Whales

All of us at least once we have read or have read the story of Pinocchio , the wooden puppet of Collodi's story , which is eaten by a whale , as did the unusual , not so much for the puppet who came to life , but what concerns what a whale can ingest . By now everyone knows that these whales feed on krill, very small animals that are captured through the baleen plates , which filter the water literally . With this blast from the past want to talk about whales, or rather of the order Cetacea , the two sub orders, Mysticeti and Odontoceti . In this post I dedicate myself to Mysticeti , what we all know as whales, but we take a step back , as we are talking about is of aquatic animals , but we must not forget that they are mammals.The history of evolution has taught us that life originated about 360 million years ago, in the Devonian , in an aquatic environment , and the earliest forms of fish evolved more slowly colonized terrestrial environments , thanks to their ability to capture the ' oxygen in the atmosphere. The terrestrial vertebrates colonized the land , and we are talking of the great dinosaurs, extinct, to one of the theories in vogue , because of a meteorite. After this catastrophic event survived only small rodents, with great adaptability, which gave birth to the largest group of mammals . One of them slowly " came " back to the aquatic environment . This led them to have more morphological changes in order to live in an aquatic environment , we are talking about Mesonychidae , animals like dogs , who were still adapted to the terrestrial environment . From this family we remember the kind of Mesonyx , which gave rise to an evolutionary line that led to Hippos and cows. About 50 million years ago developed the first organisms in the order of Archoceti , primitive cetaceans , which had significantly lower legs , while the front legs are modified into flippers , more suited to swimming, the compression of the skull. Since these forms of extinct have evolved Odontocetes ( eg dolphins ) and Baleen ( eg whales ) , which differ by the presence of the teeth in the first , and the nose, as in the second there are two breathers .
With Misticei mean those animals are commonly known as whale ch . Aristotle was the first to understand that they were mammals, many remember him now because they are marine mammals ! To date, we find two families , the first ones whales ( Balinopteridae ) , large animals , the greatest that ever lived on earth, so much so that a three year old child could walk into a his aorta , have a relatively reduced , in fact only go up to 150 tons , a dorsal fin not very big. Include the blue whale 

(Balenoptera musculus ) , minke whales 

(Balenoptera acutorostara ) the smallest , the humpback whale ( Megaptera Maegaptera ), the largest , the latter also famous because often it is found in the presence of bumps along the body , which limestone formations are made ​​by the parasites, the Barnacle . The humpback whale limbs are longer than the entire animal kingdom , in fact, their dorsal fins can reach a length of 5 meters. The second family is that of balenidi ( Balaenidae ) , small animals , aged between 12 and 18 meters , with more stubby shape , a maximum weight of 100 tons. Here we find the right whales ( Eubalaena glacialis and Eubalaena australis) , who live in the ' Atlantic Ocean and Pacific Ocean . Corneas have calluses on his head, too, are parasitized by parasites , crustaceans commonly called the " whale lice " . A characteristic of these the splendid animals is their ability to take advantage of the wind on the " swimming sailing " using their large tail as a sail. The Greenland whale ( Balaena mysticetus ) , which has the longest baleen of the whole family. Other members are the gray whale ( Eschricthius robustus ) , the Caperea ( Caperea marginata ) .