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The term whale has been generalized to refer to a variety of large marine cetaceans, which are mammalian animals that are adapted to aquatic life. However, from the taxonomic point of view, this designation is more reduced, and only those species that are within the group of mysticetos (baleen whales), animals that lack teeth, but instead possess baleen, which are elastic keratin structures, located in the upper jaw. These beards allow them to nourish themselves by retaining food when they expel the water they have ingested, serving as a kind of filter.
It is a fascinating group, one of the reasons is that here we find the largest animals on the planet, like for example, the blue whale. At AnimalWised we want you to know more about them, so in this article we specifically present information about how whales are born.You may also be interested in: How do whales reproduce? Index
- How and when do whales mate?
- Whale Gestation
- How is the delivery of a whale?
How and when do whales mate?
Whales are generally seasonal migratory species, since they usually define specific areas for reproduction and others for feeding. However, there are exceptions, such as the humpback whale that inhabits the Arabian Sea, which according to studies is considered a resident of the area. This preference of animals to reproduce or feed in a particular area is known as philopatry, and it varies from one species to another.
In general, whales they move in winter to warmer waters to carry out their reproductive process, since the young at birth require a period for thermoregulation until they can move to colder waters. The males in some cases can compete for the females, for which it is possible that in some species there are certain confrontations to achieve fertilization of the female. On the other hand, it can also happen that in a group of whales ready to reproduce there are several males but only one female, and this couple with all of them without any confrontation taking place. In the end, the female will become pregnant with the male with the highest sperm quality and, in this sense, the males manage to produce large amounts of this fluid to ensure their reproductive success..
Courtship is present in this group of animals, being able to last more than one hour and include on the part of the male vocalizations or elaborate songs, swimming with certain movements of the body and even friction with the female. During intercourse, the male takes out his penis, which is inside his body (as well as his testicles) and leaves the genital cleft only to introduce it to the female, which once inside it, deposits the seminal fluid, withdrawing it quickly . Afterwards, the female will have been fertilized and must become pregnant.
Whales mature sexually between 5 and 10 years of age, but females do so earlier than males. Once the female has been fertile, the gestation period begins, which it can last between 10 and 16 months, depending on the species of whale.
On the other hand, whales usually gestate a single calf every two to three years, however, there are reports that these lapses may narrow in some species, especially when there is an increase in the mortality rates of newborns or younger.
These are some examples of the gestation period in some species of whales:
- Humpback Whale (Megaptera novaeangliae): 10-12 months.
- Blue whale (Balaenoptera musculus): 11-12 months.
- Southern whale (Eubalaena australis): 12 months.
- Boreal whale (Balaena mysticetus): about 14 months.
- Gray whale (Eschrichtius robustus): 13 months.
Given the gestation time that whales have, they usually give birth near or in the same season in which they reproduced.
How is the delivery of a whale?
Mysticetes, like almost all mammals, are animals viviparous, so the embryo grows inside the female, on which it depends throughout this period. In the end, the calf is born developed and begins its process of suckling from the mother.
As we have mentioned, generally the whales make long migratory trips, so parturition can occur during these movements or in different places from where fertilization occurred. At the time of parturition, whales can increase their swimming speed, show energetic movements and, if they do so on the surface, they can be observed blowing. The calves usually at birth they do it by the tail, so this makes it easier to start swimming when they are completely out of the mother's body. However, this does not always happen, it can also happen that the baby has developed in such a way that at the time of birth it must do so by the head.
The lactation and maternal care period of whales can last until a year, in which the calf will stay with its mother to feed. Whale milk is a thick substance with high content of fat and other nutrients necessary to satisfy the requirements of the calf, which will increase its weight and size considerably in a short time.
Next, we leave you a video where a whale appears giving birth to a calf.
Whales, due to their majesty, have caused great attraction to human beings, since they are even larger than the dinosaurs themselves. However, history has recorded that indiscriminate hunting towards these species has been truly irrational, to the point of putting them in Danger of extinction. Also global warming, the impact on the oceans and the irruption in the migratory corridors of these animals cause significant damage to their populations. At a global level, there are various initiatives and institutions in charge of generating various actions for the conservation of whales.