Caves
A cave is defined as an underground
passage large enough for a person to
crawl into, naturally formed, and in
complete darkness.
How does a cave form?
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Rain dissolves Carbon Dioxide into Carbonic acid
Carbonic acid dissolves minerals in rock
Rock is sculpted in weak spots
Water seeps through rocks and makes underground
waterways
When the water level drops, the waterway exits the
rock through the exiting hole (resurgence)
Collections of water creates deep gaps in caves.
When the water level outside the cave drops, the cave
empties and dries out.
Stalactites
• Stalactites
– Formed by water that drops
from the top of the cave
that contains calcite
– The calcite is left when the
water drops
– Constant winds blowing
cause stalactites to grow in
crooked.
– Occasionally, stalactites
will grow together with the
stalagmites and will create
a column.
Stalagmites
• Stalagmites:
– Form from the bottom
of the cave
– They grow about 1 cm
every 1000 years
because it is hard for
water to evaporate in
the moist cave
Types of Stalactites
• Types of
Stalactites
• Icicle
Straw
Drape
Types of Stalagmites
• Dish Stack
Fir Cone
Others
Cave Sections
• Cave environments fall into three basic categories:
1. Endogean: parts of cave that come into contact with
the surface
– Example: cracks, rock seams, groundwater seepage, and root
protrusion
2. Parahypogean: regions near cave mouths that extend
to the last penetration of sunlight.
3. Hypogean: deep in the cave, only come into contact
with the surface through wind, underground rivers, or
the migration of animals.
• Considered to be “true” cave environments
• The deeper the cave becomes, the less biodiversity is
found.
Types of Caves
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Erosional- formed
by the action of
water or wind,
carrying abrasive
particles capable of
carving rock
Types of Caves
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Lava Tube- lava travels beneath the
surface and is expelled by a volcano
during an eruption
Types of Caves
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Sea Caves- form
from wave actions
along the coast
where areas are
weak in sea cliffs
Types of Caves
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Solution Cavesform where rock is
dissolved away
Cave Organisms
• Cave organisms fall into three basic
classes:
1. Troglobites: “cave dwellers” animals that are
specialized for cave life.
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Can leave for short periods of time
Can complete parts of their life cycles above ground
Can’t live entire lives outside of the cave
Examples: some bacteria, some flatworms, and
blindfish
Cave Organisms
2. Troglophiles: “cave lovers” can live
part or all of their lives in caves
– Can complete a life cycle in certain
environments on the surface
– Examples: cave crickets, millipedes,
pseudoscorpions, and spiders
Cave Organisms
3. Trogloxenes: “cave guests”
– Frequents caves
– May require caves for a portion of it’s life
cycle
– Must return to the surface
– Examples: Hibernating reptiles and
mammals
Cave Organisms
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Troglophobes: “cave haters”
Can’t survive in caves for any time period
Example: organisms that fall through
sinkholes or frogs swept into caves by
flash floods
Adaptations of Things that Live in
Caves
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Loss of pigment
Loss of eyes
Blue eyes (can absorb light better)
Elongation of appendages
Enhancement of other senses (can sense
vibrations in water)
• Echolocation
Bats
• Nocturnal
• They sleep in the back of caves to keep from
being eaten
• Are found everywhere except Antarctica and the
Artic
• Hibernate in caves
• When weather is warm, the bats leave the caves
at night to find food
• They are the only mammals that can fly
• Wings are a membrane of skin that stretches
from their body to their fingertips.
Horse-shoe Bats
• Have horseshoe shaped
structure around their
nostrils to help direct
sound for echo location
• They wrap their wings
around themselves to
keep warm during
hibernation
• When they are asleep,
they tuck their wings to
their sides
Bat Communication and Pregnancy
• Pregnant bats move to a warmer area in
the cave to give birth
• When the baby is young, it goes with the
mother to get food
• When it is older, it is left behind and calls
to the mother so she can find her way
back
Where do cave dwellers get food?
• Some get food from outside the cave
• Some eat things inside
– Guano (Bat Poo) falls to the ground where millipedes,
beetles, and fungi get their nourishment
– Dead animals
– Organic debris washes in from streams
– Cave crayfish
– Cave shrimp
– Flatworms
Cave Studies
• Speleology- the scientific study of caves.
• Spelunking- recreational exploring of
caves.
• Cave cartography- creating cave maps
• Cave geology- study of cave rock.
• Cave Hydrology- study of water features
in caves.
Endangered Species
• Tooth cave spider
Endangered Species
• Trapdoor spider
Endangered Species
• Gray Bat