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As the Frog Hops: What Routes Do Frogs Travel in Mountain Environments?

Frogs are a species of amphibian. In recent years, there has been a decline in the numbers of amphibians worldwide. This decline is thought to be caused by many things. The scientists in this study wanted to discover the types of habitats needed by Columbia spotted frogs at different times of the year. The scientists also wanted to find out how far Columbia spotted frogs will travel or migrate to reach different habitats and which routes they take when they are migrating.

As the Frog Hops: What Routes Do Frogs Travel in Mountain Environments?

Meet the Scientists

David Pilliod

Ecologist

Peter Ritson

Ecologist

Charles Peterson

Biologist

Thinking About Science

Sometimes, environmental scientists must do their research in natural areas away from the disturbance of humans. In the United States, there are few natural areas left where people have not disturbed the land and water. When Congress created the National Wilderness Preservation System, they intended that among its many purposes, wilderness would be used for scientific research.

In this research, the scientists wanted to study the migration of frogs at high elevations. They needed to find a large natural area that had several populations of frogs and was not disturbed by human activity. They identified an area called Skyhigh Basin, which is located within Frank Church-River of No Return Wilderness in Idaho (figures 1 and 2). As part of a wilderness, Skyhigh Basin is protected from machines and all human development. Because it is almost 12 miles from a road, few people go there. It was the perfect place to study the migration of frogs.

Map of Idaho with Boise and the Frank Church River of No Return Wilderness area highlighted with a star — **Figure 1**. Location of Frank Church – River of No Return Wilderness in Idaho

Mountains in the background with two basin in the foreground with many trees — **Figure 2**. Skyhigh Basin.

Thinking About the Environment

Did you know that frogs are complex animals? For many frogs, each season brings the need for a different habitat. You probably know that as tadpoles, young frogs must have water to live. Actually, frogs need watery habitat throughout their lives. They need areas to reproduce, find food, and hibernate. Because one area might not provide for all of these needs, frogs can migrate from area to area, depending on the time of year.

In this research, the scientists wanted to know how far and to which habitats a certain species of frog migrated. This particular species is called the Columbia spotted frog. Although it is found throughout the mountains of the Northwestern United States, its population has become threatened in some areas. One of the reasons is the introduction of non-native trout, which eat the tadpoles. Other reasons for the decline in frog populations include taking water from natural streams and lakes for human purposes and the loss of habitat to human development, such as buildings and roads.

Introduction

Frogs are a species of amphibian. In recent years, there has been a decline in the numbers of amphibians worldwide. This decline is thought to be caused by many things. A few of those reasons are mentioned in the “Thinking About Environment” section.

Natural resource managers need to have more information to protect frog populations. Not much is now known about the habitats needed by frogs. The scientists in this study wanted to discover the types of habitats needed by Columbia spotted frogs at different times of the year (figure 3). In the early summer, these frogs breed and lay their eggs. The adults then spend the summer finding food, an action called foraging. During the winter, they hibernate under water. (The frogs do not breathe while under water, but absorb oxygen from the water through their skin.) The scientists also wanted to find out how far Columbia spotted frogs will travel or migrate to reach different habitats, and which routes they take when they are migrating.

Reflection Section

Methods

The first thing the scientists did was identify and map all of the bodies of water in Skyhigh Basin (figure 4).

two pictures of the study sight in Skyhigh basin. One shows the mountain range as well as the streams and lakes. — **Figure 4**. The study site in Skyhigh Basin . In this figure, a photograph is shown on the right. The location of the lakes is shown in blue . The streams are shown as blue lines. Lakes, 4, and 9 are identified . On the left, the location of all of the lakes is shown as a map. Using the map as a guide, locate the lakes on the photograph.

Beginning in the early spring, the scientists walked around the edge of each lake and pond and looked for Columbia spotted frogs (figure 5). They also looked for frogs while walking along the banks of streams. In nearby water-filled meadows, the scientists walked back and forth through the meadows looking for frogs.

Scientist using nets in a lake looking for frogs — **Figure 5**. Scientists looking for frogs in the lakes. (Photo by Peter Landres)

When frogs were found, they were caught, measured, weighed, and released. The sex of each frog was also recorded along with its measurements and weight. The scientists marked the toes of each frog. The marking indicated the habitat in which each frog was first captured.

