Deep in the Jungle: Towards Automating Chimpanzee Population Estimation

Fuente: arXiv
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Autori principali: Raynes, Tom, Brookes, Otto, Haucke, Timm, Bösch, Lukas, Crunchant, Anne-Sophie, Kühl, Hjalmar, Beery, Sara, Mirmehdi, Majid, Burghardt, Tilo
Natura: Preprint
Pubblicazione: 2026
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author Raynes, Tom
Brookes, Otto
Haucke, Timm
Bösch, Lukas
Crunchant, Anne-Sophie
Kühl, Hjalmar
Beery, Sara
Mirmehdi, Majid
Burghardt, Tilo
author_facet Raynes, Tom
Brookes, Otto
Haucke, Timm
Bösch, Lukas
Crunchant, Anne-Sophie
Kühl, Hjalmar
Beery, Sara
Mirmehdi, Majid
Burghardt, Tilo
contents The estimation of abundance and density in unmarked populations of great apes relies on statistical frameworks that require animal-to-camera distance measurements. In practice, acquiring these distances depends on labour-intensive manual interpretation of animal observations across large camera trap video corpora. This study introduces and evaluates an only sparsely explored alternative: the integration of computer vision-based monocular depth estimation (MDE) pipelines directly into ecological camera trap workflows for great ape conservation. Using a real-world dataset of 220 camera trap videos documenting a wild chimpanzee population, we combine two MDE models, Dense Prediction Transformers and Depth Anything, with multiple distance sampling strategies. These components are used to generate detection distance estimates, from which population density and abundance are inferred. Comparative analysis against manually derived ground-truth distances shows that calibrated DPT consistently outperforms Depth Anything. This advantage is observed in both distance estimation accuracy and downstream density and abundance inference. Nevertheless, both models exhibit systematic biases. We show that, given complex forest environments, they tend to overestimate detection distances and consequently underestimate density and abundance relative to conventional manual approaches. We further find that failures in animal detection across distance ranges are a primary factor limiting estimation accuracy. Overall, this work provides a case study that shows MDE-driven camera trap distance sampling is a viable and practical alternative to manual distance estimation. The proposed approach yields population estimates within 22% of those obtained using traditional methods.
format Preprint
id arxiv_https___arxiv_org_abs_2601_22917
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Deep in the Jungle: Towards Automating Chimpanzee Population Estimation
Raynes, Tom
Brookes, Otto
Haucke, Timm
Bösch, Lukas
Crunchant, Anne-Sophie
Kühl, Hjalmar
Beery, Sara
Mirmehdi, Majid
Burghardt, Tilo
Computer Vision and Pattern Recognition
The estimation of abundance and density in unmarked populations of great apes relies on statistical frameworks that require animal-to-camera distance measurements. In practice, acquiring these distances depends on labour-intensive manual interpretation of animal observations across large camera trap video corpora. This study introduces and evaluates an only sparsely explored alternative: the integration of computer vision-based monocular depth estimation (MDE) pipelines directly into ecological camera trap workflows for great ape conservation. Using a real-world dataset of 220 camera trap videos documenting a wild chimpanzee population, we combine two MDE models, Dense Prediction Transformers and Depth Anything, with multiple distance sampling strategies. These components are used to generate detection distance estimates, from which population density and abundance are inferred. Comparative analysis against manually derived ground-truth distances shows that calibrated DPT consistently outperforms Depth Anything. This advantage is observed in both distance estimation accuracy and downstream density and abundance inference. Nevertheless, both models exhibit systematic biases. We show that, given complex forest environments, they tend to overestimate detection distances and consequently underestimate density and abundance relative to conventional manual approaches. We further find that failures in animal detection across distance ranges are a primary factor limiting estimation accuracy. Overall, this work provides a case study that shows MDE-driven camera trap distance sampling is a viable and practical alternative to manual distance estimation. The proposed approach yields population estimates within 22% of those obtained using traditional methods.
title Deep in the Jungle: Towards Automating Chimpanzee Population Estimation
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2601.22917