This lesson was developed by Dr. Cynthia Annett, who has her doctorate from the University of California at Berkeley in Zoology with a
You can find additional resources for this lesson by clicking on these links:
Amphibian and Reptile species on Friends of the Kaw's Critter Corner website
Kansas State Standards can be downloaded in Word format from our school standards page
Materials used to reproduce frog songs can include balloons, musical instruments, door hinges, or any other "sound effects" equipment that the students can imagine. Use a video camera or digital tape recorder to make an audio file of the students imitating frog calls and compare them to the sounds made by the frogs recorded in the YouTube videos and Kansas Herpetological Atlas.
Method: This should be a creative exercise that engages the student's imagination and shows them how to listen for differences in pitch, duration, repetition and other characteristics of mating calls.
Students are provided with a series of prompts to help them focus on characteristics that are important in differentiating between the calls of different species (see Lecture/Discussion section below). After listening carefully to each frog call in the three YouTube videos the students will create sounds using words, their voices, musical instruments and other objects to try to imitate the calls.
Once the students have perfected their frog songs, create a chorus of frogs. Divide the class into groups and have students make their calls simultaneously to create the sounds of a pond in the spring. Choose a student and give them the name of one of the three species, then see if the student can find a "froggie prince" of the proper species from the mixed groups (you can turn off the lights or blindfold the student to simulate nighttime, which is when most of the females will be visiting the pond). Alternatively, you can have students conduct a population census of the pond by counting the number of each species that they hear for a five minute period. If there is a safe place to take a field trip during the breeding season, you can then have the students attempt to census a real frog population in the field.
Instructor will: Lead students in a discussion and investigation of a behavioral cue used by female frogs to choose a mate. This will be an exploratory lesson that uses song, musical instruments, sound effects, and written descriptions to capture the differences between the calls used by different species so that students learn to carefully observe animal behavior and record their observations.
Students will: Students will demonstrate an
understanding that frogs use calls to identify themselves to potential mates and that these calls differ in often subtle ways.
Evaluation: Students may produce written or audio recordings that can be used to evaluate how well they have learned to discriminate between the calls of different species. This is both a scientific and a creative lesson, so attention should be paid to how well the students invent different ways of listening to and reproducing the calls.
Students will demonstrate: An understanding of how behavioral differences between closely related species are important in taxonomy for classifying them. This will be important in the discussion of newly discovered species in Name That Frog!
How would you describe each of the songs?
Herpetologists often provide a written account in field guides and species accounts of the call used by each species. For example, the Kansas Herpetological Atlas describes the call of the Plains Leopard Frog as "a series of abrupt guttural notes, two or three a second, which resemble a finger rubbing a balloon." Have students try to come up with descriptions that can be written down and which will evoke some pertinent characteristic of the calls. Students can exchange their written descriptions and use them to try to reproduce the sound using their voices, musical instruments or other objects.
Are there words or sounds you can make yourself that sound like the three different frog calls?
Scientists sometimes find words that somewhat resemble a call and use this as a devise to help them remember it when they are doing surveys in the field. For example, different species of Leopard Frogs might be described as saying "chuck" or laughing. Encourage the students to use their imaginations to find words that might sound like the frog calls.
It may be hard to imitate the frogs yourself, so see if you have anything around the house or your classroom that you can use to help you imitate their songs; things like balloons, or creaky doors or other sound effects.
Frog calls are sometimes said to sound like someone rubbing their finger on a balloon or closing a creaking door. Encourage students to be creative in finding objects to help them imitate the frogs. You may want to compare this to the various types of calls used by people to imitate moose or ducks or turkeys (they have contests all around the U.S. to see who can come closest to imitating the animals). You may want to have the students consider the differences in how they produce sounds when they talk and how the frogs produce sounds in the YouTube videos (you can watch them fill their cheek pouches and use other parts of their anatomy that differ from human anatomy).
Try to pay attention to how many times they repeat different sounds, and how long the sounds last. Different species of frogs may use the same sound but at different speeds or in different combinations.
This is an important point; many closely related species vary in minor details of their calls. But even minor details can be used by females to decide which male to mate with, and thereby serve as an isolating mechanism between species. For example, two species may use exactly the same pitch, but differ in the number of calls they give per minute. See if you can get the students to think about it in terms like musical pitch, rhythm and phrases.
If you have a video or a digital tape recorder you may want to make a recording of your Frog Song so that you can add it to your Virtual Froggie.
Students can add video and audio files to the PowerPoints that they will make in the Virtual Froggie lesson. If they can record themselves making frog calls have them save the recordings for later lessons in this series.References
The Kansas Herp Atlas has audio recordings of each species in their species accounts, as well as written descriptions of what herpetologists use to describe the calls in written form.
HerpNet provides videos of a number of different frog species