NATURE travels around the world to visit some of these fascinating primates. From tiny pygmy marmoset in South America to aggressive baboons of Africa and compassionate toque macaques in Sri Lanka, Clever Monkeys challenges many ideas about what is purely “human.”

Clever Monkeys premieres Sunday, November 9 at 8pm on PBS (check local listings).

To order a copy of Clever Monkeys, please visit the NATURE Shop.

(Click here for a printer-friendly version of this lesson.)

GRADE LEVEL: 9-12

TIME ALLOTMENT: Three 45-minute class periods

OVERVIEW: The traditional view of animal behavior is that it is driven by inherited, innate instincts, but recent scientific research is revealing a larger role for complex cognitive processes among many species. The lesson will explore some of the more commonly accepted indicators of animal intelligence as demonstrated by the most brainy of all birds-the raven.

Students will first explore a series of science Web sites to compile a list of certain animal behaviors and abilities that indicate higher intelligence. They will then find and analyze examples of these behaviors and abilities as demonstrated by ravens in selected clips from the NATURE episode “Ravens.” Based on what they learn, students will then work in groups to create a theoretical intelligence-challenging “obstacle course” for ravens.

This lesson could be used following (or in conjunction with) the lesson “Symbiotic Strategies.”

SUBJECT MATTER: Living Environment/Biology

LEARNING OBJECTIVES:

Students will be able to:

• Compare “classical” and “modern” views of bird brain anatomy and function, and compare bird brains to human brains;
• Describe various raven behaviors and abilities that indicate intelligence;
• Explain why many of these behaviors indicate cognitive intelligence rather than simple inherited instinct;
• Assemble a realistic sequence of intelligence-testing challenges for ravens.

STANDARDS AND CURRICULUM ALIGNMENT:

National Science Education Standards

CONTENT STANDARD C: As a result of their activities in grades 9-12, all students should develop understanding of:

THE INTERDEPENDENCE OF ORGANISMS

• Organisms both cooperate and compete in ecosystems. The interrelationships and interdependencies of these organisms may generate ecosystems that are stable for hundreds or thousands of years.
• Living organisms have the capacity to produce populations of infinite size, but environments and resources are finite. This fundamental tension has profound effects on the interactions between organisms.

THE BEHAVIOR OF ORGANISMS

• Organisms have behavioral responses to internal changes and to external stimuli. Responses to external stimuli can result from interactions with the organism’s own species and others, as well as environmental changes; these responses either can be innate or learned. The broad patterns of behavior exhibited by animals have evolved to ensure reproductive success. Animals often live in unpredictable environments, and so their behavior must be flexible enough to deal with uncertainty and change. Plants also respond to stimuli.
• Like other aspects of an organism’s biology, behaviors have evolved through natural selection. Behaviors often have an adaptive logic when viewed in terms of evolutionary principles.
• Behavioral biology has implications for humans, as it provides links to psychology, sociology, and anthropology.

CONTENT STANDARD G: As a result of activities in grades 9-12, all students should develop understanding of

NATURE OF SCIENTIFIC KNOWLEDGE

• Scientific explanations must meet certain criteria. First and foremost, they must be consistent with experimental and observational evidence about nature, and must make accurate predictions, when appropriate, about systems being studied. They should also be logical, respect the rules of evidence, be open to criticism, report methods and procedures, and make knowledge public. Explanations on how the natural world changes based on myths, personal beliefs, religious values, mystical inspiration, superstition, or authority may be personally useful and socially relevant, but they are not scientific.
• Because all scientific ideas depend on experimental and observational confirmation, all scientific knowledge is, in principle, subject to change as new evidence becomes available. The core ideas of science such as the conservation of energy or the laws of motion have been subjected to a wide variety of confirmations and are therefore unlikely to change in the areas in which they have been tested. In areas where data or understanding are incomplete, such as the details of human evolution or questions surrounding global warming, new data may well lead to changes in current ideas or resolve current conflicts. In situations where information is still fragmentary, it is normal for scientific ideas to be incomplete, but this is also where the opportunity for making advances may be greatest.

