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Mermaid's Purse

Source Institutions

    Aquarium of the Bay

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Mermaid's Purse

In this activity (page 2 of pdf), learners craft a model of a skate egg case and come to understand that cartilaginous fish such as sharks and shakes employ reproductive strategies that differ from those of mammals. This activity requires 2 days to complete, but only 45-60 minutes per day. Educators can incorporate internet videos or pictures where egg development can be seen. This is also a great activity to accompany a field trip to an aquarium that has a breeding program for sharks or skates, such as Aquarium of the Bay on Pier 39 in San Francisco.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
1 to 7 days

Estimated Materials Cost:
1 cent - $1 per student

Age Range:
Ages 6 - 11

Resource Types:
Activity, Lesson/Lesson Plan, Model


Materials List (per student)

  • Pink construction paper
  • Olive green construction paper
  • Tan, gold or green tissue paper torn into strips
  • Glue
  • Scissors
  • Papier mache paste
  • Paint (optional)
  • Small balloons
  • Newspaper for covering tables
  • Clear plastic wrap
  • Shallow containers to hold paste (disposable aluminum trays work well)


  • Life Sciences
    • Diversity of Life
      • Animals
    • Ecology
      • Biodiversity

Informal Categories

  • Animals
  • Arts and Crafts
  • Model Building
  • Nature and Environment


To use this activity, learners need to:

  • see
  • see color
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Includes alignment to state and/or national standards

This resource is part of:

Access Rights:

  • Free access



  • All Rights Reserved, Aquarium of the Bay,