Newborn IgW and IgM CDR3 are significantly shorter than the adult correlate. A). Newborn and adult nurse sharks (Gc) frequency of specific CDR3 region lengths for IgM, IgW and IgNAR were compared. Newborn VH CDR3 is shorter in length more frequently than the adult for each Ig isotype except IgNAR type 3 (which is not expressed in detectable amounts in the adult). Sample size for each Ig isotype in newborns and adults are listed in part B. B). The mean CDR3 lengths for Xenopus laevis (Xl) [49,51] and human (Hs)  newborn and adult IgM VH sequences were compared to the newborn and adult shark IgM, IgW and IgNAR VH CDR3 mean lengths. Significantly the newborn shark CDR3 lengths for each Ig class follow the same pattern of preference for shorter CDR3 lengths as seen in the newborn frog (larvae) and human. Significance determined by ANOVA test with ** = p value <0.01 and * = p value <0.05.