We all know the ancestors of whales are small land mammals, after starting to live in the ocean, they went through more than 50 million years of evolution and eventually became a family of marine mammals. have the most diverse and popular breasts today. The whale suborder includes not only giant blue whales, sperm whales, and bowhead whales, but also many different species of dolphins. Species in the suborder whales still exist on Earth today. The “whale” Pakicetus is one of the earliest known ancient whales, this animal that lived 50 million years ago looked like a dog with long limbs and fur. If you look closely at the Pakicetus whale, you will see that its nose is located in the front of the head, like today’s mammals. Because the nostrils of Pakicetus whales are located in front of the mouth, when swimming they will look like dogs today because underwater, they have to almost raise their heads out of the water when swimming. Pakicetus is an extinct genus of cetacea, found in Pre-Eocene rocks in Pakistan. The strata where the fossils were found were then part of the coastal Tethys Sea. .As the ancient whales gradually entered the ocean, their body structure began to evolve in a way that was adapted to aquatic life, including the position of the neck, the nostrils gradually moving to the top of the head, Below are pictures of the primitive whale (Protocetus) and a restored image of the Basilosaurus whale, both of which show their nostrils gradually turning upward. Protocetus is one of the most ancient whale genera, which lived in the middle of the Meridian period 45 million years ago near Cairo, Egypt. It was one of the first genera of whales to have fully adapted to aquatic habitats. They are quite small, only about 2.5 m long, on the body still keep the traces of limbs with fingers connected by swimming membranes with the hind limbs smaller than the front limbs. Jaws long, with sharp teeth. The front teeth are used to catch prey and the back teeth are used to cut meat. Unlike the older predecessor Pakicetus, which lived a semi-aquatic lifestyle, Protocetus was able to develop ear canals and hear underwater sounds (but it is unclear whether they developed sonar or sonar). not yet) and developed a flattened tail like today’s whales. Their nostrils are still located on the head, they still do not have a stoma on the top of the head and rely more on eyesight for food. Basilosaurus is one of the primitive whales that evolved from land mammals and later evolved into modern day whales. Basilosaurus averaged about 18 – 20 m long and weighed about 15 tons, once distributed in North America, North Africa and Central Asia and was considered the largest animal that ever lived in its time. The ancient whale species mentioned above all belong to the ancient whale suborder, the baleen whales and the toothed whales in the ocean today all evolved from the ancient whale suborder. They appeared in the middle Oligocene, about 30 million years ago. Compared to today’s whales, their appearance is quite similar to ancient whales, but the evolution to change the position of the nostrils took quite a long time – about 20 million years. Diagram of the evolution of ancient whales. Schematic diagram of the evolution of modern whales. Modern whales have evolved to move the nostrils from the front of the mouth to the top of the head. It’s not just a change of location. The esophagus and trachea of ​​today’s terrestrial mammals are interconnected, so if our noses are blocked by a cold, we can still use our mouths to breathe instead of our nostrils. In addition to breathing, our nose also has the function of smelling. But modern whales are different, and the changes in the position of the nostrils and the changes they made to aquatic life have caused the trachea and esophagus to separate. The nostrils connect to the lungs and the esophagus connects to the digestive system, so their noses are only used for breathing, not for smelling. The nostrils of modern whales located at the top of the head actually help them survive more effectively and safely than the holes in the front of the mouth when in the ocean. But even if their nostrils are at the top of their heads, when they dive into the ocean, their noses are still underwater, how can modern whales ensure that they won’t choke? In fact, under the nostrils of whales have a very strong muscle group, they can completely close their nostrils when diving, avoiding the risk of choking on water. The separation of the esophagus and trachea also ensures that modern whales will not choke on water while hunting in the ocean. Large nostrils of baleen whales. The nostrils of a blue whale when diving into the water. In fact, all baleen whales still have two nostrils, while toothed whales have only one. The jets that whales spit out of the water are not water in their noses, but rather accumulations of water remaining in the “pits” of the nostrils, which are formed under the action of sub-lower pressure. Ocean. This prevents water from entering the nostrils, improving the safety and efficiency of breathing. However, the water column due to the whale’s breathing process once brought them great danger. In the era of whaling, sailors often relied on these water columns to locate the schools of fish. elephants. Killer whales belong to the toothed whale subspecies with only one nostril. Gray whales belong to the subspecies of baleen whales that spray water with a pair of nostrils.

