Donji Grahovljani, Hrvatska

Na području Pakračke gore 2006. godine otkrivene su dvije nove špilje: Rastik, dužine 140 metara, te Trbušnjak, duga najmanje 200 metara, a već su prva mjerenja pokazala da je Trbušnjak dužinom nadmašila dosadašnju rekorderku, Uviraljku, i postala najdužom špiljom u Slavoniji. Visina špilje je 3-4 m.

Zbog protjecanja potoka vlažnost zraka u špilji je relativno visoka, temperatura je ljeti i zimi oko 12 ºC. Posebna je vrijednost špilje Trbušnjak ipak to što se u njoj nalazi veliko stanište šišmiša, među kojima su i dvije rijetke i zaštićene vrste, veliki šišmiš (Myotis myotis) i dugokrili pršnjak (Miniopterus schreibersi).

To je ujedno najveća porodiljna kolonija šišmiša u Hrvatskoj i jedna od najvećih u Europi, jer se procjenjuje da velikih šišmiša ima oko 8000, a dugokrilnih pršnjaka čak oko 22.000. Osim njih, u špilji povremeno borave, porađaju se ili prezimljavaju i riđi šišmiš te velikouhi šišmiš, veliki potkovnjak, sivi dugoušan i širkouhi mračnjak.

Donji Grahovljani, Croatia

In the area of ​​Pakračka gora in 2006, two new caves were discovered: Rastik, 140 meters long, and Trbušnjak, at least 200 meters long, and the first measurements showed that Trbušnjak surpassed the previous record holder, Uviraljka, and became the longest cave in Slavonia. Height of the cave is 3-4 m.

Due to the flow of the stream, the humidity in the cave is relatively high, the temperature in summer and winter is around 12 ºC. The special value of the Trbušnjak cave is that it has a large bat habitat, including two rare and protected species, the large bat (Myotis myotis) and the long-winged bat (Miniopterus schreibersi).

It is also the largest maternity colony of bats in Croatia and one of the largest in Europe, because it is estimated that there are about 8,000 large bats and as many as 22,000 long-winged bats. In addition to them, red bats and large-eared bats, large horseshoe bats, gray long-eared bats and wide-eared bats also occasionally stay in the cave, give birth or overwinter.