Gray Whale Migration Update: March 19, 2003
Today's Report Includes:
- Plowing North: Migration Highlights Along the Coast
- Big News in Laguna Ojo de Liebre! Pure White Whale Calf
- Albino Calf: Challenge Question #9
- Swimming in Order
- Counting Calves With Wayne Perryman
- A Good Year for Calves? Link to Lesson
- Hitchhikers: Mystery Photo Identified, Link to Lesson
- Gray Whale Adaptations: Discussion of Challenge Questions #7, #8
- Sleep: Discussion of Challenge Question #6 and Try This! (Activity)
- Get Ready! Ask the Expert Opens March 21
- Try This! Graphing to See Answers
- What?s This? Looking Ahead
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Gray Whale Migration Route |
Eschrichtius robustus is parading all along the Pacific coast, but none have yet reached Alaska. Look in the full report (link below) for the answers to questions, but here are the highlights along the coast:
- In Tofino and Ucluelet, British Columbia, Jamie?s Whaling Station reports typical numbers for this time of year. How did last week?s weather affect whale watching there?
- In Westport, Washington, Capt. Geoff Grillo says, "Pretty tough whale watching weather the last week." What did he mean?
- In Waldport, Oregon, gray whale migration is nearing a peak. Volunteers from Whale Watching Spoken Here will be stationed at 29 locations on or near the Oregon Coast from March 22-March 29. Next time we hope to have some results of their count. What tips do they have for whale watchers?
- In California?s Channel Islands National Marine Sanctuary, volunteer naturalists reported 118 sightings of 263 whales, only three of which were calves. Read how the whales entertained them, and (before you read the full report) see if you can answer questions asked of the naturalists: How many calves does the typical Gray have in a lifetime? Will a mother always recognize her young? Or once a calf ventures out on its own, does it become just another gray to the mother?
- At the ACS Census on Point Vicenta, CA, volunteers haven?t seen a calf since the first two on Feb. 28 and March 1. But on March 7 the census passed 1000 total whales seen this season! Mike and Winston ask: How many more whales do the ACS spotters need to see to pass the 1994-94 season? How many more whales to pass the 1990-91 season? (You can figure it out with facts in the full report.)
See more fun details in the full report here:
Then read on to find out more about the whales who aren?t yet migrating, or those
just starting out on the long journey north!
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Keith Jones sent this close up of a baby gray whale, taken March 3, 2003. Click to enlarge for a fantastic close up! Keith hopes to also send us a photo of the albino baby. |
Whalewatching Tour Guide Keith Jones sends this surprising report: "The big news is the baby albino that was spotted for the first time about February 15th. He was seen first in Guerrero Negro Lagoon, and the next day inside the mouth of Laguna Ojo de Liebre. Two days later I saw him at the very back inside observation area. Then I saw him again on the 20th or 22nd at the mouth of the lagoon once more. Then he was back to the inside area on the 23rd--always with his mother, of course. Mother was very shy and always swam away when boats approached. We never got close enough to confirm that the baby did in fact have a pink eye. He was pure white, however; I can vouch for that."
Pigments are the chemicals in our bodies that give us our colors. When a bird or other animal makes no pigments, the condition is called albinism, and the animal is called an albino. What do you think the lack of pigments might mean for this baby gray whale? Gray whales are probably gray for a reason. In what ways might skin pigments be important to gray whales? To help your thinking, we suggest reading about albinism in robins for a start:
Then come back and answer:
Challenge Question #9:
"List some of the special problems this albino gray whale might face in its life. Think about its vision, its interactions with other whales, and its visibility to predators. Do you think it would be easier or harder for a gray whale to be "different" from its family and neighbors than for a human to be "different"?
(To respond
to this question, please follow the instructions below.)
Swimming in Order
When these cows and calves start their journey north, other whale counters eagerly await their appearance along the migration trail. As our friends Mike and Winston remind us: The northbound whales we start seeing first are usually single mature females (possibly pregnant). Next we begin to see mature males, followed by immature males and females. Last, we see the mothers with their new calves." Why do you think the moms and calves come last?
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Wayne Perryman's Census Site at Point Piedras Blancas, CA |
For the 10th year in a row, Wayne Perryman has towed an Airstream trailer onto the pad, set up the binoculars and welcomed his watch team at Point Piedras Blancas, CA (35.40N, 121.17 W). Wayne is a biologist at NOAA's Southwest Science Center and a government specialist on calf birth rates. One of his duties is to count the mother/calf pairs when they start the journey north. Mr. Perryman and a few partners will watch for cow/calf pairs 12 hours a day, 6 days a week until early June. March 17 was the first day of watches. "We spent the weekend getting the site set up, mounting the 25 power binoculars, and building a wind shield to keep those cold winds out of the north off our backs. Lots of adults and juveniles passing at this time. No calves yet, but we are watching." (See photo in Web report.)
