Degree Name

Master of Science (MS)

Semester of Degree Completion


Thesis Director

Kipp C. Kruse


A skelettochronological technique was applied to the phalanges of the American toad, Bufo americanus, from east central, IL. In hematoxylin-stained cross-sections of the phalanges, suspected year rings are formed which can be used to age individuals. This method allows for aging without destructive sampling of toad populations.

A majority of the male toads from two choruses were estimated to be 2 or 3 years old, while most of the females from the same two sites were in the 3 or 4 year age class. Females were larger than males in the 3 and 4 year age classes, and overall, female length was found to be greater than male length. Considerable overlaps were found between the lengths and estimated age classes of both male and female toads. Because of the large variance of size within an age class, it appears that it is not possible to assume that a larger individual is necessarily older.

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