Prediction of total skin length in Nile crocodiles (Crocodylus niloticus) using measurable skin traits

Abstract Nile crocodiles are common in South Africa, reaching up to 6m in total length. The objectives of this study were (1) to determine the phenotypic correlation between total skin length and other measurable skin traits, and (2) to derive a model for predicting total skin length of Nile crocodile. 180 skins were used to measure total skin length and skin traits viz skin weight (SW), skin thickness (ST), neck total length (NTL), neck width at the top (NWT), neck width at the middle (NWM), belly width (BW), belly length (BL), total tail Length (TTL), tail length from the middle (TLM), and Tail width (TLW). Data analysis was computed using Pearson’s correlation, Simple linear regression and stepwise multiple regression techniques in Statistical Package for Social Sciences (SPSS) software version 29.0. Highly positive correlations (P<0.01) were found between total skin length and SW (0.81), BL (0.79), BW (0.75), TTL (0.87), TLM (0.78), TLW (0.48), NTL (0.37), NWT (0.51) and NWM (0.60). High positive correlations (P<0.05) were found between TSL and ST (0.17). Linear regression findings showed that TTL (R2 = 0.76) was the best trait to predict TSL. Furthermore, regression findings showed that a combination of (ST, BL, BW, TTL, TLM, TLW, NTL, NWT, NWM (R2 = 0.90; RMSE = 14.23) was the best in predicting TSL of Nile crocodiles. The results suggest the traits, particularly TTL, can be used as a selection criterion for improving total skin length in Nile crocodiles.