Gray
Whale Migration
Fall: October, November, December
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Gray
Whale Migration Route
(Click on map for more) |
Heading South
It's prime
time again for one of the greatest shows in the marine world: the California
gray whale's migration from frigid arctic feeding grounds to Mexico's
balmy birthing lagoons. Each October or November, gray whales begin
plowing
south by the hundreds from their summer feeding grounds between Alaska
and Siberia. These 40-ton giants complete a 5,000 to 6,000-mile journey
south to their winter mating and birthing grounds in an average of 55
days by swimming nonstop. In December they begin arriving in the four
calving and mating lagoons of Mexico's Baja California coast. (Click
on the map dots to read more about each lagoon.) They gather by the
thousands
in these sheltered bays and lagoons to court and mate. Many females give
birth to calves conceived in these lagoons the winter before, after
a
gestation period of 13 months. (Around the age of five years, mature
female gray whales usually start having a calf every two years of their
long
lives.)
California
gray whales travel farther than any other migratory mammal on Earth.
Following
a path that's usually within a few miles of shore, they swim just below
the water surface. During the fall and again in spring, people who
enjoy
whales make their own journeys to the Pacific Coast; they hope for a
look at these gentle giants passing by. Thanks to their nearshore migratory
path, gray whales are seen by more people, in more places, than any
other
type of whale. Get your own up-close look with this video clip!
Lessons
for Fall
- Why
Head South? Does it surprise you that the whales would go all
the way from Alaska to Mexico when they aren't going to give birth?
Why do they go if they're too young to mate? See what two experts
think.
- The
Migration Trail: Any Shut-eye Along the Way?
Do whales rest along the way? How? For many years, scientists were unsure
about this question. Read what naturalist Tom Lewis says about a whale's
rest or sleep.
- Southbound
Babies: Two Scientists Speak
A few babies each year are born during their mother's migration
south—before reaching the warm, sheltered nursery lagoons.
What does this mean for the babies?
- Hitchhikers:
Free Rides on Gray Whales
Imagine carrying a ton of hitchhikers on your back! Gray whales do this
all their lives. Grays are more heavily infested with a greater variety
of parasites and hitchhikers than any other cetacean. Who's riding,
and why?
- Adaptations
That Help Gray Whales Survive
Dissecting a dead whale, a marine biologist could see that it spends
its life in the ocean, lives at least part time in very cold water,
and migrates long distances. How? By understanding how whale bodies
and behaviors are adapted to habitat and food requirements. This
lesson
looks at a gray whale’s body from head to tail to see just
how this marine mammal is perfectly designed for the life it leads.
- Who
Is That Whale? Gray Whale Photo ID Matching
How are those barnacle clusters carried by gray whales of enormous use
to scientists? With circles and arrows on whale photos, Dr.
William Megill teaches you how barnacle clusters identify individual
whales. Test your abilities with Dr. Megill's photo quiz!
- Sink
or Float? Investigating Buoyancy
What makes it possible for animals as heavy as gray whales to easily
float and move in water? These investigations into density and the properties
of salt water can help shed light on that question.
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