Whales are sociable, air-breathing animals – mammals – that nurse their young with their milk and provide exceptional care and instruction in the early stages of life. Many hold the opinion that whales are extraordinary, and for a good reason. They have an almost otherworldly quality. Many individuals find that interacting with whales improves their life. Whales are one-of-a-kind creatures that are stunning to look at. And they are much more interesting once you dive deeper (pun unintended!) and begin to learn how the evolution on whales took place.
The history of the evolution of a whale is lengthy and complex—some changes need to be made for terrestrial animals to transition into marine environments. After first living on land, whales lost their rear limbs, flattened down their tail, grew paddle-like flippers, and slimmed down to navigate the water better. This was the evolution of a whale from land to sea. And this is how did whales evolve is believed to be.
Evolution of whales timeline: Stages
This incredible evolutionary journey is amongst biology’s most fascinating. Adaptation has been a crucial concept in the evolution of a whale, and it goes hand in hand with Darwin’s theory of natural selection. Species had to evolve and adapt to new conditions as the world evolved, which is how the evolution on whales began. Natural selection was primarily the driver behind this outcome.
Incredibly well adapted to a marine environment, the whales we know today are remarkable creatures after the process of evolution on whales which is still in work. Adaptations to the marine environment have been favored over millions of years. Blowhole nostrils have migrated to the crown of the head. Both the fore and hind limbs have been replaced with fins. The fur and hair on the body are entirely gone. There were several simplifications made. The tail has become a strong propeller linked horizontally to the spinal cord. Because of these changes, drawing clear lines between whales and their nearest relatives is difficult. Let us look how did whales evolve by having a look at the ladder of the evolution of whales timeline.
Mammals specialized for aquatic life
So, what did whales evolve from? Whales are animals just like us. They can breathe the air because they have lungs. A steady body temperature of 37 degrees Celsius indicates that these creatures are warm-blooded. Their young grow and get their first nutrition in the mother’s womb, from the placenta, and then from her milk after delivery. The evolution on whales has been shaped by a number of factors, including changes in the environment, the availability of food, and competition with other species.
Land-roaming whales (on four legs)
The second stage of how did whales evolve. The ancestors of today’s most significant marine creatures originated on land. Discover their incredible adventure as it takes them from land to sea. Whales are now fully aquatic and well-adapted to their aquatic lifestyle, yet these marine creatures once walked on all fours. About fifty million years ago, their predecessors roamed the earth.
A four-legged goat-sized Pakicetus is one of the earliest cetaceans recognized by scientists. One of the fascinating paths of evolution of a whale is the one that led to whales from Pakicetus.
Back to the water
This stage of how did whales evolve involves the evolution of whales from land to sea. Sea animals have several adaptations they didn’t have on land. Evolution forces the adaption of species to their environment. Whales couldn’t walk with four limbs. Therefore, they’d need a new method. The water would surround them instead of air. They must be able to detect and grab prey and breathe underwater. Whales required a means to breathe air underwater. Frontal nostrils shifted to the tops of their skulls, creating blowholes.
Jaws and teeth changed to grab prey. The upper jaw became more significant and broader to fit prey, and teeth changed from carnivores’. The uniformity of the replacement teeth evidenced a change to homodont teeth. Skull changes were required to fit the melon in front of their braincase. Melon fat helps whales perform echolocation by focusing sound. The whale’s body became more streamlined to travel across the seas, having a lengthy body to push through thick water. Dorudon, which existed between 40 and 33 million years ago, represents a further step along this path of the evolution of a whale.
This five-meter-long creature featured natural flippers and tiny, stubby back legs. Its whole life was spent underwater. Thus it was a strong swimmer. Additionally, it had an aquatic birthing process.
Journey to America
Modern whales’ ancestors traveled from India and Pakistan to their current areas. When did they go where? Fossils can address this question but are too fragmented to be precise. In 2011, a fossil of a four-legged whale was discovered in Peru. In this stage of how did whales evolve, this ancestral whale supports the theory that a westward migration preceded a northward movement fewer than 10 million years after the first whales appeared in India and Pakistan. The path of evolution on whales.
Whales without teeth
The ancestors of today’s whales are descended from Dorudon, an extinct whale genus. Around 34 million years ago, a subset of whales began experimenting with a novel food consumption approach. Their skulls were more flattened, and inside their mouths were feeding filters. The evolution on whales from land-dwelling mammals to ocean-dwelling creatures is a fascinating subject that has captivated scientists for centuries.
In this evolutionary stage whales had a type of tooth called baleen, including blue and humpback whales. Other types of whales, such as dolphins, porpoises, orcas, and sperm whales, maintain their natural teeth throughout their live .One of the most significant events in the evolution of a whales was the development of their streamlined bodies, which allowed them to swim more efficiently in the water.
