Life on Earth has evolved over tens of millions, or even hundreds of millions of years, so some animals may have lived on land long ago and later evolved into aquatic animals. Some animals first lived in trees, and later evolved into terrestrial animals that could not climb trees. Whales were thought to be fish for a long time, but scientists have found that whales are mammals that breathe through their lungs, not fish. Who are the ancestors of whales, and how whales evolved, let's explore the evolutionary history of whales.
According to the study of taxonomy and molecular biology, pigs, whales, and hippos belong to a large family and have a common ancestor, that is, the order of even-hoofed animals represented by ancient even-hoofed beasts. Between 60 and 50 million years ago, two evolutionary branches appeared in the ancient cloister, that is, the ancestors of pigs (pig-shaped suborder) and the ancestors of whales (Indochosians) diverged. About 40 million years ago, the ancestors of pigs evolved giant pigs and wild boars, respectively, about 11,000 years ago, wild boars were first domesticated by Middle Eastern farmers; about 50 million years ago, the ancestors of whales evolved pakistani whales and embarked on the evolutionary path of whales.
Although hippos are taxonomically suborder Porcine, according to molecular biology studies, hippos are closely related to whales, and about 50 million years ago, hippos shared an ancestor with whales. More than 40 million years ago, hippopotamus ancestors, the carboniferous and whales, diverged and evolved along different trajectories, with whales evolving from Pakistani whales , land walking whales ( Kuchi whales ) – Rhodes whales – dragon king whales; 16 million years ago, carbolites evolved into real hippos.
Ancient hordes
The paleostate is the earliest ungulate, plant-feeding, living 50 million years ago in Europe, Asia and North America, and is the ancestor of the earliest known modern pig. It is 50 cm long and weighs about 20 kg, with 5 fingers on the forelimbs, 4 toes on the hind limbs, and a small hoof shape of the third and fourth fingers/toes, which are mainly used to bear body weight. The ancient ungulate beast lived in the forest, had long legs, was suitable for running, and was probably the fastest animal at that time, and was a very good jumper.
Restoration of the ancient horde
Indohos Beast
Indohyus, meaning "pig of India", is a genus of ungulate beasts along with pigs and hippos. Indochoans lived 50 million years ago in Indian-controlled Kashmir, in the southern foothills of the Himalayas, where mountains were not as tall as they are today, with a warm, humid climate, lush vegetation, and facing the ocean.
The Indohos beast resembles a large rat with a long pointed head and a pair of large eyes on the top of its head and a pair of small ears behind the eyes. The body is thin, about 50 cm long, with a slender tail, slender limbs, and 4 toes on the front and back feet, of which the middle two toes form hooves, and the toes on both sides are very short and do not make contact with the ground. From the perspective of body size alone, Indohos beasts do not look like aquatic animals at all, but studies have proved that they often live in water, the reason is that Indohos beasts are plant-eating animals, timid as rats, usually hiding in the depths of dense forests, in order to escape the predation of terrestrial carnivores, often run to the water to hide, over time, under genetic mutations and natural selection, adapted to aquatic life, through the Pakistani ancient whale - land walk whale - Rhodes whale - dragon king whale, evolved into the current whale, such as toothed cetaceans and baleen whales.
The ear canal of the skull of the Indochos has a structure similar to that of the auditory bubbles, like the existing and extinct cetaceans, indicating that the Indohos is more closely related to cetaceans, and it is likely to be the ancient ancestor of cetaceans. But some paleontologists remain skeptical.
Ecological restoration map of the Indochos beast
Ancient whales of Pakistan
Pakicetus , also known as Bucky whales. It lives mainly on the shores of shallow seas or large lakes and feeds on fish. The earliest ancient Pakistani whales, shaped like wolves, had a long conical head, landed on all fours, had a slender tail, and were hairy all over their bodies. The ancient Whale of Pakistan has well-developed hind limbs and can live in the water and on land. They are transitional between terrestrial mammals and modern cetaceans.
