Bufo americanus from tadpole to toadlet
- B. americanus home
- Breeding in pictures
- Life cycle from embryo to adult in Gosner stages
- From tadpole to toadlet in pictures
- B. americanus predators
- More pictures and videos of American toad
Bufo americanus from tadpole to toadlet in pictures
Brief facts about tadpoles
Tadpoles of B. americanus are gregarious. They move about extensively and spend much of their time in distinct and cohesive groups called aggregations that are classified into two broad categories: stationary aggregations and moving aggregations. Tadpoles also engage in two types of behavior: butting and coordinated swimming.
Tadpoles begin feeding at Gosner stage 25. They eat detritus, filamentous algae, dead animals including dead conspecifics, gauge out tissue and graze periphyton from stems and leaves of aquatic plants. They also can swim upside down (especially on later developmental stages) skimming floating and suspended particles. Feeding ceases at stage 42 when forelimbs emerge and metamorphic climax begins.
Tadpoles' husbandry
Tadpoles shown here (approx. 60 individuals) were collected in one of Maryland (United States) lakes approximately at Gosner stages 23 - 25 on April 15th, 2010. For Gosner stages reference click here (opens in new window). Therefore, approximately one week passed between breeding peak (observed on April 3rd and 4th) and hatching (occurs around Gosner stage 20).
Tadpoles were housed in 10 gallon tank filled with 3-4 inches of filtered and dechlorinated water (a variety of dechlorinating solutions can be found in pet stores). The water was partially changed (at least 25%) daily. Tadpoles were fed Spirulina Algae Flake Food (NUTRAFIN), BloodWorms Freeze Dried Treat (TETRA), and Tubifex Worms (WARDLEY) purchased at PETSMART (a pet store chain).
Leaves of microalgae covered Amazon sword plant from a tropical fish tank were placed into the water to provide live food supplement and resting surface for developing tadpoles. Early tadpoles rasped holes in the leaves and foraged on the detritus accumulated on the bottom of the tank.
As their development advanced, tadpoles were becoming more voracious and more carnivorous preferring protein-rich food such as dried worms.
Tadpoles varied greatly in size and developmental progression. The two smallest and weakest died between April 15th and May 3rd. The carcasses were not eaten by other tadpoles, hence necrophagous canniballistic behavior frequently reported in literature was not observed.
Tadpoles that completed metamorphosis were released at the original hatching/collection site.
Observing metamorphosis (April - May, 2010)
Tadpoles at stages 23-25: fins transparent, no signs of external gills, eyes are clearly discernable.
4/16/2010
4/16/2010
Tadpoles passed Gosner stage 25: active feeding.
4/20/2010
Tadpoles grew up noticeably. During this period, their oral disc and labial tooth rows differentiated and they progressively became vigorous foragers.
4/24/2010
This tadpole is on Gosner stage 30-31 (foot is "paddle-shaped", no individual toes).
4/25/2010
These tadpoles' spiracles are clearly visible. As in most North American tadpoles (except for microhylids), spiracle is located on the left side of the tadpole.
4/25/2010
Majority of tadpoles aggregate in one dominant group. They exhibit great differences in developmental stages.
4/28/2010
Hind leg's toes are on advanced stage of differentiation in this tadpole.
5/02/2010
Tadpoles: the individual on the left is foraging upside down.
5/03/2010
The only runner up in metamorphic advancements. This tadpole is past Gosner stage 42 (appearance of forelimbs).
5/07/2010
5/08/2010
This tadpole is on stage 40-41. Forelimbs appear at stage 42 at which point tadpoles cease feeding.
5/08/2010
5/09/2010
5/09/2010
Advanced resorption of the tail is evident in our runner-up, whom we started to distinguish individually from 5/07/10.
5/10/2010
This tadpole completed its metamorphosis (at stage 46). It was first one among 50-60 initially captured individuals. Note 1-2 warts per spot characteristic to B. americanus (vs. B. fowleri that have 3-5 warts per spot).
5/11/2010
5/11/2010
5/11/2010
5/11/2010
5/11/2010
5/12/2010
On May 12, three more toadlets came out of water. This tadpole has darker coloration compared with the one who metamorphosed first and, probably, is of another species of toad or frog, which we did not identified.
5/12/2010
On May 14th, four more toadlets came out of water. Ready to be released...
After that, 2-3 metamorphosed amphibians have been released everyday.
Last metamorphosed toadlet or froglet (dark-colored) was released on May 28th.
In 2010, mass dispersal of Bufo americanus toadlets in their natural habitat started on May 26th and continued until about May 29th.
5/14/2010
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