Some of the female frogs were fitted with a transmitter that was placed around the waist (figure 6).

**Figure 6**. Scientist placing a transmitter on a female frog.

The transmitter allowed the scientists to track the movements of the female frogs. The scientists checked the female frogs every 1-3 days to make sure that the transmitters were not cutting the frogs’ skin. If the frog had any shallow cuts, the scientists put Neosporin® ointment on the skin before releasing the frog. If the cuts were deep, the scientists removed the transmitters so that the frogs would not be harmed. The scientists tracked the movements of the frogs throughout the summer and into the early fall.

When frogs were found during their breeding season, the areas in which they were found were identified as breeding habitat. When frogs were found during the middle and late summer, the areas in which they were found were identified as summer foraging habitat. In late August and early September, the areas in which frogs were found were identified as winter habitats.

Reflection Section

Findings

The scientists identified a number of different habitats according to the use that was made of the habitat (figure 7).

Figure 7. Types of habitats used by Columbia spotted frogs.
Time of year	Habitat use	Description of habitat
Early July	Breeding	Small, silt-bottomed lakes with no fish; or larger, rock-bottomed lakes with little vegetation.
Early July to late August	Summer foraging	All types of wetland habitats.
Mid-August and later	Winter habitat	Large, deep rocky lakes with a constant flow of water into and out of the lake. Some of these lakes had nonnative trout living in them.

Shortly after laying eggs in early July, some of the adult frogs began to leave the breeding habitat for summer foraging. A greater number of female frogs migrated from their breeding habitat than males or young frogs that had not yet begun to breed. After 4 weeks, adult male frogs were found up to 424 meters away from the breeding habitat. Adult females were found up to 1,033 meters away.

Number Crunches

The scientists wondered if the difference in distances migrated was due to the sex of the frog or its size. The scientists found that larger frogs migrated farther than smaller ones.

At the end of the summer, the frogs migrated to winter habitat. The scientists found that the youngest frogs traveled up to 350 meters from breeding habitat to winter habitat areas. These young frogs had recently undergone metamorphosis, and so had spent the summer growing from tadpoles into frogs. The scientists found that the adult frogs traveled up to 708 meters in a day. Some of the female frogs traveled between 50 and 160 meters per hour. Most of the females migrated during the nighttime when the temperatures were cooler.

Number Crunches

The scientists found that when the female frogs migrated from place to place, they generally traveled in a straight line. They did not follow the streams that connected the habitats (Look again at figure 4, under “Methods”). By traveling a straight distance over dry ground, the frogs shortened the distance they had to travel by up to 1 kilometer (1 kilometer = .621 miles) (figure 8).

A illustration of a migration pattern on a stream from one lake to another — **Figure 8**. An example of the migration pattern of one of the female frogs. You can see that these frogs generally traveled in a straight-line direction.

Reflection Section

Discussion

This research indicates that frogs living in the high mountains of the American West need a diversity of water bodies as well as the drier habitats between them. Scientists had previously thought that frogs migrated only along streams or other water bodies. The scientists in this study found that frogs will also travel across dry areas to reach a desired water body. Frogs generally travel when it is raining or at night, which may help them travel across areas with no water. A frog’s ability to travel quickly may also help them to travel across dry areas.

If natural resource managers want to protect the Columbia spotted frog population or similar frog species, they should focus on at least two things. First, they should protect many types of water bodies in mountainous areas of the American West (See figure 7 under “Findings,” above). In addition, the scientists suggest that managers should protect the dry land areas within 1 kilometer of these water bodies.

Reflection Section

From Pilliod, D.S., Peterson, C.R., and Ritson, P.I. (2002). Seasonal migration of Columbia spotted frogs (Rana luteiventris) among complementary resources in a high mountain basin. Canadian Journal of Zoology, 80: 1849-1862.

Wondering About Wilderness

What are public lands? Public lands are lands owned by the citizens and managed by a government agency for citizens’ benefit. Our Nation’s largest areas of public lands are managed by the Federal Government. There are many categories of Federal public lands. One of these categories is wilderness. Wilderness is different than any other Federal land. Land that is wilderness has been granted legal protection from human development. Because of this protection, wilderness provides many benefits.

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What Is a Natural Inquirer Journal?

