Black Olm

*For the white olm, click here*

## About

A black olm.

The black olm ***(Proteus anguinus parkelj)*** is a highly enigmatic cave salamander endemic to Slovenia and is the only recognised subspecies of the more well-known white olm ***(Proteus anguinus)***. The subspecies was first discovered in 1986 and described in 1994 by researchers of the Slovenian Karst Research Institute in the Diblicica karst spring. The black olm has a serpentine body with short limbs and smooth skin with a dark pinkish-brown, dark maroon or black pigment, mirroring the lighter tan or pink of the white olm. They have long heads with pronounced blunt snouts and dull, almost vestigial eyes which have very poor sight. Olms have three feathery branch-like gills on either side of the back of their head, which serve respiratory purposes. Like white olms, the black olm's body is covered in over a dozen lateral grooves on either flank. The skin on the ventral side of the black olm is translucent and leaves organs slightly visible. The black olm is slightly longer than the white olm, having 34-35 vertebrae as opposed to the white olm's 29-32.

## Diet

The black olm preys upon small invertebrates like insects, their larvae and other such species. It is likely that the subspecies uses similar chemo and mechanoreception methods to hunt and discern its location as the white olm though, likely depends more on electroreception as other senses are notably weaker. It uses electroreception via the use of tiny electroreceptors along its face and snout. The functioning eyes of the black olm also allows the subspecies to hunt with better visibility though, the eyes are still weak in comparison to other amphibians. Black olms have a shorter and stronger jaw in comparison to white olms and their jaw muscles are much more pronounced, being visible through the skin on the head via two bulbous structures.

## Conservation Status

The black olm has not been evaluated by the IUCN, though it has been described "highly endangered" and "extremely rare" by the Tular Cave Laboratory, which studies both black and white olms. Reasoning given for this assumption is that the species inhabits only a small local area and that a small local pollution incident could cause massive detriment to the subspecies. It is said that the black olm is mostly threatened by waste like agricultural, municipal, industrial and sewerage runoff, which pollute valuable habitat. It is likely that concentration of chemicals in the environment can be detrimental to black olms, with nitrates being particularly dangerous.

## Range and Population

The black olm occurs locally near the small town of Črnomelj, Slovenia in an area of cave below 100km² (39mi²). It lives in what is known as a karst landscape, a biome identified by cave systems, subterranean networks and sinkholes, specifically inhabiting less than 10 karst springs behind Bela Krajina, a karst area of less than 30km² (11.6mi²) in southeast Slovenia. It is likely that the black olm comes to the surface during flooding events, as locals had reported seeing the subspecies before its identification during floods. The population of the black olm is unknown, though likely small.

## Behaviour

Little is currently known about the behavioural characteristics of the black olm, as the species is highly enigmatic and seldom-documented.

### Relationship with Humans

The black olm is incredibly valued among the Slovenian public as a highly threatened and infamous animal. In February, 2019, the Zupančič tourist farm, in cooperation with the municipality of Črnomelj, the Development and Education Center Bela krajina, the Proteus association and the Novo Mesto unit of the Institute for Nature Protection at the spring of Jelševniščica in Jelševnik near Črnomlje, has already began to implement a series of infrastructure interventions to allow the public to view the animal in the in captivity via the Zupančič homestead, a thermally controlled exhibit which aims to display the subspecies in a replica of its natural habitat. The initial project ended govenrment support in Novemeber, though the Zupančič family still maintains the exhibition currently. This project will hopefully have a similar effect on ecotourism in the nation as white olm tourism has, raising awareness for the subspecies. The mayor of Črnomlje, Andrej Kavšek, has shown particular interest in the preservation of the black olm, not only helping initiate the tourism project, but also urging awareness about the subspecies and its rarity across Slovenia.

## In Captivity

The Tular Cave Laboratory in Slovenia has housed seven individual black olms since 2002. These individuals are monitored and maintained with care and the Laboratory hopes to use them for study on the subspecies, as to understand more about them as a whole. In the Zupančič homestead, the genetics of the black olm are to be studied to determine whether disease in the subspecies is apparent or preventable.

## Sources

* The Black Olm | ČRNA ČLOVEŠKA RIBICA - https://crni-moceril.si/en/the-black-olm
* Olm | Wikipedia - https://en.wikipedia.org/wiki/Olm#Black\_olm
* Black Proteus | Tular Cave Laboratory - https://www.tular.si/index.php/proteus/12-black-proteus
* From now on, the black human fish can also be viewed by "ordinary" visitors | DVEVNIK - https://www.dnevnik.si/1042875693
* Black human fish - the mysterious world of the Belokraj underground | Lipov List - https://lipovlist.turisticna-zveza.si/crna-cloveska-ribica-skrivnostni-svet-belokranjskega-podzemlja/
* From now on you will also be able to watch the rare black human fish | SiolNET - https://siol.net/novice/slovenija/odslej-si-boste-lahko-ogledali-tudi-redko-crno-clovesko-ribico-video-491467