NEW YORK STATE CORE CURRICULUM ALIGNMENTS

Living Environment Core Curriculum

Standard 1: Students will use mathematical analysis, scientific inquiry, and engineering design, as appropriate, to pose questions, seek answers, and develop solutions.

Key Idea 1: The central purpose of scientific inquiry is to develop explanations of natural phenomena in a continuing and creative process.

Performance Indicator 1.1: Hone ideas through reasoning, library research, and discussion with others, including experts.

1.2a Inquiry involves asking questions and locating, interpreting, and processing information from a variety of sources.

Standard 4: Students will understand and apply scientific concepts, principles, and theories pertaining to the physical setting and living environment and recognize the historical development of ideas in science.

Key Idea 1: Living things are both similar to and different from each other and from nonliving things.

Performance Indicator 1.1 Explain how diversity of populations within ecosystems relates to the stability of ecosystems.

1.1a Populations can be categorized by the function they serve. Food webs identify the relationships among producers, consumers, and decomposers carrying out either autotropic or heterotropic nutrition.

1.1b An ecosystem is shaped by the nonliving environment as well as its interacting species. The world contains a wide diversity of physical conditions, which creates a variety of environments.

1.1c In all environments, organisms compete for vital resources. The linked and changing interactions of populations and the environment compose the total ecosystem.

Key Idea 6: Plants and animals depend on each other and their physical environment.

Performance Indicator 6.1 Explain factors that limit growth of individuals and populations.

6.1g Relationships between organisms may be negative, neutral, or positive. Some organisms may interact with one another in several ways. They may be in a producer/consumer, predator/prey, or parasite/host relationship; or one organism may cause disease in, scavenge, or decompose another.

MEDIA COMPONENTS:

Video

NATURE: Ravens, selected segments:

Clip 1: “Raven Adaptability”

Ravens are the most intelligent birds in the crow family.

Clip 2: “Feeding Time”

Ravens’ smarts can be observed in many situations.

Clip 3: “The Roost”

Why do ravens gather together?

Clip 4: “Testing Intelligence”

Scientific experiments test how ravens think.

Access the streaming and downloadable video segments for this lesson at the Video Segments Page.

Web Sites

Bird Brain
A site from PBS’s NOVA exploring the most current understanding of bird brain physiology, revealing a less instinctive and more cognitive brain structure than has traditionally been thought.

Measuring Intelligence
A site from the Smithsonian National Zoological Park addressing some of the basic difficulties in determining bird intelligence.

The Animal Mind
A NATURE site from PBS describing the intelligent behavior of four different species.

Symbiosis
A site from North Carolina State University featuring descriptions of the different types of symbiotic relationships among animals.

Nutcrackers
A PBS site exploring intelligent behavior in various bird species.

MATERIALS

For each student:

• “Raven Reason” Student Organizer. (PDF) (RTF)
• Computer with Internet access

For the class:

• “Raven Reason” Student Organizer Answer Key (PDF) (RTF)
• Computer with Internet access and projection system for showing video clips
• Blackboard or whiteboard

PREP FOR TEACHERS:

Prior to teaching this lesson, you will need to:

Preview all of the video clips and Web sites used in the lesson.

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

Bookmark the Web sites used in the lesson on each computer in your classroom. Using a social bookmarking tools 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.

Gather the necessary materials listed above in advance of teaching the lesson. Download and print the “Raven Reason” student organizer and make copies for each student in your classroom.

Note that the computer requirements in the “Materials” section reflect an ideal arrangement. You may find it necessary to divide the class into a number of groups equal to the computers available, adjusting the lesson instructions accordingly.

Next: Proceed to Activities

In a Tanzanian jungle, a scientist and a medicine man follow a chimpanzee in search of a cure for a deadly disease. On the plains of Kenya, a woman learns a powerful lesson about family — from a pair of elephants. And in the Florida Keys, an eight-year old boy with a genetic illness utters his first words, for a chance to swim with dolphins.

