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What did you find?
13 step-by-step identification tools, each built around what you can actually see and test rather than what a photograph happens to look like. Pick the one that matches what is in front of you.
What rock is this?Hardness, streak, lustre and cleavage — the tests that actually separate minerals.
Rocks & minerals →
What snake is this?Start with your state. Most have one or two venomous species, and several have none.
Snakes →
What spider is this?Of ~3,500 US species, two groups matter medically. The web narrows it fastest.
Spiders →
What's wrong with my plant?Which plant, what the damage looks like, and whether it started at the bottom or the top.
Plant problems →
What kind of mold is this?The species rarely changes what you should do. Finding the water always does.
Mold →
What mushroom is this?Spore print, what's under the cap, and the base of the stem you have to dig for.
Mushrooms →
What tree is this?Opposite or alternate leaves removes most species before you look at the leaf itself.
Trees →
What fish is this?The confusable pairs, side by side — and a reminder that limits are set by your state.
Fish →
What bird is this?Start with size and bill shape. Colour is the last question, not the first.
Birds →
What is this old thing?How it was made dates it more reliably than what it looks like.
Antiques →
What stamp is this?Country, then printing method, then perforation. Catalogue value comes last.
Stamps →
What breed is my cat?Coat, body type and head shape — and an honest note about mixed breeds.
Cat breeds →
What breed is my dog?Size, coat, ears and muzzle. Most dogs are mixed, and the page says so.
Dog breeds →How this works
The same method in every section, because it is the method that does the work.
Every question is optional. Answer three and the list of possibilities is usually short enough to check by hand.
It varies with age, light, water and season. Shape, arrangement, texture and location do not, which is why the questions ask about those instead.
Where an answer cannot be trusted — a mushroom you intend to eat, a snake in reach, a bite that is spreading — the page says so before it says anything else.
Latest
Across every section. All guides · all articles
- stampsHow the Stamp Was Printed, and How to TellRun a fingertip across the design. Engraved stamps have raised ink you can feel; lithographed ones are flat. That single test separates most printings.
- fishCarp, Sucker or Buffalo? Look at the MouthLarge bottom-feeding fish get called carp indiscriminately. Barbels, mouth position and dorsal fin length separate three unrelated groups.
- mushroomsThe Little Brown Mushrooms Nobody IdentifiesThousands of species, few distinguishing features, and one of them is deadly. Experienced mycologists routinely decline to name them.
- moldIs There Mold in the Ductwork?Ducts are rarely the source. The coil and the drain pan usually are, and cleaning the wrong part is the industry's most common sale.
- plantsGrey Fuzz on Flowers and FruitBotrytis takes hold on dying tissue and moves into healthy tissue from there, which is why dead-heading is a disease control measure.
- spidersThe Spider Sitting on a FlowerNo web, front legs held wide, and often the same colour as the petals it is sitting on. Crab spiders wait rather than hunt.
Questions people ask
Is this free, and do I have to sign up?
Everything on the site is free, with no account and no email. Nothing you select is sent to a server — the identification runs in your browser, which is also why it keeps working after the page has loaded and why there is nothing here that could keep a copy of what you entered.
Why not just use a photo app?
Use both, for different moments. Photo identification is fast and good at distinctive, well-formed specimens. It is weak at exactly the cases people struggle with: worn, damaged, juvenile or partly-hidden things, and lookalikes that differ in a feature the camera cannot see. The questions here work from properties you can test or observe directly, which is what separates the hard cases.
How accurate is it?
It narrows; it does not conclude. Answering three good questions usually takes a list of dozens down to a handful, and the handful is where your own eyes take over. Where being wrong carries a real cost — eating a mushroom, approaching a snake, a bite that is spreading — the page says so before it says anything else, and points at someone qualified.
Why are there eight different subjects on one site?
Because they are one question asked eight ways. Somebody has found a thing — a rock, a snake in the yard, spots on a leaf, something black in the bathroom — and wants to know what it is. The method is the same each time: ask about characters that do not vary, ignore the ones that do, and be honest about where the answer stops.
Who writes this?
An editorial team, and every guide and article carries a byline and a date it was last reviewed. The about page sets out how entries are written, what the site will not do, and how to report something that is wrong — corrections update the review date rather than being made silently.
Are there apps?
Yes — a separate free iPhone app for each subject, which does the part a website cannot: reading a photograph, in the field, with no connection. Each section links to its own. Nothing on this site requires one.