Stuart Bat Cave

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  • Length: 331.8 m (1,089 ft.)
  • Vertical Extent: 28.8 m (94.5 ft.)
  • Special Instructions: Bat flight viewing is available to the public in the evening for a small fee. (See
  • Directions: Go 23 miles north from Brackettville on 624. Turn left at the Kickapoo Caverns State Natural Area entrance left and drive down the dirt road west 1.1 mi. to a fence. The cave is on the hillside to the left, but visitors may not visit the cave on their own. Continue to the park headquarters for information about tours.


Stuart Cave (formerly known as Green Cave - see map) is a single, 332-m-long passage that averages 20 m wide by 8 m high. It contains a world of guano and gnats.

The cave begins as a steep, slippery ramp, leading down into a 17 m wide by 6 m high passage. Passage dimensions begin to change almost immediately and vary throughout the length of the cave; heights range from 1.8 to 14.6 m and widths from 7 to 18 m. The passage is seldom less than huge. Much of the cave floor is covered with breakdown and bat guano. Massive columns and other speleothems occur throughout the cave, although most are stained and partially covered by guano. A decorated and relatively guano-free alcove can be found about 80 m into the cave. Some modest but clean stalactites occur in the room at the end of the cave.

Stuart Bat Cave has been known since the 19th century, but most visits were side trips from its more popular and famous neighbor, Kickapoo Cavern. Consequently little historical information has been recorded on this overshadowed cave. The cave was mined for guano for many years up to at least 1957. Miners dug a shaft from the surface into Stylolite Hall near the back of the cave. It was covered by the Texas Parks and Wildlife Department (TPWD) in 1989 to return the cave to its natural state and encourage growth of the bat colony. A few artifacts from the mining remain in Stuart.

The cave's bat colony is mostly comprised of the Mexican Free-tail Tadarida brasiliensis mexicana. Since TPWD's covering of the shaft entrance the bat population has noticeably increased and is estimated at 500,000. However, the present cover on the shaft is temporary, and an air-tight cover is planned, which would increase the cave's temperature making it more suitable for a maternity colony. Besides the bats, other flying creatures which inhabit the cave include bees and cave swallows (Hirundo fulva pallida) which nest near the entrance, and several million gnats which swarm through the cave during the months the bats are present. The invertebrate fauna has not been well investigated but preliminary collections yield a typical array of guanophiles. The twilight zone contains Rhadine howdeni, a fast-moving reddish, ant-like beetle.

Stuart Bat Cave formed by slow-circulating phreatic groundwater (water contained in and flowing through rock aquifers) which dissolved open large passages within the Devils River Limestone. As the regional water table declined, water drained from the cave, and its ceiling began to collapse into a more structurally stable configuration. The only intact portion of phreatic passage is at the base of the entrance ramp. The downcutting of surface valleys (when surface rock is dissolved away through the effects of wind, rain, and/or flowing water) has twice intersected the cave, once to form its entrance and once at its opposite end to block-off further exploration. Although some of the cave's smaller speleothems are relatively new, dating of the large speleothems indicate their most recent deposits are about 256,000 years old, and most are older than 350,000 years. The last big room in the cave, Stylolite Hall is named for a type of geologic feature seldom seen in Texas caves. Stylolites are bedrock solution features unrelated to the cave's development, which appear in place of bedding planes as undulating to spiked lines. They are best seen in the northwest corner of the room near the terminal breakdown.


Smith, A. R., and J. R. Reddell. 1965. The caves of Kinney County. Texas Speleol. Surv., 2(7):11,13,14.

Stuart, D. K. 1993. Personal communication. Superintendent of Kickapoo Caverns and Devil's Sinkhole State Natural areas.

Veni, G. 1992. An introduction to the age of Texas caves. Texas Caver, 37(5):82-83; reprinted in GEO², 1992, 20(10):3-4 and cover.

Wahl, R. 1988. Personal communication. Austin, Texas.

Revised 7/2014; original page author: George Veni. All rights reserved.