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Answers from the Gray Whale Expert
Spring 2011

Special thanks to Kim Shelden for providing her time and expertise in responding to your questions about gray whales! Look for answers to questions like these:

  • Do the moms make the babies leave them, or do the babies want to leave?
  • Are whales afraid of anything in the ocean?
  • If the arctic ice all melts, what will the gray whales do?

Teachers: You can use today's Answers from the Expert, along with those from previous years, in these activities suggested in "Learning from Experts."


Kim Shelden
Marine Biologist

Questions and Answers

From: Livermore, California

Q: Do the moms make the babies leave them, or do the babies want to leave?

A: Once gray whale babies are able to find food and feed on their own, they rely less and less on their mom’s milk. Gray whale calves stay with their moms for a long time migrating from California and Mexico waters where they were born to the northern feeding areas around Alaska. Young whales may continue to follow their mothers even after they no longer need milk. We see this in other dolphin and whale species, such as killer whales. But we also see groups of young whales in other species, such as sperm whales and beluga whales, that go off on their own (though they can usually hear each other over long distances). We don’t yet know the family dynamics of gray whales.

Q: Do you think they know each other if they meet up?

A: We know in other dolphin species that they do recognize family members. I would think that gray whales would too. Calves travel with their moms for a long time, from summer nursing areas to winter feeding areas, and like other whales and dolphins these calves when they are older may return to the same areas their moms took them to as calves.

Q: The observation reports say dolphins mix in with whales a lot and whales must like it. Are whales afraid of anything in the ocean?

A: As far as other creatures in the ocean I would say killer whales, and possibly sharks. When killer whales are in the area we see gray whales do a behavior called “snorkeling” when the whale only surfaces enough to reveal it’s blowhole to breathe. Sometimes a gray whale mom with calf will migrate this way and stay very close to shore. It may be one way to protect her calf from detection. Also by gliding slowly just below the surface, the mom is able to pull her calf along in her wake and the calf is better able to keep up with mom. When killer whales do attack a calf, some mothers try to protect their calves by lifting them up out of the water using their head or back to support them. Others try to get their calves into shallow water where the killer whales may not follow. Gray whales also roll belly up and slash back and forth with their tails when they feel threatened.

Q: What do you think humans can learn from gray whales?

A: There is so much we still do not know or understand about these amazing animals. But as scientists we continue to study these animals, to learn where they live, how they survive in their changing environment, and how we can best protect them so future generations can continue to see them in the wild.

From: San Rafael, California

Q: What factors might trigger a low number of gray whale births?

A: The number of calves seen each year at the different research stations can vary considerably. In some years we see many calves off central California during the southbound migration, usually when sea surface temperatures have been unusually warm during the winter months. At the same time, other researchers studying calves in the Mexico lagoons tend to see lower numbers and these scientists think it may be because it is too warm in the lagoons. It may be that during warm years, mothers that give birth while traveling south do not go all the way to the lagoons. Overall, calf sightings have increased across the past five decades at many of the California counting stations, in part due to the increased size of the gray whale population, but the increase may also be related to environmental changes that may be causing gray whales to delay their migration. We have seen a one-week delay in the migration since the late 1970s at the central California counting station. Assuming that the timing when females give birth (parturition) has not changed, the delay has meant that calving has been occurring farther north.

Q: If the arctic ice all melts, what will the gray whales do?

A: Gray whales tend to be more pagophobic (which means ice-fearing) rather than pagophilic (ice-loving) so they will probably extend their range into northern ice-free waters. It may mean that they begin to compete for food with bowhead whales that can live year-round in ice-covered seas. Without ice in the way, gray whales will have new areas open up to them where they weren’t able to feed before. Gray whales are wonderfully opportunistic when it comes to what they eat. They skim feed along the surface of the water with mouths wide open eating copepods. They also eat bottom dwelling animals such as marine worms and crustaceans (primarily amphipods), by swimming down to the bottom, rolling on their sides, and sucking the mud into their mouths.


Q: What kinds of data are alerting scientists to obstacles/challenges gray whales face today?

A: A number of scientists are studying how climate change may affect gray whales. They are studying changes in sea ice, temperature, water circulation and other physical environmental variables and how these changes affect zooplankton that whales feed on. It is hoped that by studying these changes, scientists will also learn how well whales can adapt.

From: Pleasanton, California

Q: What are the biggest challenges gray whales face today?

A: Gray whales have made an amazing recovery from the time of commercial whaling. We still have so much to learn about them but unfortunately funding is hard to come by. The greatest threats still continue to be anthropogenic, that is human caused, and these are of concern for all whales and dolphins. It is very important to study the effects of pollution, ship traffic, fishing, and oil and gas development, just to name a few.

Q: What kinds of technology is used to help scientists study gray whales?

