Litter Critters

In the leaves under our feet is a world teeming with animals. As plants die and drop to the ground, they form a layer of decaying leaves, sticks, and bark called litter. This natural litter layer forms a constantly changing habitat in which many organisms live. Large animals dig through litter in search of food. Rain washes litter away, wind blows it around, and sun dries it out. Where the litter is thick, however, only the upper layers dry out; the layers next to the soil provide a continuously moist environment. In this moist area, tiny organisms such as fungi and bacteria feed on bark, leaves, and twigs, and break them down (decompose) into smaller and smaller pieces. Decomposers also release minerals back into the soil. At the same time that the lower layers are being broken down, new plant material is being deposited on top of the existing layer, ensuring a continuous litter habitat.

Animals that live in litter (for example, insects, slugs, spiders, and salamanders) are generally small. Their small size allows these animals to crawl into tiny crevices between pieces of decomposing plant and animal matter. Their size also makes these animals easy to overlook.

In this outdoor activity, learners use a “litter-critter” wheel to help them identify different animals they find living in a natural litter habitat. Learners also become familiar with body parts of litter habitat animals, and use that knowledge to identify animals they find. This activity addresses the concept of decomposition as well, and can be expanded to address specific aspects of biodiversity across various litter habitats, including those affected by human litter. Depending on the age of the learners, they can make the litter-critter wheels themselves.

Outdoor Biology Instructional Strategies (OBIS) is an outdoor program that offers young people fun and challenging opportunities to investigate ecological relationships in their local environment. OBIS was developed in the 1970s at the Lawrence Hall of Science to help adults (teachers, parents, community leaders) take young people outdoors to experience ecological principles in their local area. We have made several of the original 97 OBIS activities available digitally. These activities, which increase environmental awareness, can be used individually or in combination. These simple experiences then act as a gateway for children and adults to explore and understand their local environment.