Three Natural Inquirer journal covers with NI bee

A Natural Inquirer journal is a collection of 4-8 articles on a related science topic. Journals are written for a middle school audience, but they can also be adapted for both high school students and advanced upper elementary students. Some journals are particularly suited to high school students; you can find our grade level recommendations in the tags on the product page or by filtering journals by grade level.

Journals include:

Four to eight articles based on published, peer-reviewed research papers; the articles keep the research paper format (see more below) but are written in language students can understand.
A FACTivity for each article, which is an activity to complete after reading the article. The FACTivity helps reinforce major science concepts from the article. These activities are designed to be easy to implement, with few material requirements and options for adapting them for your audience or available resources. Some articles in a journal may have two FACTivities.
A short “Welcome to the journal” article about key background information and science concepts that unify the articles included in the journal
A glossary of new terms for each article and the introductory materials.
A list of related Natural Inquirer publications for each article as well as outside references.
Standards correlations, including Next Generation Science Standards, addressed in the articles and the FACTivities.

Journals may also include additional essays (called spotlights), other activities (like crossword puzzles or vocabulary challenges), and more.

A screenshot of the article resource tile for "A Flame Changer" showing the three different format option buttons.

Reading Modes

Journals are available in three different formats:

Hard copies can be ordered from the website and shipped, all free of charge.
PDF versions of the printed journal can be downloaded free on the website. The PDF version directly replicates the content and layout of the printed version. You can also download individual articles as pdfs.
The “Read Distraction Free” option allows the individual articles to open in their own window, without the rest of the website being visible. These articles can be found under the “Articles” tab. This version allows readers to scroll to particular sections of the article using the sidebar menu on the left side of the screen. This version also has interactive Reflection Sections and Number Crunches. Students can enter their answers, submit them, and then receive the correct answers to double-check their work. Submitted answers are not saved on the website and will disappear once the window is closed.

What's in a Natural Inquirer Article?

Here, we'll go into more detail about the parts of a Natural Inquirer article and give you some ideas about how they can be used.

Meet the Scientists
This section introduces the scientists (and others) who worked on the study. In their own words, they each share a memorable science experience, a favorite research project, or something they learned during the course of their education or research.

Use this section to:
- Introduce kids to the variety of people who work in science
- Introduce kids to the variety of scientific fields and give brief descriptions of science-related jobs
- Explore ways that people interact with science every day
Next Generation Science Standards (NGSS) applications:
- Science and Engineering Practices
- Crosscutting Concepts: Influence of Science, Engineering, and Technology on Society and the Natural World
Note that specific standards for this particular journal are linked on this educator guide tab.

Other resources:

Many of the scientists and engineers featured in this section are also featured on our collector cards. Learn more about their work, how they got interested in their fields, and interesting projects they worked on. Cards can be printed as posters, too.
Thinking About Science
This section briefly describes a concept about science or scientific research. This overview can touch on topics like
- study type (longitudinal study, quantitative vs. qualitative data),
- behaviors of scientists (conducting literature reviews, collaborating with other specialists, replicating earlier studies),
- the practice of science (the scientific method, engineering design, data collection, randomization, controls and variables),
- or other aspects of science (bias, correlation vs. causation).
Use this section to:
- Reinforce steps in the scientific method and the process of science
- Encourage students to think about the practice of science and what it can and cannot tell us
- Consider the many types of scientific study and what information each type can provide
Next Generation Science Standards applications:
- Science and Engineering Practices
- Life Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.

Other resources:

You can use key words to search for other or related scientific topics on our website (e.g. “longitudinal study,” “bias,” or “sampling”).
Thinking About the Environment
This section provides a brief overview of a topic or concept in environmental/life science. The topic or concept is directly related to the research study that follows. Examples of topics include the carbon cycle, the water cycle, habitat fragmentation, phenology, biodiversity, and ecosystem services.

Use this section to:
- Provide important background information to help students understand the research study
- Serve as a quick reference during reading or class instruction
- Connect the research article with other activities or media on the same topic
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.

Other resources:

You can use key words to search for more resources on life or earth science topics on our website (e.g. “habitat,” “carbon,” or “genetics”).
Introduction
This section begins the scientific article format. Much like the published, peer-reviewed study this article is based on, the introduction provides background information for the study – what is currently known and what remains unknown. The introduction culminates in the question(s) the study hopes to answer.

