Caribou Migration Update: May 8, 2002 Today's Report Includes: Latest from the Arctic Front Off the Top of Your Head- Antlers! Challenge Question #19 Dempster Highway- Roadway to the Arctic Curious Caribou: Challenge Question #20 I See Sea Ice: Challenge Question #21 Caribou as Provider: Discussion of Challenge Question #16 Predictions and Trends: Discussion of Challenge Question #17 Deep Snow = Trouble for Caribou: Discussion of Challenge Question #18 Return of Arctic Trekker, Stephen Kaliowski Year-End Evaluation: Please Share Your Thoughts! Latest from the Arctic Front Caribou Migration Map Click on Map to Enlarge Mosquitoes are looking for fresh blood as springtime arrives in the Dawson City, Yukon. Just as temperatures are fluctuating on the rest of the continent from the 90s to the 30s, so it goes in the Arctic as well. Martin Kienzler sighted his first black bear on April 21. He writes, "The caribou have really slowed down their movements in the last couple of weeks. It's only one month till calving, which is plenty of time, but..." Where are the caribou now? Take a look at the data: Today's Data Off the Top of Your Head- Antlers! Arctic National Wildlife Refuge, June 2001 Amy Gulick Imagine balancing heavy bones on your head and carrying them everywhere you go! Any idea why caribou have such amazing antlers? Antler development is a unique phenomenon of nature. In some species such as moose only males grow antlers whereas in caribou both males and females grow antlers each year. In all cases it is an annual process that separates antlered animals from horned animals that usually grow a set of horns over a lifetime. The bulls can develop spectacular antlers at times exceeding 125 cm (49 in) in length and up to 20 pounds in weight. This growth uses hard-earned energy every year--one can't help but wonder why? Here caribou biologist Doug Urquart describes the seasonal differences between the antlers of males and females: "Antler development is 3-6 months out of phase between the sexes. For example, the male's antlers begin developing in March, grow rapidly from May to July, and are completely hardend and out of velvet by mid-September. Following the rut, antlers are shed in early November by older males, but may be kept until April by some of the younger ones. Female antlers develop from June to September and are out of velvet by late September. The females' antlers are retained throughout the winter. Pregnant females drop their antlers within days of calving. Barren cows shed their antlers before the spring." (Provided courtesy of the Government of the Northwest Territories, Division of Natural Resources.) Challenge Question #19: "For what reasons might female caribou keep their antlers during the winter, while males drop theirs in the fall?" (To respond to this question, please follow the instructions below.) Remember, WHEN something happens often helps explain WHY it happens, so try to think of what kinds of energy that goes into growing antlers and the different ways antlers can be used. Then guess the reasons for the differences Urquart describes. Try This! Make a life-sized pair of caribou antlers and put them on display. Find something that weighs the same as caribou antlers do, and try to balance them on your head. Proportionate to your own weight, calculate how heavy your antlers would be. (Average body weights for Porcupine caribou are: male 130 kg/285 lbs, and female 90 kg/198 lbs.) Dempster Highway- Roadway to the Arctic In all of North America, across the vast wilderness of northern Canada and Alaska, only one year-round public highway crosses the Arctic Circle, the Dempster Highway. The Dempster Highway is located in the Yukon and Northwest Territories. The road starts approximately 25 miles east of Dawson City and continues north northeast 736 km (457 miles) to Inuvik. Take a look at this map of the Dempster Highway. The Dempster drive crosses mountain ranges and alpine tundra. Large winter herds of caribou often can be seen along its way. Travelers view the wildlife-filled marshes of the Mackenzie Delta, and cross the Arctic Circle eventually cross the northern tree line. Hunting, fur trading, gold fever and oil exploration are some of the nt historical events that lead to the development of this highway. Read about the history of this Arctic roadway: History of the Dempster Highway Curious Caribou Courtesy Steven Kalinowski Arctic Reflections Caribou are curious animals. They will traverse all kinds of rugged country on their migrations- slogging through bogs, fording swift rivers, swimming large lakes and toiling over mountain passes. But according to caribou biologist Doug Urquhart, they will not step across a ribbon of material stretched along the ground. Scandinavian herders used to direct reindeer to go where they wanted. They would lay out long dark strips of rope in a line where they wanted the reindeer to go and the whole herd would turn and follow the little ribbons wherever they led. Gwitch'in and Inuit would build driftwood and antler fences in a long line to direct caribou along a route. Courtesy the Satellite Collar Project The winter migration range and the Dempster Highway often come together. Take a look at this map showing 2001 sightings of our caribou. How many places along the highway do you see satellite collared caribou sighted? With this in mind imagine what impact a 457 mile road might have on the caribou! Challenge Question #20: "What effects might the Dempster Highway have on caribou behavior and travel?" (To respond to this question, please follow the instructions below.) I See Sea Ice Have you ever looked at a map of the earth looking down at the Arctic and North Pole? The National Geographic Atlas shows a large expanse of blue water labeled, Arctic