Humpback Whale Reproduction 101: Insightful Guide

humpback whale and calf

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Normally, whale reproduction is not very easily observed, let alone recorded, so a lot of what goes on around the mating and breeding of these gentle giants is still uncharted territory.

Yet luckily, humpback whale reproduction is a slightly different story.

The humpback whale is one of the most beloved sea giants for both, whale-watching tourists and marine scientists alike.

One of the reasons is their breathtaking size, however, this whale is not even close to being the largest species swimming in our oceans, so what’s its charm?

Truth is the humpback whale is a total show-off who seems to enjoy breaching, tail slapping, and flipper splashing as much as you and I enjoy watching these acrobatic displays.

The spectacle put on by a humpback is quite enthralling for anyone watching.

Fortunately for you and me, its apparent desire for attention has allowed scientists to learn a lot about the humpback making it the most studied whale species out there.

Today I have gathered everything you need to know for you to find a full guide to humpback whale reproduction below. 

How Does A Humpback Whale Reproduce?

First of all, let me remind you that humpback whales are mammals therefore sexual reproduction is a must, as well as live births.

These whales are polygamous with both sexes breeding with multiple partners each mating season thus increasing their chances of success.

After the breeding season is over male and female pairs will dissolve and each individual will go their separate ways without any close bonds ever forming between them.

On the other hand, the bond between mother and calf is especially strong; there’s no parental care given by the male.

Female humpback whales go through a gestation period of almost a year, 11.5 months to be exact, before giving birth to a single calf that will be born with an impressive weight of around 1.5 metric tons and a length of up to 4.5 m / 14.8 feet.  

How Often Do Humpback Whales Give Birth?

After reaching sexual maturity between the age of 4 to 10 female humpback whales give birth every 2 to 3 years on average returning to their breeding grounds to deliver a single calf that will remain by her side for about 1 year. 

Producing an offspring of such large proportions is no easy feat, now imagine what it is like to feed this baby giant!

Newborn humpback whales gain around 45.4 kg / 100 lbs per day by consuming around 50 gallons of milk daily. 

How Do Humpback Whales Mate?

There is definitely A LOT going on underwater during humpback whale mating season!

I’ll break it down below:

First, the whales will arrive at their breeding grounds which are by preference warmer tropical waters.

For populations in the southern hemisphere, breeding takes place from July until October. Northern hemisphere whales will breed from December through March. 

Just that first step is a huge accomplishment by itself as in order to arrive at such grounds the humpback whales must first undergo one of the longest migrations in the animal kingdom swimming about 8047 km / 5000 miles.

Once gathered on breeding grounds several males will surround an estrous female and vigorously and aggressively compete for the chance to mate with her.

These intense displays include racing, tail slapping, rolling, charging, and plenty of vocalizations.

When the female humpback chooses a lucky male they will then engage in a complex ritual that involves swimming and rolling together, diving down into the deep blue, and resurfacing vertically facing one another with their genital slits pressed together. Or so is believed…

What do I mean by this?

Turns out that even though humpbacks are the most studied whale species an actual breeding event has yet to be recorded!

Scientists have theorized how the event might play out by looking into the behavior of closely related species such as the right whale. 

Definitely tells you a lot about how much of what is happening underwater is still a mystery.

More On Humpback Whale Reproduction

Although the act of breeding has never been recorded there is a lot more information available regarding the mating and calving process.

For example, male competition to win over a receptive female can get so intense it has ended with dead male suitors.

A fact I personally find really interesting is that pregnancy and lactation can coexist!

It is not uncommon for a female to get pregnant soon after birthing a calf and she can continue to provide the necessary nutrition for her offspring while simultaneously producing a new one.

Something that is mindblowing when you take into account that a humpback whale is about half the size of a blue whale is the fact that there is at least one known hybrid between these two species!

Hybridization events probably occur more often than we think but scientists only learn about them by chance when a whale sample from a whaling ship or a black market ends up in a lab.  

Individuals that are a result of hybridization tend to look like one of the parents so identification of hybrids with the naked eye can be tricky and misleading. 

And lastly, no one has ever been able to witness or record a humpback whale birth! In February 2020 a whale-watching boat off the coast of Hawaii was able to record the first and only video of a whale giving birth

In the video which you can find here, you will see the calf’s tail coming out of the mother’s genital slit but the whale and her escorts left before the baby was born.

Final Thoughts

Something I have learned throughout my life as a lover of everything that relates to the oceans is that you and I have no idea of all the secrets that still remain. 

The fact that an animal so large, so curious and so thoroughly studied has somehow been able to keep such an intimate part of its life to itself is something that baffles me and motivates me to learn as much as I can about such amazing creatures.

I hope that I was able to provide you with some insight into everything that is known to go into humpback whale reproduction and can’t wait to keep sharing information about our beautiful ocean neighbors with you.