Martin's Cave sits more than 700 feet up the eastern cliffs of the Rock, behind a padlocked gate. In the 1960s it held roughly 5,000 Schreibers' bats and 1,000 greater mouse eared bats. A survey in 2002 found no bats in it at all. That single cave is the whole story of bats in Gibraltar in miniature. The popular version of this subject imagines thriving colonies hidden inside 55 km of military tunnels, waiting to be discovered. The real position, according to the [Gibraltar National Museum's own Gib-Bats project](https://www.gibmuseum.gi/our-work/gib-bats), is that more than 98% of Gibraltar's bats have disappeared since the 1960s. Five species are locally extinct. There is no secret colony. There is a small, closely watched remnant, and a project trying to work out what is left. The first bat counts in Gibraltar date from the 1960s and 1970s and came to more than 36,000 animals, overwhelmingly two cave dwelling species: Schreibers' bat and the greater mouse eared bat. The museum is honest that those counts were not scientific and were made by people who were not specialists. They are still the only baseline anyone has. Set that 36,000 against the present. The species lost locally since then are the greater mouse eared bat, the brown long eared bat, the barbastelle, and two horseshoe bats, the lesser and the Mediterranean. Those are not species that became scarce. They stopped being recorded here. > A 98% loss is not a decline. It is a collapse that happened while almost nobody was counting. Gibraltar looks purpose built for bats. There are thought to be [more than 200 caves](https://en.wikipedia.org/wiki/List_of_caves_in_Gibraltar) in a territory of 6.7 square kilometres, and [about 34 miles, or 55 km, of tunnels](https://naturereserve.gi/our-rock/wwii-tunnels/) driven through the limestone between 1782 and 1968. The Second World War phase alone took the network from about 11 km to 40 km. That is nearly twice the length of Gibraltar's entire road network, all of it dark, and much of it at a steady temperature year round. The habitat is there. The bats are not. The museum's summary is that protected roosts abandoned decades ago are now showing early signs of reuse by species that had gone, but in low numbers. Those roosts are monitored rather than promoted, which is the correct decision and also the reason you will not find a tunnel on any tour that is sold as a bat cave. Gib-Bats started in 2013, when a team of UK bat specialists led by James Shipman approached the Gibraltar National Museum, the Department of the Environment and the [Gibraltar Ornithological and Natural History Society](https://www.gonhs.org/). GONHS has held the brief for bats through its Mammal Section since it was founded in 1976. By 2016 the project had taken Gibraltar's official species list from three to eight and trained three local workers to full bat licences. |Species|What it is|Status in Gibraltar| |Soprano pipistrelle|One of Europe's smallest bats|On the official list| |Kuhl's pipistrelle|The common Mediterranean pipistrelle|On the official list| |Schreibers' bat|Cave specialist, IUCN Near Threatened|Present, once the dominant cave species here| |Isabelline serotine|Iberian and North African serotine|New to the list on the project's first visit| |Greater horseshoe bat|Horseshoe bat of caves and roof spaces|Rare, first confirmed in August 2016| |European free-tailed bat|Big, fast, calls low enough to hear unaided|On the official list| |Greater noctule|Europe's largest bat, 41 to 46 cm wingspan|Seasonal visitor| The eighth species is where honesty beats guessing. The museum states the list stands at eight, but its public summary names seven. We could not find the eighth named in any source we could verify, so we are not going to invent it. If you need the complete current list, the Gibraltar National Museum and GONHS are the two bodies that hold it. One point of detail that gets mangled elsewhere. The horseshoe bats recorded as locally extinct are the lesser horseshoe and the Mediterranean horseshoe. The bat found in August 2016 was a greater horseshoe, a different species, and a first for Gibraltar. Dr Geraldine Finlayson found it deep inside the Rock, and it was identified by Stewart Finlayson and Giovanni Santini with Dr Rhian Guillem of GONHS and trainee Kelsey Rowbottom. It was [a juvenile female, born that year](https://www.chronicle.gi/new-mammal-spotted-on-the-rock/), almost certainly dispersing in search of feeding grounds. One young animal, not a colony. Most bat watching needs a detector, because pipistrelles call somewhere around 45 to 55 kHz and you will never hear them. The European free-tailed bat is the exception, and it is the single most useful fact on this page. It hunts in open air above rooftops and its calls peak [somewhere between 12 and 17 kHz, typically near 13 kHz](https://www.batmonitoring.org/en/species/tadarida-teniotis/), and as low as 11.4 kHz in one Swiss study. Sources vary on the exact figure, wh