When the water that created Cueva de las Estegamitas disappeared from its interior, due to the drop in sea level, air replaced water inside the cave. An atmosphere different from the outside was formed in the cave, with different characteristics.
The presence of underground air allowed (and allows) the observation of extraordinary morphological characteristics: its walls and ceilings are formed by a combination of undulating and soft surfaces, indicative of its hypogenic origin. A delicate geometry where large rooms alternate with galleries and narrow passages where barely one person can fit. Ancient water levels have left marks on the walls, allowing us to imagine a long and complex geological evolution.
The 1,303 linear meters explored and mapped of its speleological layout contain a total volume close to 10,000 cubic meters. Its environmental parameters are surprising, with an average temperature of 21°C (the highest one of the caves in Malaga), a relative humidity of 91%, a CO2 concentration of 810 parts per million (almost double the outside atmospheric concentration) and an average activity of Radon, a typical gas of the underground world, of 1308 Bq/m3.
These parameters, representative of the current underground atmosphere of the cave, are logically influenced by the recent opening of the artificial opening of the cave, due to the mining activity of the quarry in the cement factory in the neighbourhood of La Araña (Málaga), and that allowed its discovery in the spring of 2021. Until that moment, the cave had remained isolated from the outside, which has been essential for its excellent state of conservation, along with its exceptional geological content. However, there is some evidence that allows us to suspect that at some point there may have been a practicable entrance for the fauna and, perhaps, also for the prehistoric human beings who populated the Malaga Bay for tens of thousands of years. This evidence is shown in the multiple sites located in nearby caves, such as the Hoyo de la Mina, now unfortunately destroyed, the Navarro IV cave, with extraordinary Palaeolithic cave paintings, both located a few meters from Cueva de las Estegamitas, and declared a Site of Cultural Interest, the Raja del Humo, or the nearby Cueva de la Victoria and Cueva del Tesoro, in the neighbouring municipality of Rincón de la Victoria.