Animal Species Recognition with Deep Convolutional Neural Networks from Ecological Camera Trap Images

Animals (Basel). 2023 May 2;13(9):1526. doi: 10.3390/ani13091526.

Abstract

Accurate identification of animal species is necessary to understand biodiversity richness, monitor endangered species, and study the impact of climate change on species distribution within a specific region. Camera traps represent a passive monitoring technique that generates millions of ecological images. The vast numbers of images drive automated ecological analysis as essential, given that manual assessment of large datasets is laborious, time-consuming, and expensive. Deep learning networks have been advanced in the last few years to solve object and species identification tasks in the computer vision domain, providing state-of-the-art results. In our work, we trained and tested machine learning models to classify three animal groups (snakes, lizards, and toads) from camera trap images. We experimented with two pretrained models, VGG16 and ResNet50, and a self-trained convolutional neural network (CNN-1) with varying CNN layers and augmentation parameters. For multiclassification, CNN-1 achieved 72% accuracy, whereas VGG16 reached 87%, and ResNet50 attained 86% accuracy. These results demonstrate that the transfer learning approach outperforms the self-trained model performance. The models showed promising results in identifying species, especially those with challenging body sizes and vegetation.

Keywords: camera trap; convolutional neural network; deep learning; endangered species; image augmentation; image classification; lizard; machine learning; snake; toad.

Grants and funding

This research was funded by the U.S. Fish and Wildlife Service, the Bastrop Utilities HCP, Texas A&M Natural Resources Institute, the Texas Comptroller of Public Accounts, and the Texas Research Incentive Program.