In alligator length estimation, the snout-eye-length is an approximation of length used for some species and speaks about proportionality of growth. For example, each inch length from the eye of the crocodile to the end of the snout equals the length of the alligator. For example 3 inches of snout-eye-length implies that the alligator is 3 foot in length. This estimation works for some species of alligator but implies that all growth is proportional and has a good p-value
https://herpconbio.org/Volume_7/Issue_3/Macip-Rios_etal_2012.pdf
Interestingly, the snout length does change and there has been strong correlation of increased snout length has been observed in domestication across multiple species and human change in facial features may also be ascribed to that “domestication”.
