Why I built it
My girlfriend asked me which venomous spiders live in South Carolina, where we live, and I realised there wasn't a good way to show her. Many of the "guides" I found were inaccurate, and plenty of them exist to sell pest control. None of them let you look at an area on a map, which was what I wanted to show her. So I built one for her.
It answers her question the way I wanted to: South Carolina's list has the southern black widow, the northern black widow, and the brown widow. The brown recluse, which a lot of pest-control pages warn about, isn't on it, and the atlas shows the published sources for leaving it out.
What it does
- A map you can explore. Every country, and the states and provinces of the largest ones, shaded by how many venomous species live there. Pick a place to see what's found in it, or pick an animal to see where it lives.
- Where they've actually been seen. Each species shows dots for its recorded sightings, so a big state or a whole coastline narrows down to the areas that matter. Sea animals are drawn by where they've been recorded in the water, not across whole countries.
- Sources for everything. Every species page lists what supports each place it's found in: GBIF records, a checklist, or a cited paper. Places left out on purpose are listed too, with the reason and the source.
- Filters that answer real questions. Narrow it by group (snakes, spiders, scorpions, jellyfish, and more), by how dangerous an animal is, or by name, and share the exact view as a link.
- Built for phones. It installs like an app and keeps working offline for anything you've already looked at, which is handy on a trail with no signal.
How it's built
- Data first. Each species is one small file: what it is, what its venom does, and where it lives. The build validates every file, and fails if any place listed has no source behind it.
- Ranges from real records. A script asksGBIF where each animal has been recorded, about 3.5 million records in all, and proposes places from them. I review every proposal. So far that's 203 places added and 518 removed by hand, each with a citation, from sources such as the Reptile Database, Catalogue of Life, and published papers.
- A map with nothing to pay for. MapLibre draws the map from open boundary files from Natural Earth. There's no tile server, no API key, and no account.
- A static site. It's plain files served by Cloudflare, with no server or database, so it's fast, cheap to run, and keeps working as long as the files exist.
Try it
Open venom-atlas.benjweaver.dev and pick a place, or look up an animal. It's for education, not medical advice: if you're bitten or stung, call your local emergency number.
Spotted a range that's wrong? Open an issue with a source, and I'll check it. The code is free software under the GPL, and the species data is CC BY-SA.