The introduction is also the first section with a Reflection Section. This section includes two or three questions to help kids reflect on what they’ve just learned in the Introduction. If they are using the online distraction-free reading mode, they can answer these questions directly on the website.

Use this section to:
- Review important background information that kids need to understand the study
- Connect the study to the concepts addressed in the Thinking About Science and Thinking About the Environment sections
- Understand research questions and hypotheses, including generating their own hypotheses given what they already know
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.

Other resources:

Use one of the guided reading lesson plans to help kids follow the format of a scientific paper.
Methods
This section is the nuts and bolts of the study design – the who, what, when, where, why, and how of the research. Contained within the Methods section are usually maps of the study location or the set-up of study plots, as well as details about what data was collected and how.

The Methods section also ends with a Reflection Section – two or three questions to help students think through what they just read. These questions are interactive on the distraction-free reading mode.

Use this section to:
- Show students how experiments and studies are designed and carried out
- Explore sampling methods and randomization
- Introduce various data collection tools (e.g. camera traps, surveys, insect collection tools, weather stations, etc.)
- Explain bias and how studies are designed to remove bias
- Help students gain experience with map reading
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.

Other resources:

Many Methods and Findings sections contain Number Crunches, which are simple math exercises designed to help students interact with the data from the study.
Findings
This section summarizes the data collected during the study. The Findings section usually includes data tables or graphs and highlights the significant data points from the study. This section often mentions statistical analysis or the use of computer programs to model or analyze the data, though these methods are only discussed generally.

The Findings section also ends with a Reflection Section – two or three questions to help students think through what they just read. These questions are interactive on the distraction-free reading mode.

Use this section to:
- Have students practice reading and interpreting graphs and tables
- Compare results between variables and controls
- Explain the concept of statistical significance
- Discuss how no data or negative results still provide valuable information
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.

Other resources:

Search the website for “map” or “graph” to find activities where students can practice making and reading maps and graphs.
Discussion
This section concludes each article. In it, we summarize the main findings of the scientists’ study. Additionally, we present the scientists’ ideas about the limitations of their study, the big-picture impacts of their research, and the scientists’ plans for future study or action.

The Discussion section ends with a Reflection Section – two or three questions to help students think through what they just read, especially general take-aways from the study. These questions are interactive on the distraction-free reading mode.

Use this section to:
- Discuss what conclusions can and cannot be drawn from the available data
- Explain the difference between correlation and causation
- Explore study limitations and opportunities for further study
- Brainstorm ways the study findings could be applied to real-world situations
Next Generation Science Standards applications:
- Life Science and some Earth Science Disciplinary Core Ideas (depending on topic)
- Most Crosscutting Concepts (depending on topic)
Note that specific standards for this particular journal are linked on this educator guide tab.

Other resources:

Use the “Designing Your Own Study” resource page for videos of scientists discussing their own research studies. The page also includes educator resources to help students plan their own scientific studies.

Additional Resources on the Website

A screenshot of the product tabs for an NI monograph On the website, we pair each journal with a variety of other resources, as well. Use the tabs on the product page to browse through the following:

Related activities, including the FACTivity for each article
An “About” essay that gives some larger context for the research the scientists conducted or more information about the science topic from the journal
A glossary of all boldfaced terms from the journal
A “Scientists and Collaborators” page that lists the people involved in the studies in the journal; click on a researcher to reach their bio page and see what other articles they might be featured in
A “Related Content” page that lists both Natural Inquirer resources about similar topics and also outside reference materials

Article Selection and Review

Natural Inquirer partners with the USDA Forest Service, so we source research studies by Forest Service scientists that have been peer-reviewed and published in reputable journals. Some of our articles have also been created in collaboration with scientists from other Federal agencies, such as U.S. Geological Survey and the United Nations Food and Agriculture Organization, universities, and other non-profits.

All journal articles are reviewed by scientists who conducted the original research study to verify scientific accuracy. Journals are also reviewed by student editorial review boards of middle or high school students before publication. Additionally, all journals are reviewed by the Forest Service and the U.S. Department of Agriculture before publication.

