The View from Here


Creatures of the Underworld
April 24, 2009, 11:21 am
Filed under: Caves

My explorations and appreciation of caves is not limited to the geology. Caves are certainly not devoid of life, especially near the entrance. Bats are the most famous inhabitants of caves, a common fixture in Hollywood versions. I have indeed encountered Vampire bats in caves, but only in Central America. No, they didn’t attack. They are creatures of stealth, preferring to quietly open a vein on their victim, using teeth so sharp that it doesn’t wake a sleeping cow or human.  Their guano is truly disgusting. Unlike the relatively inoffensive compost left by insect and fruit-eating bats, Vampire guano is digested blood, resembling a pool of chocolate sauce, but smelling like… well, it is indescribably nasty.
Caves in Kentucky are a bit more tame than tropical caves. Although there may be fairly large bat colonies in some North American caves, especially in the southwest, most bat colonies in the midwest are limited to a few thousand individual bats at most.( These days, our local bat colonies are under threat from White Nose Syndrome, a poorly understood fungal infection that is wiping out colonies in the northeast.) A tropical bat colony’s guano piles are intensely alive, seething with roaches and other insects and arachnids.
The bats support a whole ecosystem of other creatures that live on the bat guano or those that eat the bat guano. Cave crickets, Cave salamanders, millipedes, cave beetles and cave spiders are common. Seen less often are aquatic critters like blind cave fish and cave crayfish. These are highly specialized creatures, unable to survive outside of the cave environment.

A Cave Crayfish--no pigment, no eyes

A Cave Crayfish--no pigment, no eyes

A blind cave fish from Pulaski County, KY

A blind cave fish from Pulaski County, KY

These animals live in a world of perpetual blackness. Beyond the twilight zone near the entrance, the darkness is absolute. Even powerful light amplification equipment will detect no light. So it is no surprise that permanent troglobitic animals have no eyes or pigment. There would be no use at all for these features. They feel their way through their world, using extra long antennae, or sensitive nerves tuned to the slightest vibrations. They are able to live on minimal diets in a very lean ecosystem.

Cave Salamanders live near the entrance zone, where their insect prey is more plentiful

Cave Salamanders live near the entrance zone, where their insect prey is more plentiful

Cave crickets live near entrance zones, and leave the cave at night to feed

Cave crickets live near entrance zones, and leave the cave at night to feed

We were exploring a small cave in Kentucky that we had to excavate a bit to get into. Sediments had blocked the entrance leaving only a tiny hole blowing air. The airflow indicated a sizable cave, so we set about enlarging the entrance. Once I was able to squeeze my head and shoulders into the hole, I saw thousands of cave crickets, covering the walls and ceiling. Crawling into that cramped space with so many crickets would have meant having them literally in your face, and nose, ears, and mouth. We decided to come back at another time. Apparently we found the crickets queing up for their nightly foray onto the forest floor to eat.  In Yucatan, we got to experience a  major bat flight, similar to the one at Carlsbad Caverns in the US, where multiple thousands of bats fly out of the cave.   We were inside a large room with an opening at the top. The bats began gathering as dusk approached, flying in circles around the room as more and more bats accumulated.  Eventually the black cloud of living mammals spiraled out the opening. We sat on the floor looking straight up into the swirling bats. Awesome!

A solitary hibernating Pipistrel bat, covered with condensation.

A solitary, hibernating Pipistrel bat covered with condensation.
"Still Life with Cricket"  20 x15 acrylic on panel

"Still Life with Cricket" 20 x15 acrylic on panel

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