From the ancient world to the modern, human lives have been influenced by animals in matters that reach far beyond the food chain. Wisdom of the Wild illustrates some of the surprising ways in which animals help teach, heal, and strengthen people, in body, mind, and spirit.

To order a copy of Wisdom of the Wild, visit the NATURE Shop.

Online content for Wisdom of the Wild was originally posted December 1999.

Background:
The traditional view of birds was that they simply acted by a set of inherited instincts, but new scientific research is revealing a larger role for complex cognitive processes in their behavior, including communication, counting, memory, and basic problem solving. These excerpts from the NATURE episode “Ravens” demonstrate several of these commonly accepted indicators of animal intelligence as demonstrated by the most brainy of all birds-the raven.

Suggested Focus Questions:

Clip 1: Raven Adaptability

1. What makes ravens so adaptable?
2. Ravens eat meat but they don’t kill it themselves. What kind of animal does this make them?
3. How might ravens’ relationship with coyotes indicate their intelligence?

Clip 2: Feeding Time

1. What skill does the raven demonstrate at the dumpster?
2. When and why might a raven puff out its feathers?
3. How might ravens’ caching behavior indicate intelligence?

Clip 3: The Roost

1. What’s one theory about why young ravens roost together?
2. How might one raven be able to tell if another knows where food is?
3. Why would a young raven, having found food, call over other ravens to help eat it?

Clip 4: Testing Intelligence

1. Why is it so difficult to measure intelligence in animals?
2. Why is it important that the ravens have never been exposed to the experiment before?

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.)

Clip 1: “Raven Adaptability“

Clip 2: “Feeding Time“

Clip 3: “The Roost“

Clip 4: “Testing Intelligence“

NATURE’s Ravens explores how these all-black creatures acquired their dual and contradictory images — as birds of both life and death.

Long recognized as one of the most intelligent birds, the raven also has a less than savory image throughout history as a scavenger that does not discriminate between humans and animals.

Ingenious and versatile, ravens are members of the crow family, which includes jays and magpies. They are found everywhere in the northern hemisphere and adapt to very different terrain, from deserts to mountains — a feat requiring high intelligence.

They learn to find food even in the harshest conditions, such as the dead of winter in Yellowstone National Park. As scavengers, ravens know how and when to take advantage of other animals to help them cadge a meal they couldn’t otherwise reach. In Yellowstone, bison that don’t survive the harsh winter attract coyotes, whose sharp teeth and strong jaws rip open the tough, frozen hides — making the meat accessible to watchful ravens. They also have been seen following wild wolf packs to a kill; some stories even have ravens flying ahead of the wolves to lead them to prey.

To order a copy of Ravens, please visit the NATURE Shop.

Online content for Ravens was originally published December 2001.

Generally, birds don’t get credit for being smart animals. Just think of the way the expression “bird-brained” is used. But corvids, which include magpies, crows, and ravens in particular, flutter in the face of this negative stereotype. Their behavior is often so clever, cunning, fun-loving, smart, and witty that it has motivated researchers to try to explain why. In fact, some scientists consider these black-feathered scavengers’ position on the intelligence spectrum to be on par with canids such as wolves, coyotes, and dogs, and have conducted experiments to try to quantify the raven’s brainpower.

In NATURE’s Ravens we see zoologist Bernd Heinrich of the University of Vermont work with ravens to see whether they could learn to distinguish between strings bearing food and strings bearing rocks and modify their behavior based on their understanding. The ravens performed well, even when the level of difficulty was increased by crossing the strings.

Heinrich has also used anecdotal evidence to point to raven cognitive intelligence. For example, the researcher flushed a bird off a frozen chunk of suet and observed upon inspection that the raven used its beak to carve a precise groove around the fat, allowing it to carry off a large chunk at once instead of several small morsels to eat one at a time. Heinrich commented that “the raven not only had thought ahead, but also had acted on that thought and shown intelligence.”

