Students will learn to:
Many species of animals live in caverns or use them for shelter. There are three categories of cavern inhabitants based on the level of their use of a cavern:
Trogloxenes (derived from the Greek words – troglos meaning cavern and xenos meaning guest)
These are animals who normally live outside, but use a cavern for temporary shelter.
Troglophiles (derived from the Greek words – troglos meaning cavern and phileo meaning love)
These are animals that can and often do live outside in a similar environment (cool, dark and moist) but can also live in a cavern if they choose. Some of these animals may choose to spend their whole life inside a cavern.
Troglobites (derived from the Greek words – troglos meaning cavern and bios meaning life)
These are animals that live exclusively in the dark zone of caverns. These animals evolved through the millennia from troglophiles who first entered the cavern and either chose to stay or were trapped and managed to adapt. Through evolution these troglophiles changed their physical attributes to better adapt to the environment. These are the animals which have little or no skin pigment, no eyes and which exhibit other special adaptations.
Zonation is the term used to identify which animals live in which zone.
Cavern inhabitants are also identified by the surface area they occupy in a cavern, whether it be on the ceiling, walls or floor. Different animals inhabit different areas. This is known as stratification.
Identifying animals by stratisphere and zone is known as segregation. This segregation creates small communities of animals throughout a cavern system. A chart is helpful to compare how animals are divided according to stratification and zonation to form a community. An example chart is shown below.
All of the Sierra Nevada Recreation Corporation caverns exhibit some cavern life. However, none of them are heavily populated, and what life there is, is rarely seen. Because of their horizontal entrances, Boyden and California Cavern get occasional visits from bats. However, there are no bat colonies that make these caverns their home. All three caverns have frogs that find their way in from time-to-time. Insect life, though infrequent is the main variety of cave life to be found at the three caverns.
Ahead of time, find suitable rocks outside that can be easily overturned.
Divide the students into small groups. Taking them outside, have each group turn over a rock and be prepared to immediately watch what types of bugs scurry away and where they go. Also note what else is found under the rock. After studying the animal life, have the students think about why the bugs live under the rock (dark, cool, moist) and compare these to living conditions to those in a cavern. Explain that many of the bugs they have been watching (and others of their species) can and do live quite comfortably in a cavern.
List the communities of a cavern system and describe physical characteristics of the animals that live in each one.
Match animals to the appropriate area of the cavern system they live in using the “Inhabitants” worksheet included.
Divide the class into three groups. Each group will study a different zone and the animals found there. When research is complete, have each group share their findings.
Do further study on cavern life concentrating on how cavern animals respond to biological clocks that correspond with outside animals, even though they do not have sunlight or weather conditions to guide them.