Newborns live mainly in Southern Europe – Photo: GETTY IMAGES

To date, lizards are considered the only vertebrates in Europe that live entirely in caves. Their bodies have evolved to adapt to life in complete darkness with degenerated eyes while their sense of smell and hearing are highly developed.

In addition, unlike all other amphibians – which live both on land and in water such as frogs, frogs, and lizards – they spend almost their entire lives in the water environment.

According to Dr. Gergely Balázs of Eötvös Loránd University (Budapest, Hungary), although it is a special species, the lizard has not been thoroughly studied, especially outside the laboratory.

New Scientist site noted that since 2010, Dr. Balázs’s research team has been pursuing a feat on salamanders.

On the population in Vruljak 1 cave, eastern Herzegovina (Southern Europe), the team marked in batches a total of about 40 individual lizards and recorded their travel distances in different periods.

In an experiment, the team recorded the largest distance that the salamanders moved in 230 days was only 38m, in addition, no animal went more than 50m from the cave entrance.

During the 100 days between two measurements, Dr. Balázs said, most thunderstorms moved only 10 meters. Only 10 thunderstorms can go more than 10m and only 3 can go more than 20m.

In particular, there are individuals who only stay in one place for 2,569 days, equivalent to more than 7 years.

Living in a dark environment, the eyes of lizards degenerate – Photo: FLICKR

The research team explains: due to the characteristics of living in deep caves and surrounding darkness, the lizard has few enemies to face, so it does not need to move much to escape. In addition, their food is mainly plankton so they can “use stillness to control movement” to catch prey.

This makes the lizard one of the “laziest” animals on Earth today compared to its size (20-30cm long). In the experiment at Eötvös Loránd University, the research team used 20cm long salamanders.

“They just hang around one area and hardly go anywhere or do anything else” – Dr. Balázs said.

Research will help scientists add evidence about the evolutionary process of animals like what Charles Darwin (1809 – 1882) wrote. Previously, animals living in dark places were always Darwin’s primary concern while researching the origin of species.