Dynamite Cave

Click on Map below for a larger image

  • Surveyed Length: 63.1 m
  • Depth: 7.8 m


Dynamite Cave is one of the caves at Colorado Bend State Park. It is short but roomy, and has the largest colony of daddy longlegs harvestmen in the area. Watch out for buzzards!

The cave has one room about 2 to 3 m high, 5 m wide, and 15 m long. A second, small entrance can be seen at the far end of the room. There are some formations and the floor is dry, loose soil.

Dynamite Cave is often visited by tour groups because it has a lot of watchable wildlife for such a short cave. In the summer, the elliptical entrance sink contains a colony of thousands of daddy longlegs harvestmen, Leiobunum townsendii. These creatures are harmless and are not spiders but opilionids, or harvestmen, an eight-legged arachnid Order without poison glands, a one-piece body instead of a distinct abdomen, two eyes instead of the spider's six to eight eyes, and different mating structures. Daddy longlegs are social and bob up and down when alarmed. You may smell a faint, sweet odor, which is secreted by glands on the side of the body; this could be an alarm pheromone or a repellent against predators. This species exits caves after sunset, is a scavenger, and has a mass die-off in the winter but comes back in full force every spring.

Occasionally one can see black vultures in and around this cave. Vulture chicks make scary hissing sounds and mother buzzards get upset with intruders and try to vomit on them. Please leave if vultures are present. Vultures are ecologically important and are protected by law.

Dynamite Cave is a good place to see the red, ant-like Rhadine howdeni beetles, who rapidly run over the soil looking for cricket eggs or nymphs to eat. Look under large rocks and off to the sides of the room. This species has eyes, but other Rhadine species in the Balcones Fault Zone caves are eyeless. There are many Cicurina spiders, which are the white-to-cream-colored hunting spiders patrolling the floor. A gopher snake has been seen on a ledge.

The cave is part of a baseline ecology study at the park.  This cave illustrates that even small caves have ecological diversity and value.

Revised 7/2014; original page author: William R. Elliott. All rights reserved.