Although allen's and bergmann's rules often explain body shape and morphology, we occasionally see variations from the excepted patterns. what does this sometimes indicate?

This indicates that the body shape and morphology reveal both evolutionary and developmental procedures.

Morphology is a branch of biological science relating to the research of the shape and structure of life forms and their particular basic features. This incorporates parts of the outward appearance like shape, structure, shading, design, measure etc. which is outer morphology, and the frame and structure of the interior parts like bones and organs, meaning interior morphology.

can you explain it better