A central question that presents itself is whether the raven’s sharp behavior indicates complex cognitive processes associated with human learning. Johannes Fritz and Kurt Kotrschal of the University of Vienna, Austria, attempted to provide an answer with an experiment similar to Heinrich’s. Ravens were asked to perform a task — opening a box to get a reward — and then teach the behavior to their fellow birds. According to Henry Gee of Nature Magazine Online, while the birds’ performance indicates a high learning level, the results are inconclusive because it’s impossible to tell how the ravens learn: is it by a complex form of “imitative learning” or by a lesser process known as “stimulus enhancement”?

Gee suggests that while ravens might learn by stimulus enhancement, which means that a learner raven might simply come to link the act of opening a box with getting a reward, it seems likely that the corvids engage in imitative learning, which Gee states is “considered to be the most demanding category of social learning, because it requires the learner to translate what it sees (sensory input) into its own actions (motor output).”

How then can one account for corvids’ seemingly complex decision-making skills? After all, birds don’t have a cerebral cortex, so at one time their actions were considered robotic in nature. But in the 1960s, neurologist Stanley Cobb found that birds have a part in the forebrain, called the hyperstraiatum, that allows them to perform synonymous functions, and that ravens have among the largest brains of any birds as well as a relatively high number of brain cells. Natural history author Candace Savage writes: “Crows, ravens, magpies, and jays are not just feathered machines, rigidly programmed by their genetics. Instead, they are beings that, within the constraints of their molecular inheritance, make complex decisions and show every sign of enjoying a rich awareness.”

Beyond explaining how and why ravens act as they do, it’s how this innate intelligence manifests itself in behavior that makes these birds fascinating to observe. As seen on NATURE, ravens achieve mastery and possess manipulative powers over other creatures in their domain, often letting others do work for them. For example, ravens will call wolves and coyotes to prospective meals so they can expose the carcass and make the meat accessible to the birds. In addition, ravens will show their true scavenger colors by waiting for other birds with specialized foraging skills to make a catch and then cunningly seize the defeated prey for themselves.

Not all raven behavior is so devilish; some is merely mischievous and even good-natured. On NATURE, we are treated to a raven frolicking in the snow as well as the domesticated pet raven named Loki soothingly and majestically flying alongside her owner’s vehicle. Seeing how affectionate and keen these birds are, it’s easy to understand why one might want to keep a pet raven. As Loki’s owner, Rose Buck, says, “Loki’s bright, clever, very intelligent, and mischievous. Sometimes, he can be an absolute pain, but I wouldn’t be without him. He’s just great.”

Though it might be tempting to run right out to your local pet store to buy a raven, they aren’t available and, more importantly, are federally protected in the United States; it’s illegal to buy or even hold a raven (unless one has a difficult-to-obtain permit). However, many people successfully raise orphaned, nestling crows under 3-4 weeks old to the point where they are able to eat independently, and then release the birds when they are approximately eight weeks old. Information on diet and care of orphaned ravens, as well as a wealth of other material, can be found on the American Society of Crows and Ravens Web site.

Considered by many wildlife biologists to be one of the most intelligent land animals of North America, bears possess the largest and most convoluted brains relative to their size of any land mammal. In the animal kingdom, their intelligence compares with that of higher primates. As highly evolved social animals, bears form hierarchies and have structured relationships with each other, sometimes even sharing resources. In fact, the polar bear, typically thought of as solitary, actually lives within a community of other polar bears and never loses track of other members.

We’ve witnessed them performing complex tasks — a sign of an ability to learn and process information. We’ve seen circus bears balance on balls, ride vehicles or roller skate, and play sports and musical instruments. Zookeepers and animal trainers consider bears to be smarter than dogs.

The bear’s cunning is legendary when it comes to guarding itself against danger from hunters and poachers. The animal’s uncanny ability to evade human predators during hunting season could almost be considered forethought. Some researchers believe that grizzlies possess self-awareness, as there have been accounts of grizzly bears covering their tracks or concealing themselves from hunters with rocks and trees.

