Breadcrumb Sponge: Facts & Adaptations

Instructor: Lauren Posey

Lauren has taught intermediate reading in an English Language Institute, and she has her Master's degree in Linguistics.

In this lesson, you'll learn about a sponge species known as the breadcrumb sponge. We'll look at facts about its life, and adaptations that help it live in its environment.

The Breadcrumb Sponge

When you hear the word 'sponge', you probably think about the kind of sponge you use for cleaning, right? Actually, there is another kind - an animal! There are many species of sponges, and some of them are very far in feel and appearance from a kitchen sponge. The breadcrumb sponge (Halichondria panicea) is very hard and attaches to rocks, but if you tried to pick it up it would crumble like stale bread. This crumbly texture is where it gets its name. Breadcrumb sponges are quite common. In intertidal areas along the Eastern Atlantic coast, they are actually the most common species of sponge.

Physical Features

Breadcrumb sponges range from green to yellow in color. Despite how crumbly these sponges are when picked up, they are very smooth when attached to rocks. Their body is made up of long pieces of silicon dioxide, which is the substance that makes up glass. Since they essentially have a skeleton of glass spikes, you should be careful if you touch one!

Breadcrumb sponges attach themselves to rocks
Breadcrumb sponge

One characteristic of sponges is that they are covered in holes. They use the holes to push water throughout their body. First, they pull the water in with the help of tiny flagella, or mobile, hair-like tentacles. As they move the water through their body they pull out oxygen and nutrients, and then push the excess water back out through the holes.

Breadcrumb sponges prefer to live in intertidal zones, rather than in the deep ocean. There are more waves and currents in intertidal zones, which means there is more water movement over the sponges. This helps the sponges push water through their bodies and collect nutrients.


Breadcrumb sponges can reproduce both sexually and asexually. Asexual reproduction is achieved through budding. This is when a piece of the sponge grows out and breaks off, becoming a new sponge that is basically identical to the original. The bud floats in the water until it can attach to a suitable surface.

Sexual reproduction occurs when male sponges release their sperm into the water. The sperm fertilize the eggs carried by the female sponges, and the eggs develop inside the female sponge. After they hatch, the larvae, or baby sponges, are released out into the water. They will swim for several months until they find a suitable surface, and then attach and grow into a new breadcrumb sponge.


Intertidal zones can be rough areas to live, with heavy wave pressures and many predators around. However, breadcrumb sponges have a number of adaptations that help them do well in this environment. One is that they have developed symbiotic relationships - which is when two organisms coexist and benefit each other - with two different species. The first is a type of algae known as zoochlorellae. The algae grow on the sponge and provide it with extra nutrients. In return, the sponge provides the algae with a home that is relatively safe from the rough intertidal waters.

Breadcrumb sponges also have a symbiotic relationship with scallops. In this case, it is the sponge that grows over the scallop. Having a sponge on top of it keeps the scallop safe from sea stars (which eat scallops). In return, the sponge receives extra nutrients and water flow as the scallop pulls water in and out of its shell.

Breadcrumb sponges have a symbiotic relationship with scallops such as these

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