Answers from the Gray Whale Expert
Included in this Message:
Scott Young P.S.
Q: Why do the gray whales swim all the way down to Mexico to have their babies? Why don’t they stay were they are because they have enough fat to keep them warm.
A: The moms do have plenty of fat to keep them warm, but the babies don't! When gray whales are born they have practically no fat on their bodies. In fact their skin hangs in folds along their bodies and they look like little tadpoles. So it is much better for these babies to be born in warmer waters away from the cold of the Arctic where mom can nurse them until they get nice and fat for the return trip to Alaska. Baby gray whales gain weight very quickly and grow about 9 feet by the time they are weaned .
Q: How much fat does the gray whale really have?
A. The amount of fat varies greatly, depending on the time of year and age of the whale. When the whales are feeding off Alaska, their body fat increases. When they migrate, they burn fat and lose weight. Body fat is different from blubber, and gray whales are losing mostly body fat when lose weight. Some blubber thickness is also lost during migration, but it is not very much. Blubber thickness can range from 9 cm to 20 cm depending on the age of the whale.
Q: Why do gray whales have so much fat when they swim around a lot? Wouldn’t they burn off a lot of that fat?
A: Gray whales are constantly eating while they summer up north off Alaska. During this time they gain weight by eating the large zooplankton found in the cold waters off Alaska. During the summer feeding season they are not traveling the long distances they do when they migrate. During the migration south to Mexico then back north to Alaska, gray whales feed opportunistically (only when and where the find food) but they are expending much more energy swimming during the migration. Some whales become quite skinny before they return to Alaska.
West Ottawa Public School
Q: Do whales migrate to the exact same area each year and how can we be certain?
A: One way researchers can tell if whales migrate to the same areas is by photographing the whales and looking for unique marks on their bodies. This is called photo-identification. This technique has been used to track humpback whales, killer whales, bowhead whales, and many other species. In fact, scientists using photographs found that about 70% of the gray whales found off Sakhalin Island, Russia, return to the same feeding areas year after year. Scientists call this "seasonal site fidelity."
Q: Can we define the "gps" system they use to navigate?
A: This is a great question, and one that scientists continue to investigate. Some researchers speculate that gray whales use landmarks, keeping the coast in view most of their migration — but no one really knows how any of these whales navigate the oceans.
What effect will global warming have on these animals?
West Tisbury School
Q: Our multiage class (6-8 year olds) have been studying the whaling history of Martha's Vineyard and whales. They want to know: Did the whalers ever hunt gray whales for oil? Were gray whales hunted for anything?
A: Yes! Gray whales were hunted so extensively that they were put on the Endangered Species list. The following description can be found in a book by Dale Rice and Allen Wolman (1971) called The Life History and Ecology of the Gray Whale, (Eschrichtius robustus).
Do they often follow boats and spyhop on people? How do they play? How
do they react to people?
How high is their spout, how long does it last?
From Minneapolis, Minnesota
What are some kinds of current gray whale research that you know of?
How to Use FAQ's About Journey North Species
Since 1995, experts have contributed answers to students' questions about each Journey North species. These questions and answers are archived in our FAQ's (Frequently Asked Questions) section. You can use today's Answers from the Expert above, along with those from previous years, in the activities suggested in the lesson, "FAQ's About Journey North Species."