Humans and the fear of snakes exist in the genetics Few people know that, ophidiophobia or the horrible obsession with snakes and round, long, legless animals in general is the most common fear in human society (1/3 of humanity is afraid of snakes). In addition, scientists have confirmed: Most primates have inherited the instinct to… be afraid and run away from snakes. The reason, prehistoric people were so afraid of snakes because they had to face giant carnivorous reptiles, not hostages like now. First is Titanoboa cerrejonensis : Nearly 13m long, weighing about 1 ton, is considered the largest snake species discovered by man However, some studies indicate that Titanoboa was a piscivore rather than a megafauna-killer. So, is it a giant but gentle animal? Titanoboa cerrejonensis. Before humans left records of Titanoboa, the title of giant snake was given Gigantophis garstini They appeared about 20 million years after Titanoboa in Africa with a length of about 11m. Gigantophis’ favorite food was the ancestor of the modern world’s elephants. Gigantophis garstini. Madtsoia madagascariensis: Giant snake that specializes in eating dinosaurs Gigantophis’ close relative is Madtsoia madagascariensis , another giant snake that lived in Madagascar for several million years during the age of the dinosaurs. They lived with iconic dinosaurs like Majungasaurus , Masiakasaurus and Rahonavis as well as giant frogs Beelzebufo . And perhaps, Madtsoia is also more than enough to eat all the dinosaurs mentioned above. Madtsoia madagascariensis. Both Madtsoia and Gigantophis belong to the ancient family of giant snakes known as the Madtsoiids. Both of these genera lived long ago, but some survived until recently in Australia. Until Wonambi naracoortensis , a snake more than 6m long has inspired the legend of the Rainbow Snake of primitive Australians This size seems modest compared to the previous monsters, but it is still significantly larger when compared to the Anaconda python. Furthermore, over time it has coexisted with giant kangaroos, marsupial lions and primitive Australians – it may have inspired the Rainbow Serpent legend. mythical animals of Australia). Rainbow Snake, one of the mythical animals of Australia. Yurlunggur camfieldensis , a reptile that the Yurlungur aborigines believe is made of bronze, specializes in hunting virgins Living in the same period and place as Wonambi is a species Yurlunggur camfieldensis. They are named after the Yurlungur Aboriginal mythology – which tells of a bronze snake excited by the smell of a young girl’s menstrual blood that would come to eat her and her family. Yurlunggur is said to be up to 8m long and is a self-burrowing aquatic species. They will hunt underwater but live in burrows with soft ground. Though non-poisonous, the terrifying force of the contractions would kill their prey, similar to most pythons today. Yurlunggur camfieldensis. Palaeophiidae, Giant water snake up to 10m long, specializing in eating whales and prehistoric sharks Come to another ancient genus of giant snakes, Palaeophiidae of the genus Palaeophiid . Palaeophiidae evolved over 70 million years ago, and like the Madtsoiids, they survived the K-PG Great Extinction. Similar to modern sea snakes, Palaeophiidae lived entirely in water, only much larger. According to researcher Gary Meaney, Palaeophis colossaeus New is the scariest of all – it can hunt whales, giant sharks in the Eocene waters. It is very large, up to 10m long. Palaeophis colossaeus. Pterosphenus , a giant warm-blooded snake, much more active than a cold-blooded reptile Another branch of the Palaeophiid genus, Pterosphenus , which is also horrifying in size: 7m. In addition, these are giant sea snakes that have the ability to reproduce early and have a warm-blooded metabolism, making them more active than many other slow reptile monsters. Pterosphenus. To the giant, tens of meters long reptiles that dominate the earth During the Pliocene (geological period), did the Australian continent exist the giant python Bluff Downs or Liasis dubungila – one of the few prehistoric animals with a common name. It is more than 10m long and is considered the largest snake ever of this continent. Bluff Downs or Liasis dubungila. In prehistoric times, branches of the python family also gained horological dimensions. One of them is Chubutophis grandis, estimated at 22m in length. And if that’s true, Titanoboa will lose the title of the largest snake in history. They lived in the Miocene with a host of giant South American creatures: Elephant-sized Caimans, giant gharials, giant tigers and giant turtles… Chubutophis grandis. Finally, let’s come to the largest venomous snake known: Laophis , closely resembles the poisonous Gabon viper, which lived on the Greek islands during the Pliocene. According to scientists, it weighs twice as much as the largest venomous snakes of the modern world, more than 4m long. This size has nothing to do with the reptiles listed above, but they are not poisonous… Laophis. As such, Titanoboa was the only nightmare snake that slithered around in ancient times. It may be the biggest, but it’s probably not the scariest.