The musk ox herd in White Falcon, White Wolf gets a lucky break when the pack of Arctic wolves chooses to go after other prey that’s easier to catch. But these hairy powerhouses face a great number of dangers in their Arctic home.

Contrary to their name and appearance, musk ox have no true musk glands and are not oxen.  They are more closely related to sheep and goats than the buffalo they more closely resemble. But it’s hard to tell with all that hair. Perfectly adapted to their Arctic habitat, musk ox have a winter coat that is eight times warmer than sheep’s wool. A layer of fine underwool is paired with their long, continuously growing skirt of guard hairs, which can reach the ground in older individuals. The only part of their body that is not covered in warm wool is a small strip of flesh between their nostrils and their lips. Other Arctic adaptations include short legs and a high body-fat content. These traits clearly work well for them, as musk ox have remained relatively unchanged and have successfully inhabited Arctic regions for over 40,000 years. And unlike their former neighbors, the wooly mammoths, musk oxen were able to survive the last ice age without being hunted to extinction by prehistoric peoples. In fact, musk oxen are the only large terrestrial mammal that has inhabited the Arctic continuously for the last 10,000 years.

But the traits that help the musk ox stay warm and survive the Arctic winter come with a price—the risk of overheating. Because of their thick fur, high fat content, and stocky legs, musk ox can only run short distances. Their only sweat glands are located on their back hooves. So, to protect themselves when faced with attacks by polar bears or wolves, musk ox form a circle around their young, with their rumps pointed in and their large horns facing the enemy. Musk ox have been known to maul–and even kill–wolves with their horns.

Wolves aren’t the only threat to young musk ox. For the first year of their life, offspring are dependant on their mothers for both food and warmth. Having not yet grown their full coats or put on the extra weight adults have to keep them warm, young musk ox hide beneath their mothers’ skirts to escape the elements.  Starvation is another winter threat. Musk ox eat almost any vegetation during the summer, including grasses, leafy plants, mosses, herbs, and shrubs. During the winter, when a blanket of snow covers everything, musk ox must dig to uncover frozen tundra grasses using their hooves and horns. At the onset of winter, herds migrate to higher altitudes where the roaring winds help to uncover buried food. The musk ox have no choice but to eat what they can find: Arctic willows, dwarf birch, lichen, roots, and any other vegetation that might lie beneath the icy landscape. This winter diet has very little nutritional value, so it is important for every member of the herd, especially younger individuals, to take advantage of the abundant vegetation during the summer.

Winters are long and dark, and the herd huddles together for warmth. The movement of the herd also helps loosen surface snow, making food more easily accessible, especially for young. If the calves can make it through their first winter, they have a good chance of living a long life. Some individuals live more than 20 years. Others may not be so lucky. Climate change poses a major threat to musk ox, as warming winters and unstable weather patterns bring on bouts of freezing rain that leave impenetrable layers of ice over the winter vegetation musk ox depend on. Unable to access food, many musk ox slowly starve to death. The Large Animal Research Station in Fairbanks, Alaska is hoping their conservation efforts, combined with research from the field, can make a difference in the continued survival of this amazing animal.

To learn more about the musk ox, visit our list of additional web and print resources.

Photo by Tim Bowman, U.S. Fish and Wildlife Service

GRADE LEVELS: 5-8

TIME ALLOTMENT: One or two 45-minute class periods

OVERVIEW:

In this lesson, students will learn about the various attributes of different predators on the African grasslands which make them effective hunters, and about the attributes their prey have developed to help them survive the predators’ attacks. The development of both sets of attributes will be presented as part of natural selection—a process which takes varied forms (and produces varied results) in the earth’s different ecosystems.

In the Introductory Activity, students will use an online interactive to familiarize themselves with the physical attributes of the cheetah which make it such an effective predator. In the Learning Activities, students explore the cheetah’s use of these attributes in pursuit of its equally well-adapted prey—the gazelle—through video from the “Hunters and Herds” episode of the PBS series NATURE, which also discusses the similar contest between lions and wildebeests. The Culminating Activity challenges students to research, compare, and contrast predator/prey relationships in earth’s different ecosystems, and present their findings to the class.

This lesson is intended for use during study on natural selection and adaptations, or a unit on the food chain/web.

SUBJECT MATTER: Science, Biology

LEARNING OBJECTIVES:

Students will be able to:

• Identify the attributes of different predators which contribute to their effectiveness as predators
• Identify the attributes of different prey animals which contribute to their ability to elude predators
• Discuss how the attributes of both predator and prey animals have developed in a process of natural selection
• Compare and contrast predator/prey relationships from different ecosystems around the world.

