An initiative of Earthwatch Institute

  1. Main_pic_zebra4_amber-louise_burberry Zebra Top Shells by AL Burberry
  2. Inset_img_3695_c_gillies-cropped Zebra Top Shell by C Gillies

Zebra Top Shell

Austrocochlea porcata


  • Zebra top shells are a marine snail (mollusc)
  • They have a distinctive black and white striped pattern on their shells and no two individuals are the same (vary from thin to thick stripes).
  • The easiest way to identify if you have a zebra top shell is to pick it up and look underneath at the aperture (where the snail come out), which has a black and white striped rim, white interior and a brown operculum (shell door or lid).
  • Size:  up to 25mm

What to Observe

Search area for 30 minutes and record under the following categories:

  • Abundant - found easily with little searching
  • Frequent - found with minimal searching
  • Rare - only 1 or 2 individuals found with intensive searching
  • Not found - not present during search

ClimateWatch Science Advisor

Zebra top shells, like all marine snails (molluscs), are under increasing stress due to ocean acidification which can weaken their calcium carbonate shells and reduce body condition. This makes them more prone to disease, predation and low reproduction. Increasing water temperature as a result of climate change will likely affect their abundance and cause a southward shift in their distribution.

When To Look

Throughout the year.

Where To Look

  • Common on rocky shores, from mid to low tide levels. Usually found in rock pools and wet areas.
  • Geraldton WA, SA, TAS, NSW up to Townsville QLD.


Davey, K. (1998). A Photographic Guide to Seashore Life of Australia. New Holland Publishers Australia Pty Ltd.

Edger, GJ. (2008). Australian Marine Life. The Plants and Animals of Temperate Waters [2nd Ed]. New Holland Publishers Australia Pty Ltd.



  1. Search Species

  1. What Else?

    Zebra top shells can look similar to ribbed top shells (Austrocochlea constricta), which have a grey or off-white coloured shell with 5 or 6 distinctive ridges, spiralling up towards the sharp tip (apex). Ribbed top shells have no striped patterns but may have a dark edge to the ridges. Zebra shells may also resemble the striped coniwinkle (Bembicium nanum) which is also common on intertidal shores and has a similar distribution. B. nanum can be distinguished from the zebra top shell by its flat bottom. The striped pattern occurs only on the first whirl in contrast to the zebras top shell which has stripes on at least two whirls. 

  1. Did You Know?

    Zebra top shells are herbivores and scrape algae from the rock with a specialised rasping tongue called a radula.

    The black and white strips occur due to the snail’s diet. At certain times of the year the algae they eat contains a substance that causes colouration in the shell.