Beyond this ursine wiliness, we find further proofs of their intelligence in their habits. Like humans, bears are omnivores. It’s well known that omnivores are often substantially smarter than more specialized feeders. Following a varied diet means that bears have to remember a great deal of information about food sources — where to find which foods and when. A grizzly’s memory is so sharp that he can remember where they encountered a certain food ten or more years earlier. And bears remember familiar animals for years, recognizing them and identifying their social status from a distance as far as 2,000 feet away.

It helps that bears are creatures of detail. They take constant inventory of their surroundings, allowing them to compile a detailed map of their territories, complete with information on where to find their preferred foods and when they can obtain them. The polar bear lives in a world of an ever-changing landscape. Hunting and surviving within an ice relief below water and on the surface demands a sharp memory.

To learn survival skills from their mother, cubs spend several years with her. She educates them about what plants are good to eat and where to find them. By the time a juvenile bear leaves its mother, it knows what plant foods are available at each time of the season, and what habitats are likely to have those foods over a very large area. That knowledge serves them well as they move into new areas, learning and remembering where new food sources are found in a new environment. This knowledge is also critical to finding food when food sources change drastically from year to year depending upon weather and climate.

In our own encounters with wild bears, we know that a bear’s resourcefulness seems to know no limits. Bears have long been engaged in a battle to figure out ways in which to benefit from living in close proximity with us. They are constantly devising new ways to get at garbage, empty birdfeeders, devour fruits from orchards and farms, clear out beehives, and open metal and glass cars to get to food that their keen sense of smell draws them to. The occurrence of polar bears scavenging in town dumps in Manitoba is on the rise. And both grizzly bears and polar bears have become more popular visitors of the dump in the North Slope town of Prudhoe Bay, Alaska. Grizzly bears in national parks have become so adept at getting into garbage bins and camper trash, that new models of supposedly “bear proof” containers are rolled out each season. New models are “market tested” with grizzlies who had to be removed from the wild because they were too comfortable around humans.

As highly intelligent and adaptable as bears are, they continue to suffer an unfortunate fate at our hands. Many bears are needlessly captured and shot because of human fear and carelessness. “Nuisance” bears, or bears that raid garbage or property, are only a nuisance when humans fail to take precautions that can keep the bears away. As humans move into territories that traditionally belong to the bears, encounters between the two will become more common. As intelligent as bears are, humans are the more advanced and intelligent species. It is our responsibility, then, to ensure that these creatures live safely within both of our worlds.

Birds may have a reputation for being less than geniuses, but researchers are discovering that some are remarkably smart.

Some birds have the capacity to recognize, count, or name different objects.

Ravens, for instance, have the ability to solve difficult puzzles, such as untangling a knotted string to free up a tasty treat or figuring out how to steal fish by hauling in an angler’s untended line. And, as shown in the first part of NATURE’s Inside the Animal Mind, crows on the remote Pacific island of New Caledonia have learned a skill that people once thought only primates could master: the use of tools. The birds use long, specially chosen twigs to spear the plump grubs that hide deep beneath the bark of rotting logs.

Some birds have the capacity to recognize, count, or name different objects.

Raven antics and New Caledonia’s clever crows have helped make people much more willing to admit that many animals, including birds, are quite intelligent. Dolphins can follow complex instructions, for instance, while orangutans learn complex tasks, such as washing clothes by hand, after just a few tries. And even pigeons and parrots have shown an extraordinary capacity to recognize, count, or name different objects.

But no bird has done more to give a whole new meaning to the phrase “birdbrain” than Alex the African Grey parrot. More than 20 years ago, researcher Dr. Irene Pepperberg of the University of Arizona began systematically studying Alex and several other African Greys, parrots that are remarkable mimics, to understand avian intelligence. “Before I began my studies, I knew that parrots could reproduce the sounds of human speech, but that the general belief was that such vocalizations could not be meaningful,” Pepperberg has written.

Today, her work with Alex has challenged that notion. For instance, Alex can name more than 40 objects and understands the concepts of “same” and “different,” “absence,” “quantity,” and “size.” Alex, Pepperberg says “has mastered tasks once thought to be beyond the capacity of all but humans or certain non-human primates.