Why do whales that live in the sea give birth to babies in viviparity?

Because the ancestors of whales originally lived on land, because of food shortages and natural disasters, they entered the ocean to live, and gradually evolved into marine mammals, and continued to retain the characteristics of mammal reproduction.

Because whales are not fishes, but mammals, the mammalian mode of reproduction is viviparous. Although whales live in water, don't classify them as fish, they have common mammalian characteristics such as breathing with lungs, viviparity, body coat, and more.

The whale is not a fish, it is actually a mammal, so giving birth to a baby is viviparous.

Whales are viviparous and belong to the family of mammals. The body structure and living habits of cetaceans are obviously different from those of any mammal, so they have been listed as a single order for a long time. Its ancestry and evolutionary history were once controversial, but with the continuous progress of related research, it has been fully confirmed that cetaceans evolved from terrestrial artiodactyls 50 million years ago.

Cetaceans produce only one calf per litter, have a long growth period, and are on the verge of extinction under human aggression1 4.

Whale species1. Baleen whales, a general term for baleen cetaceans, including blue whales, fin whales, bigfin whales (humpback whales), right whales, gray whales, etc., there are a total of 15 species in the world, of which 9 species are found in China.

2. Toothed whales, toothed whales have teeth, the teeth are conical, the number of teeth is unequal, the least has only a single tooth, the most has dozens of teeth. There are many types. One of the outer nostrils.

The skull is asymmetrical from side to side. The flippers have 5 fingers. The sternum is large.

No clavicle. No cecum. The individual variation of various toothed whales varies greatly, from the smallest being only about 1 meter to the largest being 20 meters.

The above content reference: Encyclopedia - Cetaceans.

The above content reference: Encyclopedia - Toothed Whale.

The above content reference: Encyclopedia - Baleen Whales.

Whales are "viviparous".

Although whales are named after "fish", they are not actually fish, but a class of mammals. They originally lived on land, but later entered the water due to geological changes, which allowed them to slowly evolve some characteristics suitable for the underwater environment.

The breeding cycle of whales is relatively long, generally speaking, it can only reproduce once every 2 or even 3 years. Their gestation period is also relatively long, even longer than that of humans, which may be 11 and a half months or even a year. They usually have only one litter at a time, and the newborn calves are about 5 meters long.

Like other mammals, whales have a lactation period, which is about 6-7 months.

The Earliest Whales:

The earliest whales were the Archaeocene, the Archaeocene, and the Late Eocene whales, which appeared about 55 million years ago, and their skulls were smaller than those of extant whales, and their nostrils were located in front of the head and had not yet moved to the top of the head.

The teeth are similar to those of ancient insectivorous and flesh-toothed animals, with 44 or less than 44 teeth, and the tooth shape and skull are also very similar, with only a few differences, but they already have a body shape similar to that of fish that is adapted to living in seawater.

The above content reference: Encyclopedia - Whales.

It is a mammal. Although the whale has the word fish, it is not a fish, but a mammal that lives in water, and has the same physiological characteristics as land mammals, such as breathing with lungs, constant body temperature, viviparity, etc., and has some special physiological structures evolved to adapt to the aquatic environment. Whales, like land mammals, are viviparous, and calves are born directly from the belly of the mother.

Notes:Whales have a thick layer of fat under their skin, which is called whale oil, which keeps the whale warm and can also store energy for emergencies.

Because whales have many special structures in their bodies, they can hold their breath and slow down their heartbeat for a long time, so when they sink to the bottom of the sea, it will always take a long time before they resurface. In addition to having a structure to store oxygen, when a certain part of the body needs a large amount of blood**, there will also be a special function in the body to concentrate**.

Unlike fish, whales are viviparous, generally giving birth to one litter per litter and one litter every two years.

Whales live in the ocean and have many similarities to fish, so many people believe that they also reproduce like ordinary fish. Actually, this is a wrong view. Whales themselves are mammals, not fish, and only entered the water because of geological changes, evolving characteristics similar to fish.

Their essence has not changed, they are still mammals. Therefore, they still reproduce in viviparity, rather than oviparity.

Whale sharks, a class of giant sea creatures, have always attracted attention due to their huge body and ferocious image. And about the breeding mode of whale sharks, it is also a topic that people are more concerned about. So, are whale sharks viviparous or oviparous?

How whale sharks reproduce.

Whale sharks are cartilaginous fishes that are similar to sharks but share similar ecological and biological characteristics to cetaceans. Their way of reproduction is very different from that of sharks, which are viviparous, i.e., develop in the womb and eventually give birth to juveniles. Sharks, on the other hand, are oviparous, and after laying eggs, the juveniles hatch inside the eggs and are given food to grow on their own.

Advantages of viviparity.

Viviparity has some advantages, the first of which is to ensure that the juveniles have adequate nutrition** immediately after birth, and have a higher survival rate. Secondly, the viviparous method can protect the female whale shark from being affected by too many eggs, reducing fertility pressure.

Features of whale shark littering.

There are some characteristics of whale shark calves, such as the fact that calves are in great danger. In the early days of whale shark production, juveniles are too small to escape predators, so they need to be protected by the mother whale shark. In addition, whale shark juveniles need to absorb nutrients in time after birth, so that they can grow rapidly in size.

The influence of ecological factors on reproduction.

The way whale sharks reproduce is closely related to the environment in which they live. In the deep-sea area where they live, bridges are rich in nutrients and food, so they can provide enough nutrients to support the development of juvenile fish. This provides a very suitable environment for viviparity.

If the whale shark lives in a harsh environment or has a lack of food, then the oviparous mode may be more suitable for the living environment.

Conclusion. Overall, while whale sharks and sharks look similar, the way they reproduce is very different, and whale sharks are viviparous. This ensures a higher survival rate for the pups after birth, while also reducing the stress on the mother whale shark in terms of fertility.

However, the factors of the whale shark's living environment also determine whether a breeding method can be prevalent among them.