The Oil Tankers of the Desert

Max Fursman

The Grey Whale makes one the longest migrations of any mammal and now they are dispersing further afield following the cessation of whaling.

Large scale migration is common in the animal kingdom. Many creatures journey long distances, such as the Arctic Tern on its 71,000Km journey from pole to pole, [1] or the Monarch Butterfly journeying from the Canadian borders 5,000km to Mexico. [2]

However, few creatures make migrations between such drastically different habitats as the North Eastern Pacific Grey Whale.  In the winter months[3] the Grey Whale travels 20,000km from its cold, deep water Arctic feeding grounds, to the shallow warm lagoons of West Mexico and California that are its ancestral breeding grounds.


A Californian Grey Whale Image Source

These breeding lagoons were first discovered and documented back in the 1860s by Charles M. Scammon, a naturalist and whaler. [4] Imagine his shock at seeing whale spouts gracing the skyline in the low productive inland lagoons in the hot, arid regions. Such sightings prompted the name Desert Whales for living in the hostile regions, a name that fell out of fashion upon further study of their migration.
As camels are the ships of the desert, these much larger beasts must be the Oil Tankers of the Desert (especially for the whalers of the time).


The Artic Goliath in the warm desert like waters of West Mexico Image Source

Travel’s Log

During summer, they live in the Arctic  areas rich in their food; bottom-dwelling organisms. The whale feeds mainly on benthic crustaceans, scooping up sediments from the sea floor and filtering out small sea animals, including amphipods from the sand, water and other material with its baleen: a comblike strainer of plates in the upper jaw. [5]

As Autumn draws in there is less sunlight, and so less food. The water turns colder and the northern ice pushes southward. These changes prompt the Grey Whales to set off on their two- to three-month journey south to the warm-water lagoons 10,000km away.

The 20,000 km round trip of the Grey Whales migration from the frigid productive waters of the Arctic to the tropical desert like regions of the tropics Image Source

The first whales, usually pregnant mothers and fertile females, begin arriving in the lagoon of Baja California in early January.
Over the next 6 weeks the majority of the Grey Whale population in the Pacific will have arrived at this destination, and lagoons will be a clustering of mating and calving. [6]

Once mating is over by about March, males and non-mother females will begin leaving the lagoons to go back to the feeding grounds, leaving behind mothers and calves. The calves need to be prepared for the journey, strengthen their swimming and build up blubber levels from the fat rich milk the mothers provide. This takes roughly another month or even two after the rest of the population has left.

But why these warm, shallow, lagoons? What makes these areas such a beneficial breeding ground for deep water arctic mammals?

The shallow waters make a safe training ground for young whales, the waters keep them warm and buoyant and provide just enough current to strengthen their muscles. The shallow, narrow entrances serve to make it difficult for Orca, the whales main predator, to hunt.

While the births commonly take place in the lagoons, some whales give birth during their southward migration as the gestation period of 11-13 months means there’s a chance of birthing early if the female is fertilised early the previous year.

final whale#s chart
The number of sightings of Grey Whale at Point Reyes California reflects the migration pattern Image Source

Sadly, giving birth en route is not compatible with survival, and often many youngsters can be found abandoned along the Southern California Shoreline. The female is simply unable to assist the calf in swimming in the deep ocean so early. It is thought that in the past early birthing could occur in the bays of Los Angeles or San Diego, but the traffic and noise that exists there now makes this unfeasible. [7]

Those calves that are birthed in the lagoons still aren’t safe though. Once they have grown enough to leave the lagoon they must make the long journey north, swimming in deep oceans for the first time. Orca know that during this time there are weak calves making this journey and the route home if often lined with predators, and no bull is around to help drive them off. Instead the mother becomes more aggressive in nature to protect her young, leading to the name “Devil Fish” by Whalers for the attacks on small crafts that came from this behaviour. [6]

Mothers are very protective of their calf ensuring it will survive and that their extreme investment in both energy and time pays off Image Source

Mostly thanks to whaling, many populations became victims of extirpation throughout the world; along European coasts in 500 AD and the American coasts in the 17th/18th century.
The current population is only about 20% the size of prewhaling days, but the whales were taken off the endangered species list in 1994 and since then populations have been growing. [9][10]

Recent sightings in the Mediterranean Sea and off the coasts of Namibia [11] are leading many to believe that either the whales are having to disperse further afield due to expanding populations, or are returning to ancient breeding grounds that were lost in the past due to declining numbers.

Whatever the reason is, the whales are setting sail, and it is encouraging to see these natural oil tankers traversing the seas alongside our steel counterparts, illustrating that humans and the rest of the natural world can live side by side.

Hopefully the population will continue to grow Image Source



  1. Fijn, Ruben C. et al. “Arctic Terns Sterna Paradisaea From The Netherlands Migrate Record Distances Across Three Oceans To Wilkes Land, East Antarctica“. Ardea 101.1 (2013): 3-12. Web.
  2. Monarch Migration“. Monarch Joint Venture. N.p., 2016. Web. 18 May 2016.
  3. The Marine Mammal Center“. N.p., 2016. Web. 18 May 2016.
  4. Scammon, Charles Melville. “The Marine Mammals Of The North-Western Coast Of North America.” New York: Dover Publications, 1968.
  6. WOLFSON, F. H. “Gray Whale Behavior”. Science 195.4278 (1977): 534-535. Web.
  7. Jones, Keith, E. “Gray Whale Facts And Figures – Gray Whale Breeding And Migration”. N.p., 2015. Web. 18 May 2016.
  8. Jones, Mary Lou, Steven L Swartz, and Stephen Leatherwood. “The Gray Whale.” Orlando, Fla.: Academic Press, 1984. Print.
  9. Alter, S. Elizabeth, Seth D. Newsome, and Stephen R. Palumbi. “Pre-Whaling Genetic Diversity And Population Ecology In Eastern Pacific Gray Whales: Insights From Ancient DNA And Stable Isotopes“. PLoS ONE 7.5 (2012): e35039. Web.
  10. Gray Whales, Gray Whale Pictures, Gray Whale Facts – National Geographic“. National Geographic. N.p., 2016. Web. 19 May 2016.
  11. Hoare, Philip. “First Grey Whale Spotted South Of The Equator“. The Guardian 2013. Web. 18 May 2016.

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