Wayne?s annual cow/calf census is an important study. He says: "The work that I am doing is directed at monitoring calf production for the eastern Pacific population of gray whales. This population was removed from the List of Endangered Species in 1994 and one of the agreements associated with that decision was to monitor reproduction in gray whales over a 5-year period. But because we have seen much wider fluctuations in the number of calves than we expected, we have extended the study." In 2001, the total calves counted stood at 66 on May 15, the lowest count by that date in the 8 years of surveys from Piedras Blancas. In 1996-1998 total calves for the season were closer to 500. What will the count be this year?
A Good Year for Calves?
What is the outlook for gray whale calf production in 2003? We'll find out as Wayne Perryman sends us his reports in the coming weeks. So far, Wayne says: "The seasonal ice that covers the gray whale feeding grounds backed off early again this year and we are predicting another good year in calf production. My estimate is for maybe a 10 to 20% increase over last year."
Why is calf production lower in some years than in others? What reasons might account for changes in numbers of calves born each year? What things might result in a low number of births? Why did Wayne comment on the ice that covers the whales? arctic feeding grounds? You?ll find out here, as Wayne helps you practice thinking like a scientist:
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Imagine carrying a load of hitchhikers on your back that can weigh several hundred pounds! Gray whales do this all their lives. Grays are more heavily infested with a greater variety of parasites and hitchhikers than any other cetacean. Some whales carry a ton of barnacles like those in this mystery photo (see Web) from last week. Who's riding on whales, and why? Why do gray whales have more hitchhikers than any other whales? Find out here:
TEACHER TIP: This short nonfiction selection
comes with an accompanying menu of choices from the lesson in our new Reading and
Writing Connections. From that lesson, here?s a suggestion to set the stage for reading.
Below it you?ll find an Instructional Strategy (student activity) to do during the
first reading:
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Gray Whale Adaptations: Discussion of Challenge Question #7
Last time we asked, "How is slow metabolism a useful adaptation for whales? Why do you think a human?s metabolism is so different from a whale?s?"
Congratulations to Ana and Ronald, Grade 5 at Hamilton Ave. School in Greenwich, CT. for a good answer to the first part! They said, "Their metabolism is very low so they make efficient use of food energy, burning far fewer calories per day per pound of body weight than humans do. The blubber layer is 5 or 6 inches thick to provide insulation against the freezing water. Blubber stores food so whales can eat huge amounts of food when food is abundant, and then survive when and where food is scarce." These students knew the whale?s blubber had to be used up slowly to last a long time.
Low metabolism is useful because whales are ENORMOUS. That means they have a small surface area (which is comparable to how much heat they can lose) compared to their volume. What if they had a rapid metabolic rate? Their body would get extremely hot. Even in the icy waters of the northern ocean whales would not be able to lose heat as fast as their huge bodies produced it unless they lost all their blubber. Also, if whales had a faster metabolic rate, they would need more food AND more oxygen. They'd have to spend most of their lives at the surface. And their huge hearts would have to work very fast to keep oxygen pumping fast enough to keep their entire body working at high speed.
Last time we said that when another species has an adaptation that humans lack, there must be reasons. We asked you why a human?s metabolism is different from a whale?s. If you think about it, we humans have an easy time breathing, and can usually get enough food. We don't have the blubber that whales do; we wear clothing to keep our heat in. We're smaller, with faster heart rates and breathing rates to go with our faster metabolism. The animals with the highest metabolic rate are the tiniest ones--the hummingbirds. They breathe VERY fast, and they must spend virtually all their waking lives feeding.
Discussion of Challenge Question #8
Last time we asked you to answer the question asked by Morris, one of our readers. He wanted to know: "Why can whales live by drinking salt water and humans cannot?"
"Whales can live in salt water because of their powerful kidneys," answered Iselin Middle School students Krishna, Courtney, Rosette, Pamela, Vanessa, Melissa, Matt, Gary, and Tassneem (grade 7A). Chris, Scott, Brian, and Yuandra (Iselin Middle School/grade 7A) said the whales? more powerful kidneys allows them to pump out [filter out] the salt. "If they didn't, the salt would absorb water from the cells and dehydrate them." Good work, all of you! We can tell that you read our pages about gray whale adaptations.
