Identifying Your Eggcase

Congratulations on your exciting find(s)! 

We expect you’re eager to find out which species this belongs to! So let’s get started.


We recommend preparing your eggcase(s) by doing a bit of bucket science. Rehydrating eggcases makes them much easier to identify. You’ll also see how much they expand to their true size, and how tough they are to protect the developing embryo!

  • Fill a container with fresh water - you can use anything from a freezer bag to a bucket.

  • Put the eggcase in the water – if possible try to remove all the air so it sinks.

  • Leave to soak for 1-2 hours - the longer it’s been out of water, the longer it’ll need to fully rehydrate. Larger eggcases will need to soak for around 24 hours before they return to their original shape.

  • Remove the eggcase from the water

  • Get cracking with identifying your find!

Once you've identified and photographed your eggcase you can dry them out in a well-ventilated spot. As long as they're empty, they shouldn’t smell.


We've created a handy ID Guide and Key to help you identify your eggcases. You can also download the Shark Trust App and use this to identify and record your eggcase finds. There is a kid friendly eggcase guide and trail, which can be set up at home. So whatever the weather you can learn about and search for eggcases.

App Icon - iPhone App Icon - Android

Great Eggcase Hunt ID Posters for Europe and Mediterranean

English  Welsh Portuguese

Spanish Dutch Turkish

Greek Libyan Tunisian

Eggcase ID Key

English Welsh

Great Eggcase Hunt ID Poster for USA Eastern Seaboard

Great Eggcase Hunt ID Posters for Australia

New South Wales Northern Territory 

Queensland South Australia

Tasmania Victoria Western Australia

Great Eggcase Hunt Leaflet

Great Eggcase Hunt Junior Leaflet


Indoor Easter Eggcase Hunt


Eggcase Junior ID Guide



If you’re having problems identifying your eggcase, it could be because...

  • It’s Broken - Some key features may be missing as eggcase horns and tendrils are delicate and can break easily.

  • Short Horns - If the horns have snapped they'll look a lot shorter than they should. The eggcases of species such as the Small-eyed Ray and Cuckoo Ray have long and delicate horns so may not survive the surf intact.

  • Colour - Don't use colour as an identifying feature. Individual animals have unique characteristics so their eggcases will be slightly different to other animals of the same species. Smallspotted Catshark eggcases in particular can be golden, yellow, dark green, brown, black or even transparent.

  • Attachments - You may notice other organisms attached to the eggcase. Ignore these when making an ID.

  • Misshapen Capsules – Old specimens and eggcases that’ve been dry for a long time may never fully return to their original shape when soaked.

  • Beware Eggcase Imposters - The large air bladders of some species of seaweed are often mistaken for eggcases.

  • Size - Size can vary greatly even within the same species. So, don’t get too caught up if it’s a centimetre or so outside of the size ranges we provide on the ID guide.

Still Having Trouble?

Sometimes eggcases can be tricky to ID, especially if they’re damaged. But we’ve seen a lot of eggcases in our time, and we’re always here to help. If you’re having trouble just send us a photo (or the specimen) and we’ll get our eggcase experts on the case.

Verifying Your Record

Seeing the eggcase, or at least a photo, is important as it enables us to verify your record. So please do send us a photo with your submission. You can do this using our online recording form or via the app (iPhone/Android).

For more detail on identifying eggcases, including an Identify specific video, see our Eggcase Champion Training Guide at


Banner image: James Harris