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Olm (Proteus Anguinus)Olm (Proteus anguinus) - closeup of the head.The head of the black Olm subspecies (Proteus anguinus parkelj)Olm (Proteus anguinus) - closeup of the head.Olm (Proteus anguinus) in its natural habitat.
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Olm Facts

Five groups that classify all living things
A group of animals within the animal kingdom
A group of animals within a pylum
A group of animals within a class
A group of animals within an order
A group of animals within a family
Scientific Name:
The name of the animal in science
Proteus Anguinus
The animal group that the species belongs to
What kind of foods the animal eats
Size (L):
How long (L) or tall (H) the animal is
2.5cm - 30cm (0.9in - 12in)
The measurement of how heavy the animal is
2g - 150g (0.07oz - 5.3oz)
Top Speed:
The fastest recorded speed of the animal
8km/h (5mph)
How long the animal lives for
10 - 50 years
Whether the animal is solitary or sociable
Conservation Status:
The likelihood of the animal becoming extinct
The colour of the animal's coat or markings
Pink, White, Peach
Skin Type:
The protective layer of the animal
Favourite Food:
The preferred food of this animal
The specific area where the animal lives
Underground watery caves
Average Clutch Size:
The average number of eggs laid at once
Main Prey:
The food that the animal gains energy from
Insects, Worms, Snails
Other animals that hunt and eat the animal
Fish, Toads, Birds
Distinctive Features:
Characteristics unique to this animal
Elongated body and undeveloped limbs

Olm Location

Map of Olm Locations
Map of Europe


The olm (also known as the proteus or the cave salamander) is a blind amphibian exclusively found in the underwater caves of southern European lakes and rivers. The olm is also known as the human fish, which refers to the colour of its skin.

The olm is the only species in its genus and is found inhabiting the waters that flow underground through an extensive limestone region including waters of the Isonzo river basin near Trieste in Italy, through to southern Slovenia, south-western Croatia, and Herzegovina.

The olm is most well known for living its entire life in the darkness of the underwater caves, which has led this species to adapt quite strangely to life without light. The most notable feature of the olm is the fact that it is blind as its eyes are not properly developed and instead it must rely on incredible hearing and smell to understand it's surroundings.

In a similar way to the axolotl, the olm does not undergo the drastic transformation from young to adult in the same way that frogs and toads do. The olm is also entirely aquatic, hunting, mating, eating and sleeping in the darkness of the underwater caves.

As with other amphibious animals, the olm is a carnivore meaning that it gets all the nutrition it needs from eating other animals. Small invertebrates are the main source of food for the olm including worms, aquatic insects, larvae and snails.

Due to the fact that the olm lives out its life in the safety of a dark, underwater cave, it has fewer predators than it would have living both in the water and on land. Fish and other amphibians are the primary predators of the olm along with the very occasional rodent or bird.

The olm does not reach sexual maturity until it is between 10 and 15 years old, and after mating, female olms lay from 5 to 30 eggs in between rocks in the water where she can protect them from hungry predators. Olm tadpoles are less than an inch long when they hatch and take on the appearance of the adult olm by the time they are a few months old.

Today, due to rising levels of water pollution, olm populations are declining meaning that the olm is now considered to be vulnerable to extinction in their native environment.

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First Published: 14th June 2010, Last Updated: 24th January 2020

1. David Burnie, Dorling Kindersley (2008) Illustrated Encyclopedia Of Animals [Accessed at: 14 Jun 2010]
2. David Burnie, Kingfisher (2011) The Kingfisher Animal Encyclopedia [Accessed at: 01 Jan 2011]
3. Dorling Kindersley (2006) Dorling Kindersley Encyclopedia Of Animals [Accessed at: 14 Jun 2010]
4. Richard Mackay, University of California Press (2009) The Atlas Of Endangered Species [Accessed at: 14 Jun 2010]
5. Tom Jackson, Lorenz Books (2007) The World Encyclopedia Of Animals [Accessed at: 14 Jun 2010]