For a number different whale species the path to reproducing offspring begins by leaving their local feeding grounds and preparing for their long migration trip to their breeding/calving grounds where the male whales compete with one another for the right to mate with a female and have a chance to pass on their genes to the next generation.
Depending on the species some whales may travel thousands of miles from their feeding grounds to their mating grounds in order to look for a mating partner or (if the female is already pregnant) give birth to their offspring.
Although some whale species are known to migrate long distances there are a number of species that inhibit the same area throughout the year or follow the migration patterns of their food rather than looking for an ideal mating environment.
For instance the humpback whale is known to migrate up to 16,000 miles per year between its feeding grounds and mating grounds while the bowhead whale tends to spend the entire year in Arctic/sub Arctic waters.
For many species mating season occurs during the colder winter months when their food supply migrates to warmer climates and their native feeding grounds (near the northern/southern polar hemispheres) begin to freeze over and/or become extremely cold.
The freezing water, diminishing food supply and internal mating clock encourage the whale populations to seek out a new location where they can meet up for their annual mating season, reproduce and bare offspring.
In order to find a more stable environment these whales travel towards the equator where the weather is warmer and produces a suitable environment for mating and having children while also providing some species with better protection from predators due to larger pods formed by mating groups.
In some situations whales are also able to find mating areas where little to no predators exist.
During the long migration trip some species of whale are known to fast for several months and will live solely off of the fat they stored in their blubber during feeding season.
Once the whales arrive at their breeding grounds and they are ready to mate the male whales begin looking for a mating partner by courting the female whales and competing with other males.
The courtship period
The first phase a male whale goes through when it attempts to find a female mating partner to reproduce with is to attract a female whale during a courtship phase.
During the courtship period unrelated male whales will compete for the right to mate with the female whales first by showing their worthiness, dominance, competitive advantages and strengths.
Some of these courting activities may include breaching (Lunging out of the water), fin slapping (slapping their fins against the water), singing (producing low-frequency melodic tones) and giving gifts to the female among other activities and gestures.
Some male whales may also charge at one another and fight over a female whale.
Although male whales are known to compete among one another for the right to mate with a female it is rare that the whales will cause severe physical harm to one another, at least not with most species.
A few species of whale such as several of the beaked whale species are known to be quite aggressive and may scar other whales or obtain fractured beaks from intense fighting.
For a number of whale species it is common for the female to mate with several males in a single season to increase her chances of producing offspring.
To give each male the best opportunity for reproducing some species produce large amounts of sperm which is believed to help wash out the previous males sperm in an attempt to impregnate the female whale with its own sperm.
Mating season will continue for several months until all of the whales have had sufficient time to mate or bare offspring.
Once mating season ends the whales will travel back to their mating grounds (assuming they migrated) with adult males likely leaving first and the pregnant/child baring females leaving last.
The gestation (pregnancy) period
Just as humans have a pregnancy period female whales also carry their children in their womb during their gestation period (the time between conception and birth).
The gestation period for a female whale can be anywhere from 10 months to 17 months and varies from one species to the next.
Depending on the species it is common for the female whale to give birth in the mating grounds she was impregnated in.
While in the womb the baby whale receives nutrient rich blood through the umbilical cord.
The umbilical cord will also serve as a way to remove waste and toxic chemicals from the womb.
As far as reproductive cycles go female whales are likely to give birth to a single calf once every one to six years or so while the female remains fertile; giving birth to twins is rare.
At the end of the gestation period the female whale is finally ready to give birth.
During birth the baby calf will generally end up being born tail first to help prevent the possibility of the calf drowning, however some calves are born head first.
In order to feed her child the female whales mammary glands produce a thick paste like milk which is excreted from her nipples and through the water to her calves mouth.
The thickness and consistency of the milk helps minimize the chance that the milk will dissolve in the water.
The mother will continue nursing her child until it is able to hunt for food and survive on its own.
This can last anywhere from 6 months to 2 years depending on the species.
Once the child is able to hunt for itself and reaches maturity the young whale may choose to spend a few more years with its mother or head out on its own.
On average it takes a whale 6 to 15 years to sexually mature, at which point the whale will be capable of baring offspring of its own.
Monogamous? Not me
Unlike other mammal species that mate for life whales are not monogamous and will mate with several partners over the course of their life.
In fact a single female whale may mate with several males during a single mating period.
As stated earlier during mating season after a female mates with one male another male may attempt to wash out the previous partners sperm by producing large amounts of his own.
This is likely done to maximize the current partners chances of reproducing his own offspring.
After mating season ends certain male species may leave the female whale and travel off until the next mating season comes around.
The female whale on the other hand will give birth to her offspring and raise it until it is able to hunt and survive on its own.
In order to protect herself and her child some female whales will form groups with other females and their children.
Once the child grows up it may choose to stay with the pod or form new relationships with other pods.
Other species such as the killer whale are known to form lifelong bonds with their family and friends and several generations of family members can be seen together in a single pod.
These marine mammals may only separate to hunt for food or find a mating partner since they prefer to mate with members outside of their pod.
As with other factors the reproduction practices, mating seasons, migration patterns and social structures of a species can vary greatly from one species to the next.