighs 5 kg (12.5 pounds) while that of the sperm whale 7 kg (17.5 kg), being the largest brain in nature.
The whale's eyes are very small: a blue whale has the eyes no larger than a small plate.
The lung capacity of a whale at each inspiration can be of 5,000 air liters.
They usually breathe at every 15 minutes but they can hold their breath up to over an hour in the case of the sperm whale. The blue whale's exhaling blow can be 12 m (36 ft) tall!
Sperm whales are known to dive at over 1,200 m (3,600 ft) depths while hunting and Cuvier's beaked whale (beak whales are a type of toothed whale) holds the record for diving amongst any marine mammal: 1,900 m (6,330 ft) for one hour and 25 minutes.
At those depths, water pressure is about 190 atmospheres!
In baleen whales, from the roof of the mouth hang down on both sides about 300-400 keratin fringed plates called "baleens", which can be up to 3.5 m (11 ft) long and weigh in their totality 180 kg (450 pounds). They work like a sieve: the whale sucks at once one ton of seawater: the water is expelled though the baleens' stitches while the food items (crustaceans, fish, mollusks), being too large, are retained by the baleens. Despite their huge size, the pharynx of the baleen whale is so narrow that they can not swallow prey larger than a herring.
After a 10-12 months gestation, whales give birth to just one calf, which suckles for 7-12 months. The lactating female produces 200-570 liters of extremely fatty milk: 200-430 g of fats per liter (for comparison, cow milk contains 40 g of fats per liter).
Usually, the offspring measures at birth about a quarter of the mother's length (in blue whale about 6-8 m (2-2.6 ft) and 2.5 tons). The calf of the blue whale has the fastest growth rhythm in the animal world: over 100 kg (250 pounds) daily, 4.5 kg (11 pounds) per hour, one ton at each 9 days! In 3 years, when it reaches sexual maturity, the blue whale already has 15 m (50 ft) in length.
Another mating record: the blue whale possesses the largest penis in the world: 2.4 m (8 ft) long!
Bowhead whales 130 years old have been hunted and big whales are estimated to have a longevity up to 200 years (which, under the pressure of hunting, it is impossible to reach).
Anyhow, whales are the most long-lived warm-blooded animals, overcome only by some reptiles (giant turtles).
Male sperm whales reach their full size at 50 years!
All baleen whales make long migrations (up to 25,000 km or 16,000 mi annually): they breed and give birth in subtropical-tropical waters and feed in cold waters.
Blue whales and other related species (like Sei whale) can reach speeds of 50 km/h (30 mph) over short bursts but the traveling speed is 20 km/h (12 mph) but while feeding can slow down to 5 km/h (3 mph).
The so-called killer whales can reach 9.5 m (32 ft) in length, 6 tons and possess a mouth adorned with 50 dagger-like teeth.
They are greedy and ferocious predators which attack from penguins to seals, dolphins and baleen whales (included the huge blue whale) but, despite their name, they are not whales but oversized dolphins!
Whales are famous for their singing, perhaps the most famous for that being the blue and humpback whales. Their song can have different reasons: getting a mate, social interaction, alarm, keeping inter-individual distance, feeding, prey location and so on.
Scientists have discovered that each whale population has its own "language" which is understood only by the members of the same population.
The blue whale's song can be between 155 and 188 decibels, making this beast the loudest animal in the world (by comparison, a pneumatic drill is about 100 dB). However, whales sing at frequencies, between 10 and 40 Hz, and all that is under 20 Hz represents infrasounds which people can not hear. Infrasounds have the property of traveling further than audible sounds, so whales can communicate at distances of 80 km (50 mi).
The song of the whales can last from 10 seconds to 2 minutes.
An amazing whale behavior is breaching (lunging) when they leap out of water. Humpback, right and sperm whales regularly do it (other whales display this behavior less) and it is believed to have a role in communication. The act of leaping generates more power than any other act performed by a non-human animal.
Some toothed whales, like the sperm whale, are famous for their mass strandings.
In the most spectacular event, occurred on a New Zealand shore, 46 female and 13 male sperm whales died.
For many years is was thought that whales committed suicide, which would imply consciousness. Other theories state for poisoning, contamination, parasites, stranded individuals followed by the whole group, impairments in their echolocation (due to bad weather or sea bottom geology) and so on.
Today, the most accepted theory is that these strandings have something to do with the Earth's electromagnetism. Cetaceans are believed to use the Earth's electromagnetism during their long journeys and the strandings would occur where perturbations in the Earth's geomagnetic field exist.
Orca may be the whales' only natural enemy, but only people brought whales to extinction.
That's why, since 1986, an international ban on whaling has been ratified, but two of the so-called most civilized nations, Japan and Norway, did not sign it and keep on whaling (even if Japan under the mask of a so-called scientific program).
From a whale what can be used is the oil (employed for lamp illuminating, or making candles, soap, margarine), meat (especially appreciated by the Japanese and Koreans), skin (for handbags, bicycle saddles), baleens (once used for making corsets and umbrellas), liver (for vitamin A and D rich oil liver), tendons (for racket strings or surgery threads), bones, blood (for fertilizers).
Ambergris, a digestive product of the sperm whale, was employed as fixative in perfume industry.
Between 1835-1872, the total number of whales hunted worldwide was 300,000.
The invention of the trans- harpoon cannon in 1868 triggered the massacre. The new harpoon was empowered by fire power and was carrying a grenade exploding when hitting the animal.
Now, the whalers can target fast moving whales, like the blue whale and its relatives (called rorquals). Till then, the main targets had been the slower bowhead whales, right whales, gray whales and sperm whales.
Between 1930-1931, 28,325 blue whales were killed, betwen 1964-1965 only 20 and from 1965 to 1966 just 4! In 1950, 55,795 whales of different species were hunted worldwide, in 1975 - 37,000; and in 1981 - just 15,000.
The whale populations are recovering now, but the process is extremely slow, and the activity of the Japan whaling fleet does no good whatsoever. In the '30s about 20,000 blue whales were killed annually, now the recuperating population is of about 5,000.