Who laid this?

Identify eggs, egg masses and nests.

Found jelly-like eggs in a pond or ditch, a cluster under a log, leathery eggs in the mulch, or a dug-up nest with curled shells? Answer a few questions about what you can see and this key narrows the possibilities to the frogs, salamanders, turtles, snakes and lizards that actually live where you found them, showing its reasoning at every step. It also tells you when your find may not be a reptile or amphibian egg at all. Skip any question you can’t answer. Free, and in beta.

No AI-generated answers. Built from real sources and fixed rules.What this meansClose

When you use this tool, no AI writes your answer. The result comes from rules we set ahead of time, applied to information gathered from sources such as field guides, scientific records and our own courses. It is not made up on the spot.

AI did help us build it: writing code, organizing information and drafting some of the drawings.

How we build our tools

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How it works

Jelly or shell, then the details.

Frog and salamander eggs have no shell: each one sits in clear jelly, in water or somewhere damp. Reptile eggs have a shell and are laid on land. From there the key asks how the eggs are arranged (strings, round masses, floating films, single eggs), what they are attached to, their size and number, and where and when you found them. Add your location, and the list gets short.

A clutch of white, oval North American Racer eggs in a hollow among pine needles and oak leaves. — A clutch of North American Racer (*Coluber constrictor*) eggs in leaf litter: shelled and laid on land, as reptile eggs are. Photo by Micha Petty.

Look, photograph, leave them

Every question can be answered from a photo. Take one of the whole group and one close up, with a coin for scale, and leave the eggs where they are. If you lifted a log, rock or board to see them, put it back just as it was.

Turned them up while digging?

Eggs found while gardening, mowing or moving mulch are usually reptile eggs. Choose “Eggs with a shell”, and the last screen covers what to do next. Until then, keep each egg the same way up and do not bring them indoors.

What the key can’t do

Eggs can rarely be named to one species by eye, and the eggs of many species have never been described in detail. Treat the result as a short list with the reasoning shown. Only characters backed by a published source can rule a species out; every candidate lists its sources.

Egg characters were compiled from published species accounts and keys, with sources listed on every candidate. Found tadpoles or salamander larvae instead? Try Which Tadpole Is This? To see every species on record for your county, use What Lives Near Me.

Identify tadpoles and larvae See what lives near you

Go deeper

Turn a name into understanding.

The key narrows down who laid the eggs you found. The courses teach how those animals live, how to tell them apart, how to care for them, and how to talk about them with people who are afraid of them. Every course is self-paced and grounded in science; one is free, and the rest are priced to stay within reach.