If the bacteria associated with the longer toad is opportunistic, then it is likely to be selected against over time. Long toads may have an advantage in colonization, but if short toads are more successful reproductivly, they will eventually predominate. Evolution moves toward breeding success. However, if that particular species of bacteria was present in the new territories and has found a new host in which it causes the arthritis, then it might represent a control tool. The question is: Does the bacteria attack arthritic toads or cause arthritis in toads? Ancillary issue: if the bacteria is causing the arthritis, instead of taking advantage of it, it might represent a research direction for human arthritis.