Dr. Dave Rugh, our whale expert, adds these details: "Morris asks a good question, one I'm sure many others have pondered. Not only whales but all marine mammals and sea birds have had to evolve with a high tolerance of salt in the sea water they take in when they eat. Because whale blood is similar to the blood of land mammals (that is, it is not any more salty), their kidneys must excrete (get rid of) the excess salt through urine. Sea water is about three times more salty than animal blood. Humans are not adapted to such high concentrations of salt, so drinking too much salt water can kill us. However, some desert animals, where water conservation is so precious, can tolerate even higher concentrations of salt. Part of the answer to why humans cannot tolerate sea water but whales can is in the economy of evolution. If humans drink fresh water, then why bother having huge kidneys to cleanse the blood of excess salt? Instead, human organs are adapted to approximate the need."
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Do Whales Sleep? |
Last time we asked, "Do whales sleep?" We are proud of all the students who did some good research! Iselin Middle School/grade 7A students Rosette, Pamela, Courtney, Krishna, Yuandra, Brian, and Scott recognize that, being mammals, whales are like humans in a lot of ways. They said, "Sleeping lets your brain and muscles rest for a long journey." Weasley, Trent, Jameel and Zirft said while a whale sleeps, "half of the whale's brain stays active."
Fifth graders Melody, Justin, and Jonathan of Hamilton Avenue School in Greenwich, CT. share these two theories: "Gray whales do sleep with their blowholes exposed to the surface but during their extended migration they don't sleep at all. Instead they swim day and night; this is theory number one. Theory number two is scientists now think that whales do sleep and continue swimming on "autopilot" and they catch up on sleep in the lagoons where they have been observed snoring! Others say whales take short naps ranging from 10-20 minutes. We still don't know exactly if they do or don't sleep."
Hollie (grade 5, Hamilton Avenue School) had this to add: "Two basic methods of sleeping are they either rest quietly in the water, vertically, or horizontally, or sleep while swimming slowly next to another animal. Companionable animals may pair for sleeping while swimming. Although still a matter of discussion. Most researchers feel that in order to breathe, a dolphin or whale must be conscious and alert to recognize that its blowhole is at the surface. Whales must keep part of the brain alert to trigger each breath. Obviously sleeping safely at sea can pose problems, but the marine mammal system had addressed them."
Hooray for these good researchers! Can you believe there?s even more to know about whales and sleep? Check out what teacher and ACS tour guide Tom Lewis says about how scientists study the question of whales and sleep:
Try This! Going
to Sleep
We don't really know what a whale's resting state feels like, but here's a good guess.
A whale's resting state probably feels something like the semi-conscious state we
experience as we begin to fall asleep. Tonight when you go to sleep, try to be aware
of what happens. You may notice that when you're pretty close to being asleep (or
close to being unconscious), you are still aware enough of your surroundings to wake
up completely if you need to.
Get Ready! Ask the Expert Opens March 21
You?ve already been hearing from our expert, Dr. Dave Rugh, in several reports. Now?s your chance to ask him your toughest gray whale questions. Submit them any time between March 21 (not before) and the April 4, 2003 deadline at noon (Central time) or 1 p.m. (Eastern Time).
Try This! Graphing to See Answers
You can keep tabs on the daily gray whale census counts at Point Vicente by visiting the ACS Web site, where the numbers are posted each day:
Last time we asked, "What?s your prediction for the peak week in the northward
migration?" Here are the number of northbound gray whales spotted each day since
February 8:
3, 1, 0, 0, 0, 10, 9, 2, 2, 1, 10, 4, 10, 5, 3, 15, 6, 18, 16, 16, 12, 14, 24, 4,
9, 21, 13, 22, 36, 15, 17, 25, 36, 23, 24, 16, 15, and 14 (on March 17, 2003). Graph
the numbers and look for answers to these questions:
1. What day did the journey north begin in earnest?
2. Do you think we?ve seen the peak week yet? (Keep up your graph by checking the
ACS web site daily.)
3. Can you identify any pulses? (Larger movements followed by a slower period with
lower whale numbers)
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Do you know what this photo (at right) shows? Next time Mike and Winston will tell you more about it. See you then!
How to Respond to Today's Challenge Questions:
IMPORTANT: Answer only ONE question in each e-mail message.
1. Address an e-mail message to: jn-challenge-gwhale@learner.org
2. In the Subject Line of your message write: Challenge Question
#9.
3. In the body of EACH message, give your answer to ONE of the questions above.
The Next Gray Whale Migration Update Will Be Posted on April 2,
2003.
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