Why Do Whales Migrate?


whale

Whales migrate great distances and this behavior caught my attention. I wanted to find out why they migrate and their motives for migrating every season.  

Migration is the seasonal movement of animals from one place to another. Whales migrate to search for richer feeding grounds, and to find favorable breeding grounds.  

There are over 80 species of whales, and each has its own movement pattern. Some whales travel long distances during migration that may amount to thousands of miles.

I wanted to write this article to help me find out why whales migrate and give you the answers to questions you may have about whales migrating.

Gray whale

Why Do Whales Migrate?

Primarily, the reason whales migrate is to search for a plentiful supply of food. During the warm seasons, whales migrate to colder waters where their food source is plentiful. When the weather changes and the water becomes severely cold, whales have to alter their location.  

When the water is colder, the food becomes more scarce, so whales have to migrate to warmer waters where there is a good supply of food. Whales migrate towards the poles in the summer, and towards the more tropical waters of the equator in the winter.

Blue whale

Whales also migrate for reproduction reasons. Whales take advantage of the summer weather and migrate to colder water to reproduce. Whales will migrate to their mating grounds. Whales have specific locations where they gather for reproducing.

Want to know which whales you can see in North America? Find out in this guide I have written.

Whales migrate between feeding and mating seasons. They tend to migrate towards cooler waters during the warmer summer months to stock up on food and to replenish their supply of fat before the cold temperatures come around once more.

Whales migrate to a familiar place where mating takes place, and once their mating season ends, each whale will then leave that area. 

The movement of the whale is also as a result of the migration of their prey. Whales will follow the migration patterns of their prey. Whales will travel wherever their prey migrates so that they can continue their journey without having to worry about finding a fresh source of food.

If you would like to know what the ten largest whales are in North America, I have written an article. You can find this here.

Adult grey whale jumping out of the water, Baja California, Mexico

Do All Whales Migrate at the Same Time?

The whale’s migration time, distance and destination differ from one species of whale to another. The main factor for this is the time of the gestation period, and the time it takes to give birth. These factors have an impact on when, where, and if these marine mammals migrate to new locations during certain times of the year. 

Whales will not migrate long distances to mate or give birth to calves. Whales can mate at any time of the year. The difference in the gestation period among multiple species of whales results in a different time of migration. 

Killer whales migrate do not have a specific breeding ground. Orcas move to different areas to give birth. The gestation period of a killer whale is between 15-18. As the gestation period is so long, this would overlap into their feeding season. Killer whales will give birth in the feeding grounds.

Narwhals and the beluga whale have time to migrate to a new ground to give birth. They have a gestation period that exceeds the 11-12 months cycle of some other whales species.

Ever wanted to watch whales in North America? Find out where in a guide I have written.

With this gestation period, both Narwhals and beluga whales have time to travel from one area to another. Neither of these species migrates over vast distances from cold weather to tropical environments the way other whales do.

Whale

Blue whales and humpback whales have a similar gestation period of 11-12 months. This timescale allows them to give birth in warmer environments where they also mate. They become pregnant in the same area that they give birth, almost a year later.

These migratory patterns make it possible for their newborn calves a chance to be born in a warm and secure environment. The fact that they can have their calves in the same area each year makes it easier than dealing with births being scattered throughout their feeding grounds.

It is also better for the whales to have them in one area, rather than during a long migration trip.

Sperm-whale

Where Do Whales Migrate?

In general, whales migrate towards the colder poles in the summer, and towards the tropical waters of the equator in winter months. This is a migratory pattern which helps the whales to take advantage of the colder waters with more food in the summer.

As the food sources in those areas run out, the whales will then migrate to warmer waters to give birth to calves.

The humpback whale is known to undertake an annual migration from their summer feeding grounds at high latitudes. They then move to their winter breeding grounds in subtropical and tropical waters.

Humpback whales will feed in Alaska during the summer, before moving over the warmer climates of Hawaii in the winter months.

Whales migrate north to warmer tropical breeding grounds, and there are several reasons for this. By moving to a lower latitude, the risk of attack on the young calves by killer whales is lower.

Calm waters further north also provide a more tranquil environment for calves to swim in, resulting in less energy used. Calm shallow waters also have a reduced predation risk from other predators. There may also benefit to calf thermoregulation being in warmer water.

The gray whale is another whale species which migrates north each spring. By migrating North, they feast on plentiful food sources, growing fast in the rich feeding waters of the Arctic.

Gray whales also migrate south each fall to mate and give birth in lagoons on Mexico’s Baja Peninsula. They are fond of this migration pattern every year of their long lives.

Blue whales which are in the Pacific sea migrate from California, down to the warmer weather of Mexico and Costa Rica.

North Atlantic right whales appear to move between cold waters off Northeastern US and Canada, to waters off the states of Carolina, Georgia and Florida. 

Whales come very close to the shore when migrating. Find out why in an article I have written here.

Which Whale Has The Longest Migration?

The gray whale is considered to have the longest migration of any marine mammal. The gray whale travels 10,000-12,000 miles on a round trip between their breeding grounds off Baja, California to their feeding grounds in the Bering and Chukchi Seas off Alaska.

Gray whale

The longest whale migration on record is a gray whale which broke the marine mammal migration record. The whale travelled from Russia to Mexico and back again. This was at a distance of 13.988 miles in just 172 days. 

The second-longest ever migration was by a humpback whale. The whale was sighted off the Antarctic Peninsula in April 1986 and then sighted again off Colombia in August 1986. It was estimated to have travelled over 5,100 miles. 

There are so many species of whale, and not all species of whale migrate as close to shore as the gray whale or humpback whale. There are many migration routes for whales that are still unknown.

The migration of a whale is due to changes from the seasons. The changes in season also affect the food that whales need. The migration pattern of the food that a whale eats can play a huge part in where the whale migrates. Whales also migrate due to reproduction.

Gray whale

Whales need a favorable environment to give birth and to help the calf survive through the first few months. 

Ever wondered how whales breastfeed underwater. I know, probably not. However, if you are now wondering, you can find an article I have written here.

References

Bernhard Grzimek, Schlager, N., Olendorf, D. and American (2003). Grzimek’s animal life encyclopedia. Detroit: Gale.

Carwardine, M. (2010). Whales, dolphins and porpoises. London: Dorling Kindersley.

Carwardine, M. (2017). Mark Carwardine’s guide to whale watching in North America : USA, Canada, Mexico, where to go, what to see. London: Bloomsbury.

Hadoram Shirihai, Jarrett, B., Graeme Cresswell and Kirwan, G.M. (2019). Whales, dolphins and seals : a field guide to the marine mammals of the world. London: Bloomsbury Wildlife.

Martin, T. (1990). The illustrated encyclopedia of whales and dolphins. Hodder.

Nowak, R.M. and Walker, E.P. (1991). Walker’s mammals of the world. Baltimore: Johns Hopkins University Press.

Perrin, W.F., Würsig, B.G. and J  G  M Thewissen (2002). Encyclopedia of marine mammals. San Diego: Academic Press.

Richard John Harrison and Bryden, M.M. (1990). Whales, dolphins and porpoises. London: Merehurst.

Williams, H. (1988). Whale nation. London: Cape.

Wilson, D.E. (1999). The Smithsonian book of North American mammals. Washington: Smithsonian Inst. Press.

May, J. (1990). The Greenpeace book of dolphins. London: Century.

Bryan Harding

Bryan has spent his whole life around animals. While loving all animals, Bryan is especially fond of mammals and has studied and worked with them around the world. Not only does Bryan share his knowledge and experience with our readers, but he also serves as owner, editor, and publisher of North American Mammals.

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