# Morphometric Analysis of the Common Raccoon Dog (Nyctereutes procyonoides) Teeth in Lithuania

## TL;DR

This study examines raccoon dog teeth in Lithuania to determine if there are sex differences and how teeth measurements correlate.

## Contribution

The study identifies canine teeth as showing the most significant sexual dimorphism in raccoon dogs, offering new insights for zooarchaeological research.

## Key findings

- Canine teeth showed the most significant sex differences among raccoon dogs.
- Upper teeth and tooth rows had stronger correlations than lower ones.
- Molars and tooth rows are not reliable for sex determination in raccoon dogs.

## Abstract

The raccoon dog is one of the most widespread invasive members of the canine family. However, its teeth have received less attention in morphometric studies compared to the skull. This study aimed to measure canine and molar teeth, as well as tooth rows, to identify potential differences between males and females. Additionally, we analyzed the correlation between different teeth and tooth row measurements. The results showed that teeth differences between sexes were minimal, with the most significant variation found in canine teeth. Tooth row measurements did not differ between sexes. Furthermore, we observed that upper teeth and tooth rows had stronger correlations than lower ones.

Sex identification is often challenging, especially when only skeletal remains are available. While previous research has primarily focused on skull measurements, dental traits have received less attention. This study aimed to measure the upper and lower canines, molars, and tooth rows of raccoon dogs in Lithuania to examine sexual dimorphism and analyze the correlation between different teeth and tooth row measurements. A total of 90 skulls with lower jaws of adult raccoon dogs were examined, including 55 males and 35 females. Osteometric analysis followed standard protocols, with canine measurements adapted using a method tailored to the dentition of carnivorous species. Of all the study measurements, the canine teeth demonstrated the most significant sex differences. The correlation analysis showed a strong correlation (p < 0.001) between the dimensions of the upper molars P4, M1, and M2. The upper tooth rows were strongly correlated (p < 0.001) with the dimensions of the P4 and canines. Lower molar correlations were weaker than upper ones, and lower tooth rows showed less correlation with tooth measurements. These findings indicate that molars and tooth rows are not reliable for sex determination in raccoon dogs. However, the observed sexual dimorphism in canine teeth may offer insights for future zooarchaeological and comparative anatomical studies.