Egér Hole

The Mouse Hole is one of the caves located in the Aggtelek National Park. Together with the other caves of the Aggtelek Karst and the Slovak Karst, the cave has been part of the World Heritage since 1995.

Description

Along the road from Szögliget to Derenk, 2.95 kilometres from the interior of Szögliget, after a characteristic serpent bend that turns back on itself, 500 metres from there, in a gently but completely left‑turning, westward curve, north of the road, to the right, 35 metres high, above the occasionally active spring, it opens between the rocks. North of the centre of Szögliget, at Derenk, west‑northwest of Szádvar, at 285°, 500 metres away, on a mountain slope, in a rock cleft, in a forest, is the triangular‑shaped, natural, 70 centimetre wide, 1.1 metre high, horizontally oriented entrance. It can be seen only from close up. Some tourist maps mark its location with a cave symbol. It is situated 44 metres east, to the right of the Szádvar cave.

It formed in Upper Triassic Hallstatt limestone. The inactive spring cave developed along tectonic fractures under the influence of flowing water. The typical cross‑section types of the horizontal cave are the fissure cross‑section and the tunnel cross‑section. The branching, space‑shaped cavity is on average 0.5–1 metre wide and 1–2 metres high. The walls of the passages are often decorated with small speleothem formations, stalactite flows, stalactite encrustations. Meanders, spherical chambers, sinuous passages, siphons and breccia zones are also observable. Bone remains were found in the extracted sediment fill. In the narrower fissure passages, a few places in the inner sections are divided by a speleothem floor level, indicating intermittent activity of the cave. Most of its known passages became known as a result of dismantling.

Moles and other mammals are often found in it. Its greatest horizontal extent is 55.2 metres. In the steep terrain, difficult to access, unsealed, easily traversable with basic cave‑walking equipment, the cave is freely visitable.

The cave also occurs in literature under the names Egérluk cave (Kovács 1996) and Egérlyuk (Kovács 1994). In 1998 the cave was first called Egér-lyuk in its literature.

Research history

The cave’s name is not mentioned in the 1984 book *Caves of Hungary*, nor in the national cave list. In 1994 the Vass Imre Cave Exploration Group discovered during a field survey the cave’s human‑inaccessible, narrow entrance section. In 1995 the group opened the cave for about 25–30 m in length. That year the group members built a small climbing track in the horizontal cave to facilitate the exploration of the passage that was almost completely filled with sediment. Because of this, even a small team could work efficiently in the passage. Since 1995 the cave, together with the other caves of the Aggtelek Karst and the Slovak Karst, has been part of the World Heritage.

On 2 December 1998 Attila Nyerges, Lénárd Szabó and Zoltán Szabó produced the cave’s plan map and ten cross‑section maps. The plan map shows the location of the ten cross‑sections within the cave. According to the survey the cave opens at an altitude of 365 m above sea level, is 120 m long and 8 m high. According to the cave’s 1998 registration sheet, the Egér-lyuk located on the northern side of Alsó‑hegy is 102.8 m long, has a vertical extent of 6.14 m, is 5.6 m high and 0.54 m deep. It contains a 34 m long “L”‑shaped iron rail used for dismantling and about 40 m of telephone rope.

In the book about the karst phenomena of Alsó-hegy published in 2019, it is stated that the Egér-lyuk is 120 m long and 5 m deep. The cave identification numbers are: in Slovakia 051, in Hungary 5451/18. The cave maps created in 1998 were published in the book. The cave was surveyed in 1998 by Attila Nyerges, Lénárd Szabó and Zoltán Szabó, who then drew the cave maps based on the survey in 1998. The maps were digitized in 2016 by Luděk Vlk. A detailed map of Alsó-hegy was attached to the publication. The map was prepared by Luděk Vlk, Mojmír Záviška, Ctirad Piskač, Jiřina Novotná, Miloš Novotný and Martin Mandel. On the map, where caves and sinkholes are marked with black dots, the geographical location of Egér-lyuk (5451/18, 051) can be seen.