Observation of a Living Frog
Looking for live frogs to go with this lab? You can order them from a variety of sources or raise them yourself if you can find and collect tadpoles in the spring. Toads are also an acceptable alternative.
Procedure: Working in groups of 4, teams will observe the behaviors of a live frog. Find the answers to all questions, and report on a separate piece of paper. For each number, include the question you are answering on your paper (the heading). The bulleted lists are there to help you answer the question entirely. Make sure you are thorough.
Materials: One grass frog, small terrarium, crickets or mealworms, ice packs, flashlights.
Frog Handling: When handling the frog be careful not to allow the frog to slip from your grasp and injure itself by jumping onto the floor or the table. A wet paper towel can be used to gently hold the frog.
1. How Does a Frog Hang Out?
- Observe the frog in the terrarium and determine its most comfortable position. Sketch the frog as it rests (be sure to focus on the position of its legs)
- What features of an adult frog show evidence that this animal has both an aquatic and terrestrial lifestyle?
2. How Are the Frog's Eyes Specialized?
- Observe the frog's eyes and describe them. Pay attention to the position of they eyes compared to the rest of the body. Do they have an eyelid?
- Gently blow on the frog's eyes and describe what happens.
- The nictitating membrane is a clear membrane that covers the eyelid. Is the nictitating membrane always visible? Where does it attach (to the bottom or top of eye)?
- Use a penlight to shine into the frog's eye. Does the pupil dilate? Compare the frog's reaction to light shining in the eye to a human eye's reaction. (Use someone in your group as a guinea pig but do not shine the light for long periods of time into the human or the frog's eye)
- Explain how the frog's eye is adapted to the frog's lifestyle.
3. Can the Frog Orientate itself?
- Gently tilt the terrarium back and forth into various orientations and describe how the frog responds.
- Try spinning the terrarium in slow circle, does the frog seem to want to face one direction?
- Would you hypothesize that amphibians possess an organ of balance in their inner ear as humans do?
4. Do Frogs Talk and if they Could, What Would They Talk About?
- Often, if you hold a frog and rub its sides it will croak. See if you can get your frog to talk by doing this.
- What are some reasons that frogs croak in the wild?
5. How Does a Frog Breathe?
- Observe the frog as it rests, notice that its throat moves up and down. This is how a frog pulls oxygen into its lungs.
- Compare a frog's breathing rate at room temperature to its breathing rate in colder temperatures. Use an ice pack to lower the frog's temperature. Create a data table and write your conclusions.
6. How Does a Frog Swim?
- Take your frog to one
of the swimming tanks and gently release it into the water.
- Describe how the frog swims. Which legs propel the frog? Does the frog swim in a side to side motion like a fish?
- Do not leave your frog in the swimming tank for very long. Remove your frog and return it to the terrarium.
7. How Does a Frog Eat?
- Place a cricket or mealworm into the terrarium with your frog.
- Observe the frog and describe how it responds. Does the frog chew or swallow its prey whole?
- If your frog does not eat within a few minutes, remove the food. If your frog didn't eat, propose a reason why your frog was being contrary.
8. Can You Hypnotize Your Frog?
- A frog can be placed in a "hypnotic" state. Lay the frog on its back and hold it firmly in your hands until it stops moving. Slowly open your hand, the frog will remain motionless and on its back.
- Try to place your frog in a hypnotic state. Suggest reasons that this behavior exists. What advantage might it be to the frog?
9. How Far Can a Frog Jump?
- Some communities hold frog jumping contests. Frogs are excellent jumpers. Place your frog on the floor and use a meter stick to measure how far the frog can jump in a single leap. Be careful not to lose your frog!
- Compare your frog's distance to other frogs and construct a table with data from at least 5 other frogs.
- Are some frogs better jumpers than others?
10. What's Up With a Frog's Skin?
- Describe the texture of the frog's skin.
- Describe the coloration of the frog. Are all frogs the exact same, do they follow a pattern of coloration. Is countershading exhibited in frogs?
- Explain how the coloration of the frog helps it survive.
- How is a frog's skin different from a human's skin?