A: Some scientists use small planes or helicopters to fly to remote areas to learn where the whales are and to count how many are there. They fly along tracklines and when they encounter a whale they circle and count how many they see. Others count whales at sites along the shore where they use binoculars and theodolites (a surveying tool) to get information on the location of the animal, which direction it is traveling, and how many are in the group. Scientists also track gray whales by the sounds the whales make. These scientists use underwater recording devices that are moored to buoys or dropped from airplanes or ships. When they hear a whale they follow the sounds it makes (known as whale calls) until they see the whale. Scientists have also put satellite tags on gray whales. These tags send a location signal to satellites that are circling the earth and let the scientists know where the whale is traveling to and some tags even collect information on how deep the whale is diving.

Q: What are the most important things law-makers and citizens need to know in order to protect gray whales?

A: It is hard to know how climate change will affect all of these species - it is one of the biggest issues looming for all marine mammals. It is possible that reductions in sea ice will allow these species to travel farther north - but with reduced sea ice we are likely to see more oil exploration and shipping. I think that is why it is so important for us to keep funding long time series studying abundance and distribution - we have studied the southbound migration of gray whales from a site in central California since 1967. With such long lived species, long term monitoring is essential for detecting signs of recovery or signs of endangerment. I think the biggest hurdle we face is having adequate funding to continue these studies and to initiate new studies. Without the science it is very hard to set policy and to manage these populations.

From: San Diego, California

Q: What are the hardest things about gray whale study/research/tracking?

A: Each time we learn something about these whales it opens up all kinds of new questions about them. The hardest part about studying any animal that lives its entire life in the ocean is that it spends so much of its life below the surface where we can’t observe it.

Q: I want to be a whale researcher. What advice do you have for me?

A: It’s funny really, I always expected to work in the area of coastal oceanography and I never in the world thought I would be studying marine mammals. I just happened to end up here by chance. Many people I work with come from all kinds of academic backgrounds including computer science, math, genetics, chemistry, oceanography and environmental science. To see if you really want to have a job like mine, there are a number of volunteer and internship positions with my agency as well as local aquariums and stranding response centers.

Q: : What have been the most surprising things or the biggest rewards about being a gray whale researcher?

A: I would say it would be that we are constantly learning new things about these whales. For instance, they surprise us by going places we never imagined they would go. One whale migrated from Russia to the United States and another found its way into the Atlantic Ocean where gray whales haven’t been seen for centuries.

From: Texas

Q: Do the gray whales only reside in the Pacific or do they migrate to other oceans on the globe?

A: We were very surprised when a gray whale showed up in the Atlantic Ocean in 2010. Gray whales haven’t been seen there for centuries. We are not sure how often this happens or if this particular gray whale ever made it back to the Pacific.

Q: What impact are we seeing on the whale population in the Pacific Ocean as a result of the Japan nuclear disaster?

A: According to scientists who study radiation effects, effects on marine life should be minimal if the plume is blown over the ocean. These scientists have found that radioactive isotopes are most dangerous when animals' bodies absorb them, thinking they're something else. For instance, cesium-137 mimics potassium and is absorbed by muscles, while strontium-90 mimics calcium and is taken up by bones. Since ocean water is full of potassium and calcium in the form of salts, this lowers the chance of an animal's body taking up radioactive particles by mistake.

Q: How has the Gray Whale food supply been affected with the recent radiation levels from the nuclear meltdown in northern Japan?

A: Similar to the question about how the whales might be affected by radiation, scientists believe since the Pacific is so massive, radioactivity will be diluted to levels far too low to be toxic to aquatic life such as the zooplankton gray whales feed on. A much bigger concern is the plume blowing over land and contaminating plant life or the freshwater supply, which would affect animals (including humans) further up the food chain.

From: Las Cruces, New Mexico

Q: : I would like to know if there have been anymore sightings of the "Mystery Gray Whale" that was seen off the Israeli and Spanish coasts last year [2010] — the last sighting I've read about was in June, 2010.

A: I’m afraid there aren’t any more recent sightings of this wayward whale. This is a short video clip by the Israel Marine Mammal Research & Assistance Center.

Q: What may have happened since then to this whale?

A: We hope that it found its way back to the Pacific Ocean and rejoined gray whale populations there.

APRIL, 2011: Scientific Paper Released
There had not been any more sightings of this wayward whale, first sighted on 8 May 2010, off the Israeli Mediterranean shore and 22 days later in Spanish Mediterranean waters. However, just this week a scientific paper was released about this wandering whale. The authors believe it was from the eastern Pacific stock (those that are seen along California). They believe this whale most likely followed the northern coast of Eurasia, or made its way through the Northwest Passage. The paper considers the the potential impacts from global climate change. Some wonder: Will gray whales re-colonize the North Atlantic as the shrinking of the Arctic Sea ice, due to climate change, reduce the ice barriers between oceans?

The paper:

Aviad P. Scheinin, Dan Kerem, Colin D. MacLeod, Manel Gazo, Carla A. Chicote and Manuel Castellote (2011). Gray whale (Eschrichtius robustus) in the Mediterranean Sea: anomalous event or early sign of climate-driven distribution change? Marine Biodiversity Records, 4, e28 Abstract