In December of 2012 we ordered bullfrog tadpole as a way to expose my young children to science.
Here are all of the bullfrog photos that we currently have available, grouped by stage of metamorphosis.
American Bullfrog Tadpoles Before Metamorphosis
Our bullfrog tadpoles did not begin metamorphosis until they were 9 - 10 months old. Click on image to enlarge and expand view of film strip.
1, 2 & 3. Individual tadpoles; 4 & 5. Tadpoles side by side. Same age. Note size difference.
All photos individual American bullfrog tadpoles.
All photos tadpole head and mouth.
American Bullfrog Tadpoles with Rear Legs
The first noticeable change in tadpole metamorphosis is the appearance of legs. The tadpole legs start out small and straight, then grow and develop into the jointed, web-finned legs of an adult frog (in miniature). Click on image to enlarge and expand view of film strip.
1 & 2. Tadpole rear legs shortly after they first appear. 3 - 5. Within a few days rear legs bend at knee and foot.
American Bullfrog Tadpoles After Front Legs Appear
Tadpole metamorphosis proceeds relatively slowly until the front legs appear. Once that happens, the head begins to quickly, and dramatically, change shape (eyes migrating to top of head). Then the tail begins to reabsorb. Click on image to enlarge and expand view of film strip.
1. Same as 3 - 5 above: Tadpole rear legs shortly after they first bend at the knee and foot. 2 - 4.Tadpole rear legs as they grow and develop. 5. Well-developed tadpole rear legs shortly before front legs appear.
1.Bullfrog tadpole with rear and front legs. Head is just beginning to flatten, changing shape. 2. Bullfrog tadpole with rear and front legs. Eyes are beginning to move toward top of head. 3 - 5. Tadpole head continuing to change shape. Note how mouth is widening from the small mouth of a tadpole to the large mouth of a frog. Photos in order of metamorphosis changes.
American Bullfrog Tadpoles After Metamorphosis
1. Bullfrog tadpole with rear and front legs. Eyes have moved to top of head. 2. Note how pointy the tadpoles head is and how much it looks like the head of a frog. Tail darkening and beginning to be shrink. 3 & 4. Metamorphosis almost complete. Ending with reabsorption of tail. Photos in order of metamorphosis changes.
The SPO Science Image Library is a growing collection of copyright- free science photographs. If you use one of our images, we just ask that you give us credit and provide a link to the SPO website (www.scienceprofonline.com). To save a photo to your computer, right click on it and select "Save".
For those in need of high-resolution images, we will soon be offering hi-res files of many photos in the Science Image Library. Follow us on Twitter @ScienceProfSPO to get updates on new SPO features and products. If you need a high resolution photo now, please contact us.
1 - 3. Tadpole metamorphosis nearly complete with last bit of tail being reabsorbed. 4 & 5. Young, small American bullfrog. Click on image to enlarge and expand view of film strip.