GEOGRAPHY

Grey Whale Spotted South of the Equator
For the first time in recorded history, a grey whale has been seen in the Southern Hemisphere. The sighting, off the coast of Namibia, has scientists wondering if the cetacean is reclaiming an ancient migration route or just plain lost.

Discussion Ideas:

• A species range is the area where a particular species can be found during its lifetime. The grey whale spotted off the coast of Namibia is a whole hemisphere and an entire ocean out of its species range! Read the first two pages of our short encyclopedic entry on species range. What factors do students think contribute to grey whales’ current species range? Do they think different factors have contributed in the past? What factors do they think contributed to the Namibian whale being so radically off-course?
  • Current Species Range Factors
    • Seasonal change and the extent of sea ice usually limit the species range of grey whales. Whales cannot penetrate the kilometers-long, meters-thick winter ice that usually blocks the fabled “Northwest Passage” of the Arctic Ocean.
    • Climate also helps determine the migration patterns of grey whales. Every autumn, the North American population of grey whales migrates from the nutrient-rich, cold waters of the Arctic to the warm lagoons of Baja California, where the whales arrive in spring. Grey whale mothers give birth to their calves in Baja, before beginning the 10,000-kilometer (6,214-mile) journey back north.
    • Grey whales’ food sources are also a contributing factor to their species range. Grey whales primarily eat species of crustaceans (such as krill, crabs, and shrimp) that live near the coast. These organisms’ fairly shallow habitat limits the species range of the grey whale to generally coastal areas and not the open ocean.
  • Past Species Range Factors
    • The Guardian blog says grey whales used to have a range in the Atlantic Ocean, from ancient Iceland to medieval England. “The last records of grey whales in the Atlantic appear to coincide with the start of modern whaling off the coast of New England,” it says. Ancient and modern whaling may have contributed to the loss of grey whales’ Atlantic species range.
  • Changes in Ranges
    • Scientists are surprised and stumped by the Namibian whale’s appearance. Only one other grey whale has been spotted in the Atlantic—that whale migrated to the eastern Mediterranean in 2010. More shocking still is the fact that the whale is in the Southern Hemisphere—a behavior that has never, ever been recorded.
      • Global warming, the current period of climate change, has led to the Northwest Passage being partially free of sea ice all year. Some scientists think the whale accidentally or intentionally took advantage of the Northwest Passage and moved on to different warm waters last autumn.
      • Grey whales used to inhabit the Atlantic, either as a distinct population or as part of a migration route. This grey whale could have followed an ancient migration path using environmental cues (such as climate), instinct, and internal cues (such as the amount of fat stored in its body).
      • The North American population of grey whales, once nearly driven to extinction, has recovered significantly. The whale may be a “scout” searching for new territory. (This is unlikely.)
• Although the Namibian whale is not following a normal migration pattern, it is possible to make hypotheses about its movement. Read our activity “Many Moves of Migration,” in which different animal migration patterns are described. This worksheet describes eight basic migration patterns. Do students think the wayward grey whale has followed any of these patterns?
  • Sure!
    • latitudinal migration. The whale has probably migrated south, from Arctic feeding grounds. There is also a (slim) possibility that the whale has migrated north, after swimming the entire west coast of the Americas and rounding Cape Horn into the Atlantic.
    • irruptive migration. Irruptive migration is defined as “the movement of animals that is not seasonally or geographically predictable.” This migration is entirely irruptive!
• Where do students think the wayward whale will go next? What environmental and internal cues do students think will influence its migration? (Most North American grey whales are already well on their way to Arctic feeding grounds by this point.)
  • This blog post offers a map with two possible routes the whale may have taken to Namibia. Using the drawing and marker tools on our MapMaker Interactive, ask students to plot where they think the whale came from, and where they think it’s going. (Namibia is in southwest Africa, just north of South Africa. Specifically, the whale was spotted in Walvis Bay, just north of the Tropic of Capricorn.)
    • Will it turn around and head to the North Atlantic?
    • Will it follow its cousin and enter the Mediterranean?
    • Will it try its luck in the turbulent (but nutrient-rich) waters around Antarctica?
    • Will it navigate westward, across the Atlantic?
    • Will it dare to round the Cape of Good Hope and enter the warm waters of the Indian Ocean?
    • Will we all look back on this as a message—so long, and thanks for all the crustaceans?

Thanks to our favorite Spanish teacher, Mrs. Hoogendyk, for the heads-up on this current-event connection! Muchas gracias!