dcher95/inat-coobserved

iNat Co-Observed — multi-species benchmark (iNaturalist, TOL-200M held-out)

dcher95/inat-coobserved

5,996 photographs, each containing two organisms of different species — both identified to research grade by the iNaturalist community — with every photo absent from TreeOfLife-200M. Built to evaluate steered multi-species identification in biological vision–language models: given the image and a partial taxonomy of one organism (its lineage down to the rank at which the two organisms diverge), recover the rest of that organism's lineage.

How it was built

1. Source. iNaturalist open-data metadata export of 2026-08-27 (488.6 M photos, openly licensed only). When an observer uploads the same photograph as two observations of different species (host + parasite, flower + pollinator, two birds in frame), iNaturalist attaches the same photo_id to both. 646,598 such photos exist platform-wide; we verified on a sample via the iNaturalist API that the bytes reached through each observation are identical.
2. Pool. Photos with exactly two observations, both research grade, both identified to species, full 7-rank lineages (from taxa.ancestry), kingdoms Animalia/Plantae/Fungi.
3. Held-out. All iNaturalist photo_ids appearing in TreeOfLife-200M's source_url (69,601,524 distinct) removed. TOL-200M's iNat snapshot ends in early 2024, so this is largely a temporal holdout (3,499 photos observed in 2024 or later).
4. Licenses. CC0, CC-BY and CC-BY-NC photos only (ND and SA excluded).
5. Stratified sample. 1,000 photos per divergence rank — the first rank at which the two lineages differ — for kingdom, phylum, class, order, family and genus (species-divergence excluded: a hint at species leaves nothing to predict). Within a stratum, round-robin over kingdom pairs, then class pairs; ≤5 photos per species, ≤10 per observer; seeded and reproducible. 4 photos whose files were no longer served were dropped.

divergence rank	kingdom	phylum	class	order	family	genus
photos	1000	1000	998	999	1000	999

6,557 species · 561 class pairs · 10,331 distinct observations (1,390 photos share their observation pair with another photo, i.e. same two organisms, different frame — see n_photos_sharing_observation_pair). Kingdom pairs: Animalia + Animalia 2842, Plantae + Plantae 1746, Fungi + Fungi 408, Animalia + Fungi 334, Animalia + Plantae 333, Fungi + Plantae 333. 815 of 11,992 species slots are species that never appear in TOL-200M under any photo (species_in_tol200m).

Schema

One row per photo. organisms holds the two organisms (order is arbitrary — the task is symmetric; each can serve as the target).

column	notes
photo_id, photo_uuid, photo_page_url	iNaturalist photo identifiers
image	medium rendition (JPEG, longest side ≤ 500 px typical); image_url = original, image_url_medium = what is embedded; image_sha256 of the embedded bytes
license, license_url, attribution	per-photo Creative Commons license as set by the photographer; ready-made credit line
observer_id, observer_login, observer_name	photographer
observed_on, latitude, longitude, positional_accuracy_m	from the observation (coordinates as published by iNaturalist; may be obscured for sensitive taxa)
divergence_rank	first rank at which the two lineages differ (kingdom … genus)
kingdom_pair, class_pair	e.g. Animalia + Plantae, Insecta + Magnoliopsida
organisms[i].observation_uuid, observation_url, taxon_id, taxon_url	iNaturalist observation and taxon identifiers
organisms[i].kingdom … species, scientific_name	7-rank lineage from the iNaturalist taxonomy at export time; species is the binomial
organisms[i].quality_grade	research for all
organisms[i].species_in_tol200m	whether this species occurs anywhere in TOL-200M (photo-level exclusion holds regardless)
in_tol200m	always false — asserted at build

Caveats

• Both labels are community identifications at export time (2026-08-27); identifications can change.
• The second organism can be small or distant. Coordinates are as published (possibly obscured). Observations with all-rights-reserved photos are absent from the source export by construction.

Attribution and license

Every image is © its photographer and released under the license in its license column (CC0, CC-BY 4.0 or CC-BY-NC 4.0) via iNaturalist. Use the attribution string when displaying an image. The metadata compilation is released under CC0. Non-commercial use only for CC-BY-NC photos.