Animals

Did You Know? Incredible Olm Facts

Olm facts are interesting for kids.
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Are you ready to learn about one of the most interesting species dwelling in underwater caves? The olm or Proteus aguinus is as old as its name sounds. They can be defined as the cave salamander that lives completely submerged in water. They dwell in European caves with limestone formations, especially in countries like Croatia, Herzegovina, Italy, and other places of the Dinaric Alps. In Croatia, they are revered as an important mythological species. There is no distinct olm meaning; however, it may have come from the German word 'molch' meaning salamander. The olm has an eel-like look with blind eyes on their head and extremely pale skin that may look like human skin. However, the species is known for their superior sensory receptors that help them to swell in the submerged caves. People have also thought of them to be baby dragons. Currently, enlisted as Vulnerable, the olm population is at threat due to water pollution. Only proper conservation can save them. So, keep reading to know more about the great olm.

Want more fun facts about animals? Check out our articles on water dragon facts and African bullfrog facts.

Olm

Fact File

What do they prey on?

Shrimps, snails, insects

What do they eat?

Carnivore

Average litter size?

35-70 eggs

How much do they weigh?

0.1-5.3 oz (3-150 g)

How long are they?

8–12 in (20-30 cm), some can grow up to 16 in or 40 cm

How tall are they?

N/A

What do they look like?

White, sometimes black subspecies are also found

Skin Type

Pale skin

What are their main threats?

Sunlight, water pollution

What is their conservation status?

Vulnerable

Where you'll find them

Karst formations found in the caves of the Dinaric Alps

Locations

Southern and Southeastern Europe

Kingdom

Animalia

Class

Amphibia

Scientific Name

Proteus anguinus

Family

Proteidae

Genus

Proteus

Olm Interesting Facts

What type of animal is an olm?

An olm (Proteus anguinus) is a form of cave-dwelling aquatic salamanders.

What class of animal does an olm belong to?

An olm (Proteus anguinus) falls under the class Amphibia and within the family Proteidae.

How many olms are there in the world?

The exact remaining numbers for this subterranean cave-dwelling salamander are hard to find. However, several factors like water pollution have reduced the number of olms in the wild.

Where does an olm live?

An olm (Proteus anguinus) is found in the subterranean caves of the Dinaric Alps. The caves have a karst topography mainly constituting limestone bedrocks. As a cave salamander, an olm is found in Southern and Southeastern Europe. An extensive population of olms lives in the Soča River basin of Italy as well as in the Southern part of Slovenia, and Croatia. They are the only member of the Proteidae family that inhabit Europe.

What is an olm's habitat?

The olm is the only amphibian that completely lives underwater, dwelling in the crevices of underground limestone bedrocks. An olm prefers to live in well-oxygenated waters, with a temperature of around 46-52 °F (8-11 °C). Olms are almost blind, but they are quite sensitive to other sensory approaches with a mix of sensitive chemo-, mechano-, and electroreceptors. In the depths of a cave, the olm finds its path through its keen sense of smell because it is able to detect even the smallest of organic compounds. There is a sub-species of olms known as the black olm or Proteus anguinus parkelj, which is known to get to the surface of the cave.

Who do olms live with?

Olms are defined as gregarious animals who like to live with each other in the fissures and cracks of rocks. However, a male olm can become territorial when they are sexually active. Olms have a defined and unique mating ritual where the males battle it out even before the females are ready to mate. Once a male olm has won over others, he produces a scent to attract the female. The female olms define special territories to lay eggs and to look over the tadpoles.

How long does an olm live?

The average age of an olm is said to be 58 years. However, some studies show that this blind cave-dwelling amphibian can even live to be 100 years old. Many reasons have been stated, one being that the long life is due to an absence of predators for the olms who can enjoy their underground lives with ease. Olms can also live a long time without food. Some scientific studies even found that they can survive for 10 years after eating a single shrimp.

How do they reproduce?