STANDARDS:

National Science Education Standards

Life Science

Content Standard C

As a result of their activities in grades 5-8, all students should develop understanding of:

1. Structure and function in living systems
2. Reproduction and heredity
3. Regulation and behavior
4. Populations and ecosystems
5. Diversity and adaptations of organisms

MEDIA COMPONENTS:

Video: NATURE: “Moments of Impact– Hunters & Herds”

Clip #1 “Cheetah vs. Gazelle”

An animation-enhanced comparison of the strengths and weaknesses of this predator and prey pair.

Clip #2 “Lion vs. Wildebeest”

An animation-enhanced comparison of the strengths and weaknesses of this predator and prey pair.

Websites:

“Toki’s Survival Challenge”

An interactive in which a cheetah hunts its prey on the African savannah. From the PBS NATURE web site.

“Anatomy of a Cheetah”

A simple interactive highlighting the primary physical attributes of the cheetah as a predator.

MATERIALS:

For the class:

• 1 computer w/ internet connection and projector

For each group of 3-5 students:

• 1 computer w/ internet connection

PREP FOR TEACHERS:

Prior to teaching this lesson, you will need to:

Preview all of the video segments and websites used in the lesson.

Download the video segments used in the lesson to your classroom computer, or prepare to watch them using your classroom’s internet connection.

Bookmark the website used in the lesson on each computer in your classroom. Using a social bookmarking tool such as del.icio.us or diigo (or an online bookmarking utility such as portaportal) will allow you to organize all the links in a central location.

Next: Proceed to Activities.

Excerpts from the NATURE episode, “Moments of Impact: Hunters and Herds”

Cheetah vs. Gazelle
(View full post to see video)

Lion vs. Wildebeest
(View full post to see video)

Downloadable QuickTime versions of the video segments:
(Note: To download a video, right click on the video title and click “Save Link As…’ or “Save Target As…”. On a Mac, press the CTRL key and simultaneously click the mouse, then save the link.)

Video Clips

1.“Cheetah vs. Gazelle”

2.“Lion vs. Wildebeest”

Blue Wildebeest (Connochaetes taurinus)

• Type: Mammal
• Family: Bovinae
• Habitat: Savanna
• Location: South and east Africa
• Diet: Grasses
• Average lifespan in the wild: Up to 20 years
• Size: Body and head 5.6-8 ft (1.70-2.40 m); shoulder height 3.8-4.8 ft (1.15-1.45 m)
• Weight: 260-594 lbs (118-270 kg)

Blue wildebeests exist in a variety of colors, despite their name. There are gray, brown, light, and dark wildebeests, but all have a black mane and tail, short hair, a beard, and dark vertical bands on their neck and shoulders. They have a small hump above their forelimbs, and their profile is slightly sloped. Both sexes of blue wildebeest have horns that grow outward to the side and curve slightly inward at the top. The horns do not have ridges, and can grow up to 1.3 feet long in females and 2.7 feet long in males.

Females and their young form herds of anywhere from 10 to 1,000 individuals. Young males form bachelor groups, but most adult males are solitary and territorial. Males use their horns in shoving matches and disputes over territory. Only males with territory have access to breeding females. During the dry season, divisions between groups break down and massive migratory herds form. They follow rain storms in search of sprouting grasses, their preferred food. During these migrations, wildebeests traverse much of the Serengeti and, though they do not move as a single unit, over 1.8 million individuals move towards wetter areas. Zebras and Thompson’s gazelles also follow a similar migratory path, and travel alongside wildebeest herds. Zebras and wildebeests prefer the same type of grass, but eat different parts of the plant, which means they coexist well together. Zebras also have superior vision and hearing, which wildebeests benefit from. Young wildebeests often watch zebras for signs of alarm.

Blue wildebeests give birth to one calf at a time during a synchronized birthing season in February. A calf can stand on its own six minutes after birth. It is important that offspring be able to keep up and follow the mother closely, as young are the most vulnerable members of the herd. Lions, spotted hyenas, leopards, African wild dogs, and cheetahs all prey on young wildebeests. Adult wildebeests can flee from predators at over 50 miles per hour.

Blue wildebeests typically drink two times per day, and thus access to watering sites is crucial. They forage most actively in the morning and the evening, and rest during the hottest parts of the day. Since wildebeests are so reliant on seasonal rain patterns, global warming and climate change could severely disrupt or damage herds.

Did you know: More than 500,000 wildebeest calves are born over a 2 to 3 week period during the synchronized birthing season in February.

Photo by Hans Hillewaert, Creative Commons license.