Fossils of ancient whales in Pakistan
Ecological restoration map of ancient whales in Pakistan
Land-walking whales
Ambulocetus, also known as wandering whales, was an early whale that could both walk and swim. Fossils of land-walking whales show how whales evolved from land-based mammals. Land whales look like crocodiles and are about 3 meters long. Its hind limbs are more suitable for swimming, and may swing their backs like otters and whales to swim. Land whales also lurk like crocodiles in shallow waters to hunt. Chemical analysis of its teeth revealed that land-walking whales had access to freshwater and marine areas. Land whales do not have external ears, but instead move their heads close to the ground to feel the vibrations, thereby tracking their prey.
Land-walking whales are preying
Whale
Kutchicetus, also known as Kaqu whales, meaning "small whales", lived in the early Eocene 46 million years ago. It is small, similar to an otter, with a body length of about 1.7 meters. whales are capable of walking and swimming and are transitional creatures in the evolution of whales from land mammals.
Restoration of the Cucci whale
Rhodes Whale
Rodhocetus, a genus of the cetacean cetacean suborder Protoceraceae, lived 47 million years ago as a semi-aquatic animal and is a transitional species of cetaceans from land to the ocean. Its pelvic bone is fused with the spine and hind limbs, and has differentiated teeth, the hind limbs are large and web-like, like oars, and the tail is strong, like a rudder, which obviously has the characteristics of a land mammal.
Restoration of the Rhodes whale
Dragon King Whale
Basilosaurus, meaning "emperor lizard", also known as the toothed whale, is an extinct ancient marine mammal, a primitive cetacean, the ancestor of modern whales, living 45 million to 34 million years ago. Fossils are found in places like the United States, Egypt, and Pakistan. The Dragon King whale is 18 to 21 meters long, slender, and short hind limbs, which can prove that modern whales evolved from terrestrial mammals. Dragon King whales have short, sharp teeth, are carnivores, and often use fish,
It feeds on sharks, squid, turtles and other marine mammals.
Restoration of the Dragon King Whale and its cubs
Live cetaceans
Living cetaceans are mainly divided into two species: toothed whales and baleen whales. Odontoceti is a large class of whales, with 72 species. The most distinctive feature of toothed whales is that they have teeth, which are conical in shape and range from 1 to dozens of teeth. Toothed whales have an external nostril and can only spew out a column of water when breathing. The skull is asymmetrical to the left and right. Flippers with 5 toes, large sternum, no collarbone, no cecum, and are obviously carnivorous. Toothed whales vary greatly in size, with the smallest being about 1 meter and the largest about 20 meters, and generally weighing 9 tons. Toothed whales feed mainly on fish, squid, and some can also prey on seabirds, seals, sea beasts, and other large animals such as cetaceans. Common toothed whales include killer whales, pseudo-killer whales, sperm whales, beetleback whales, baiji dolphins, dolphins and so on.
Balaenoptera is a general term for baleen whales, including blue whales, fin whales, humpback whales, bald whales, gray whales, etc., and there are 15 species of baleen whales living there.
Baleen whales are 15 to 20 m long , with slender bodies , black back , white abdomen , grey under the fins and caudal fins , and sickle-shaped dorsal fins that slope backwards. The whisker plates on each side are black, about 300 to 400 pieces, so they are called "blackboard baleen whales". The column of water that the baleen whale spews out when it exhales is high, thin and vertical.
The teeth of baleen whales resemble huge hairs, like most of the hairs on the face. Their "fur teeth" are capable of catching prey. Baleen whales feed mainly on small crustaceans such as krill, and some baleen whales also eat small group migratory fish, as well as benthic fish and shellfish. Different baleen whale recipes are also different. For example, blue whales feed only on krill, and Brucell's whales feed mainly on small fish.
Schematic diagram of the evolutionary history of whales
Combing the evolutionary history of whales is not very knowledgeable, the above picture helps you sort out the evolution of whales, so whales, hippos and pigs, these three seemingly completely incompatible creatures, it turned out to be a family a long time ago!
The above interesting popular science trivia comes from
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