A female olm mate with a male olm to produce 35-70 eggs in a single clutch. There is an elaborate mating ritual followed by the males to attract the female olms. The eggs are fertilized through spermatophores. The olms are known for their long courtship rituals, which can last for hours. The optimum temperature for the embryos to develop inside the eggs is 50 °F or 10 °C, and it can take approximately 140 days. The time taken to hatch depends on the temperature of the waters. It can take only 86 days if the water is warm. The species takes about 14 years to reach sexual maturity, and they mate in intervals of 12 years. The tadpoles of an olm are very small, with a length of just 2 cm or 0.8 in.

What is their conservation status?

The olm is currently Vulnerable according to the International Union for Conservation of Nature (IUCN) Red List. Even though the olms do not have a natural predator, their main threat is water pollution. People have seen olms being washed up due to heavy rains, which helped in their first identifications. These European olm salamanders are also losing their lives due to the introduction of pesticides, fertilizers, heavy metals, and microplastics in their underground cave environments. Slovenia is one of the countries where the species are extremely threatened, and the country has worked towards conservation after Slovenia joined European Union. The species is regarded as critically endangered in Croatia to protect them from poaching. Herzegovina and other European countries are yet to shed light on their conservation status of the olm salamander.

Olm Fun Facts

What do olms look like?

The olm species have been long known as the 'human fish' because of their human-like pale skin. An olm doesn't belong to the fish species; instead, they are an amphibian. The olm's head is shaped like a pear, and it holds their underdeveloped eyes. The eyes can also be covered with their skin. There is a sub-species called the black olm (Proteus anguinus parkelj) that have pigmented skin along with more developed eyes. Due to their underground habitat, the skin of the species is extremely pale, and you may even get a look at their organs. The species has a bit of riboflavin in their skin that produces enough pigment to make them look pink or yellow. The olms have a long eel-like body with small underdeveloped limbs that help them to move around. The species have a laterally flattened tail, and it is surrounded by a very thin fin. In the back of its head, you can see the frilly gills. However, the aquatic species also have lungs for breathing. The mouth is flat and small, but it has several small teeth that have the role of a sieve to restrict bigger particles while it is eating.

Olm facts help to know more about amphibians.

How cute are they?

Olms are an extremely cute species and their almost blind look gives the appearance that they are floating in the waters.

How do they communicate?

A lot isn't known about their way of communication. These aquatic cave species have their unique way of getting around the water. They have a mix of sensitive chemo-, mechano-, photo-, and electroreceptors that help them to get around the caves.

How big is an olm?

The average length of an olm is 8–12 in (20-30 cm). They are the longest amphibians in their native habitat. Olms are a tad bigger compared to the spotted salamander that grows 5.9–9.8 in (15-25 cm).

How fast can an olm move?

Though extensive scientific studies haven't been done, an olm can travel at an average speed of 5 mph or 8 kmph.

How much does an olm weigh?

As small, slim animals, the olm does not weigh a lot. The average weight of an olm is around 0.1-5.3 oz (3-150 g).

What are their male and female names of the species?

There are no distinct names for a male or a female in the olm species.

What would you call a baby olm?

A baby olm might be called a tadpole.

What do they eat?

The species mostly depends on shrimps, snails, insects, and other crustaceans.

Are they poisonous?

No, olms aren't poisonous in nature.

Would they make a good pet?

No. Olms are vulnerable animals that like to hide in between the rocks of a cave. Besides being illegal to keep, an olm pet will not survive in a habitat that fails to match its own aquatic lifestyle.

Did you know...

Search olm with the local name of 'Čovječja ribica' in Croatia and Herzegovina. It stands for 'human fish'.

How often does an olm eat?

Usually, the olm species do eat regularly, but they have the ability to stay alive without eating for a long time. Some have even survived without eating for 10 years. In times of starvation, they can also reduce their metabolic rate.

Development of the olm

Olms do not reach adulthood like other amphibians because they do not have metamorphosis or adaptations like them. Instead, the tadpoles grow in body size to become a full-grown olm and even reach sexual maturity in such a body. It takes just four months for an olm to grow in size to have a complete body. There was a time when they were thought to be baby dragons. However, they aren't baby dragons or axolotls, a similar animal that hails from Mexico, but their own unique selves.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other amphibians including spotted salamander, or tiger salamander.

You can even occupy yourself at home by drawing one on ourolm coloring pages.

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