Ocean. It is kind of an optical illusion because the map would lead us to think that the Arctic Ocean is open water. We know that most of this should be ice. Courtesy of National Snow and Ice Data Center View today's map of the "Cryosphere" (snow and ice coverage) in the Arctic provided by the National Snow and Ice Data Center . Notice the white(snow) and turquoise (ice) colors on the map. During most winters, the Actic Ocean is frozen right to the coast of northern Alaska, and the ice pack extends southward through the Bering Straits to the vicinity of St. Matthew Island. However, even in mid-winter the ice pack is continually being broken by winds and ocean currents, which form the large leads visible in the satellite images. During late May or early June, the ice in the Beaufort Sea begins to melt, first forming a band of open water along the coast. This band of water may open or close as wind pushes the ice floes either toward or away from shore. During summer, the area of open water increases and may be anywhere from a few miles to 200 miles wide. Then during September, the ice pack again begins to grow, and by mid October the ice has usually spread to cover the Beaufort Sea again. Sea ice typically covers about 14 to 16 million square kilometers in late winter in the Arctic. This large frozen ice shelf will typically decrease to approximately seven to nine million square kilometers in the Arctic. Challenge Question #21: "If the ice covers 16 million square kilometers in late winter and 9 million square km in summer, what percent of the ice melts away with the change of the season? Do some math to calculate your answer." (To respond to this question, please follow the instructions below.) Caribou as Provider: Discussion of Challenge Question #16 Traditionally the caribou were essential for the survival of the Northern Indian people. We read about some of the traditional tools fashioned from caribou bone and antler. Now you responded with items we now use that could be made from antler or bone. Here is a sampling: forks spoons, knives, bowls cane handles cups jewelry Predictions and Trends: Discussion of Challenge Question #17 Keeping track of a wild population is important to scientists. Since 1973, the highest population count was in 1989. The lowest was eleven years earlier, in 1977. The difference between high and low was 77,000 caribou. Calculating the average population from 11 censuses and you get 136,000. Since the herd was first counted using the current method, the population has fluctuated greatly. What makes the herd change sizes every year? Deep Snow = Trouble for Caribou: Discussion of Challenge Question #18 In addition to trouble getting access to food in deep and crusty snow conditions, the caribou face difficult times when snow and calving occur simultaneously. Dr. Arthur helps us understand the situation, "During 2000, deep snow throughout the winter range that persisted into early June slowed migration of the herd, so that most calves were born in Canada, and many cows had not yet reached the coastal plain at the time births occurred. The herd then followed the rapidly-melting snow westward and most had reached the traditional calving area by mid-June. By that time, the area was snow-free." Deep snow in winter of 2000 delayed migration and calves were born outside the coastal plain Dr. Arthur sent this map to show the movement of the herd from June 10-30, 2000. We asked you to think about how this late snowstorm might effect calving and here is what you replied: "Since Trudy died of the cold, a lot of other caribou might die as well. When the caribou went to the foothills to get away from the storm, they didn't know the storm would be heading their way. This will be a problem to the new born caribou. Most of the baby caribou will most likely die. Since Trudy died of the cold, a lot of other caribou might die as well." Thanks to Iselin Middle School 7th Graders, Bridgette, Justin, Jackie and Kawan! Return of Arctic Trekker, Stephen Kaliowski Steven Kalinowski made a successful trek across the Arctic National Wildlife Refuge (ANWR) with time to spare. He called the Journey North headquarters to announce his safe arrival in Kaktovik on April 25, 5 days earlier than planned! Just after leaving the Huluhar River but before crossing the coastal plain he was hit by a huge blizzard. Lucky for him, timing was everything. Experiencing a blizzard on the coastal plain where winds can build up for miles without anything to stop them would be extremely dangerous. Porcupine Caribou- April 2002 Courtesy Steven Kalinowski Arctic Reflections Kalinowski met up with about 100 caribou along his route who "were not at all interested in getting close." How cold was it? His reply was simply, "The cold was tolerable except for one night. I couldn't sleep in my arctic sleeping bag, so I know the temperature was somewhere between 30 and 40 degrees below zero." Read all about his trip and share some of his pictures on his Web site: Arctic Reflections Year-End Evaluation: Please Share Your Thoughts! Please take a few minutes to share your suggestions and comments in our Year-End Evaluation Form below. The information you provide at the end of each year is the single most important tool used to guide our planning. Journey North Year End Evaluation Please share your thoughts Year-End Evaluation: Please Share Your Thoughts! 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-caribou@learner.org 2. In the Subject Line of your message write: Challenge Question #19 (or #20 or #21). 3. In the body of EACH message, give your answer to ONE of the questions above. The Next Caribou Migration Update Will Be Posted on May 22, 2002 Copyright 2002 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form