A screenshot of the citation for "Lights, Camera, Tracks" Every journal article includes a citation of its source study. Many educators pair the original research paper with our article to help more advanced students learn how to read formal research papers. The journal article then serves as adapted primary literature, bridging the two articles.

Lessons

This five-day lesson plan can be used in whole or in part to accompany the Wilderness Benefits edition of Natural Inquirer. Students will brainstorm and then research features of wilderness...
Lesson Plan – Wilderness Benefits
This five-day lesson plan can be used in whole or in part to accompany the Wilderness Benefits edition of Natural Inquirer. Students will brainstorm and then research features of wilderness...
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- Download Lesson Plan (PDF)
- Explore Lesson Plan
- Download Lesson Plan (PDF)
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Students learn how to note important parts of a text by highlighting sentences that help them answer the Reflection Section questions. This lesson plan can be used with any Natural...
Lesson Plan – Highlighter
Students learn how to note important parts of a text by highlighting sentences that help them answer the Reflection Section questions. This lesson plan can be used with any Natural...
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- Download Lesson Plan (PDF)
- Explore Lesson Plan
- Download Lesson Plan (PDF)
Students work together to answer questions about an article generated by rolling the question cube. This lesson plan can be used with any Natural Inquirer article.
Lesson Plan – Question Cube
Students work together to answer questions about an article generated by rolling the question cube. This lesson plan can be used with any Natural Inquirer article.
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- Download Lesson Plan (PDF)
- Explore Lesson Plan
- Download Lesson Plan (PDF)

Education Files

Project Learning Tree

If you are a Project Learning Tree trained educator, you can use “Life on the Edge” and “Web of Life” as additional resources.

Glossary

View All Glossary

amphibian
(am fi bē ǝn): Any of a class (Amphibia) of cold-blooded vertebrates (such as frogs, toads, or salamanders) that have many characteristics that place them between fish and reptiles and having gilled aquatic larvae and air-breathing adults.
boreal
(bȯr ē ǝl): Of, relating to, or located or growing in northern or mountainous regions, characterized especially by dominance of coniferous forests.
colleague
(kä lēg): A fellow worker or professional.
Congress
(käŋ grǝs): The supreme legislative body of a nation and especially of a republic; in this case, the group of elected officials in the United States that makes the laws, made up of the Senate and the House of Representatives.
elevation
(e lǝ vā shǝn): The height above sea level.
habitat
(ha bә tat): The place or environment where a plant or animal naturally or normally lives and grows.
hibernate
(hī bǝr nāt): To pass the winter in a sleeping or resting state.
metamorphosis
(me tǝ mȯr fǝ sǝs): The process of basic and usually rather sudden change in the form and habits of some animals during transformation from an immature stage (as a tadpole or a caterpillar) to an adult stage (as a frog or a butterfly).
migration
(mi gra shun): The act of moving from one place to another.
native
(nā tiv): Living or growing naturally in a particular region.
natural resource manager
(na ch(ǝ) rǝl rē sȯrs ma ni jǝr): A person who cares for and oversees the use of natural resources.
population
(pä pyǝ lā shǝn): The total of individuals occupying an area.
silt
(silt): Very small particles left as sediment in water.
species
(spē sēz or spē shēz): A category of living things that ranks below a genus, is made up of related individuals able to produce fertile offspring, and is identified by a two-part scientific name.
wetlands
(wet landz): Land or areas (such as marshes or swamps) that are covered, often intermittently, with shallow water or have soil saturated with moisture.
wildlife
(wī(e)l(d) līf): Living things and especially mammals, birds, and fishes that are neither human nor domesticated.

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FACTivity – As the Frog Hops

Who or What Am I? – As the Frog Hops

Standards addressed in this Article:

What Is a Natural Inquirer Journal?

Reading Modes

What's in a Natural Inquirer Article?

Meet the Scientists

Thinking About Science

Thinking About the Environment

Introduction

Methods

Findings

Discussion

Additional Resources on the Website

Article Selection and Review

Lessons

Lesson Plan – Wilderness Benefits

Lesson Plan – Highlighter

Lesson Plan – Question Cube

Education Files

Project Learning Tree

Glossary

amphibian

boreal

colleague

Congress

elevation

habitat

hibernate

metamorphosis

migration

native

natural resource manager

population

silt

species

wetlands

wildlife

Charles Peterson

David Pilliod

Peter Ritson