The stage of Modern Whales of how did whales evolve there are now two prominent families of whales, the odontocetes (toothed whales) and the mysticetes (baleen whales). Approximately 34 million years ago, they shared a progenitor who most likely did not have baleen or the ability to utilize echolocation. The significant biological changes in the waters over the last 5 million years have likely contributed to the diversification of whale species.
As the oceans cooled and the currents shifted, a second influx of diverse whale species appeared around 15 million years ago. At the same time, the variety of crustaceans and mollusks that some whales eat has grown. This is how whales evolved and are still evolving.
The original mysticetes were around the size of a modern-day minke whale, or 5 to 9 meters in length. It was only around 4.5 million years ago that whales are thought to have grown to their current size. Mysticetes exploded in population just as the temperature cooled and huge ice caps formed in the northern hemisphere. Ice melts in the spring and summer, releasing nutrients into the open ocean, where they collect along the beaches. Plankton, drawn there by currents, congregate in these zones, where they thrive in the presence of abundant nutrients. Seasonal concentrations of plankton begin to build in the ocean, sometimes thousands of kilometers apart.
Today, in the evolutionary stage of a whale, size is now a heavily selected factor. This means most overweight individuals can travel farther to reach these newly created feeding grounds because of increased energy stores. The age of the giants replaces the period of the lesser ones. There are several upsides to one’s size. Generally speaking, giants live at the very top of the food chain and are very seldom attacked by smaller creatures. However, they are in greater danger of extinction during environmental upheaval or crisis. Some scientists believe that the evolution on whales may have been influenced by the emergence of predatory sharks during the early days of the oceans.
Now as we have studied how did whales evolve. The question arises is of “Now?”. Whales today are still changing and adapting. Changes in the environment and the dynamics of species interactions characterize ecosystems. Therefore, it is necessary to adjust to new circumstances constantly. Multiple factors, including global warming, decreased prey quantity, and ocean pollution, are putting evolutionary stress on today’s whales. Because of their massive size, they are especially susceptible to starvation.
Around the time the Oligocene epoch was winding down, some 25 million years ago, plenty of toothed whales were swimming the seas of the planet. They had all developed farther from previous whales, but none were like the ones we have today. There is speculation that a shark-toothed dolphin gave rise to the current killer whale somewhere around this period. The killer whale’s lifestyle is hypothesized to apply to Squalodontidae.
Modern sperm whales developed from Physeteridae, a sperm whale that existed then, whereas beaked whales emerged during the Miocene epoch, lasting from 25 to 5 million years ago. Even though their gaps throughout the fossil record, it is generally accepted that all extant families of whales were well-established by the Miocene epoch. Some marine mammal fossils, including those of belugas, narwhals, and porpoises, need to be better understood. This is the whole process of the evolution of whales from land to sea and now to the sea only.
Only one living member of the Eschrichtiidae family, the grey whale, has fossil records dating back more than 100,000 years; these records show no significant changes to the present whale. It has been hypothesized that the Eschrichtiidae whales developed apart from other whales. The Balaenopteridae family, which includes the blue whale, humpback whale, and other living whales, descended from the extinct Cetotheriidae. For around 7 million years, these two species shared the waters.
During its peak, the family Cetotheriidae was home to about 50 different whale species. Many members of this family have developed a giant skull, including baleen in their mouths, among other adaptations. The jaws loosened up at this phase, allowing for a more substantial gulp and easier access to vast quantities of plankton. Fossil evidence is lacking, but right whales likely existed during this period. Some fossils are 25 million years old.
This was the evolution of whales timeline from pakicetus to Basilorous.
In this post, we picturized the whales evolution chart with the help of a timeline. Better, stronger, and more robust divers, whales today are perhaps the least-understood marine mammals. Scientists have struggled to piece together the events that led to the evolution of a whale for a long time. It seems puzzling that an animal adapted to land life would return to the sea, but it turns out that food was the primary driving factor here. Whaling likely began some 50 million years ago due to this behavior.
Many people have the mistaken belief that whales are inherently superior to humans. However, in some instances, whales’ supposed advantages may be traced back to the loss of genes. Because whales inhabit saltwater habitats with a few exceptions, genes involved in feeding—such as those responsible for saliva production or those that code for sodium reabsorption by the kidneys—have been lost. Since they spend so much time at sea, they never run out of salt and don’t need their food to be lubricated. This is answer to what did whales evolve from and what they are now.
A lack of melatonin, the well-known hormone that controls the sleep cycle, affects whales’ resting behavior. In cetaceans, breathing is a deliberate effort. Thus, if one were to slip into a deep sleep, there would be an increased chance of drowning. The study of the evolution of a whale has led to many important discoveries about the history and diversity of life on Earth.
Another set of genes that cetaceans have lost are helpful to terrestrial animals but hinder diving performance. According to research, blood clotting genes, fibrosis, and other lung disease genes have been lost in specific individuals. Diving cetaceans no longer possess a gene that, in a roundabout way, raised the danger of DNA alterations.