Tadpole Development

Tadpoles are often difficult to identify because they go through so many different stages in their life time.

From eggs the tadpoles hatch as embryos and quickly transform into free swimming larvae. These larvae undergo many changes themselves in order to transform into a frog. K.A. Gosner created a table for staging anuran embryos and larvae in 1960. This detailed table reveals all of the intricate transformations a tadpole undergoes before metamorphosing into a frog in 46 stages. Although this guide has proven to be most useful for in lab work where a microscope is present our lab has created a simplified version of this table for use in the field in 8 easy stages.

Field Stage 1

All of the stages previous to "Gosner stage 25" are called "field stage 1".Anything younger than tadpoles with developed teeth rows (denticals) or developing limbuds (tadpoles less than stage 25) are nearly impossible to identify. All new hatchlings start out as very small black tadpoles.

 

Field Stage 2

Field Stage 2 is easy to identify once you have identified your first limb bud. Limb buds are not very easy to see at first,they are little white buds where the tail meets the body, not to be confused with the anus or feces of the tadpole. Our stage 2 is equivalent to Gosner stages 26-30.

Field Stage 3

Field Stage 4

Field Stage 5

 

Field Stage 6

Field Stage 7

Field Stage 8

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