Prehistoric research

Two weeks ago on the same day, a Tuesday, I had a unique opportunity to help with some research in the prehistoric flint mines in Rijckholt, Maastricht. Two researchers from the University of Vienna were present for a full day in the mines in Rijckholt. These mines are 6000 years old. Normally you only see pictures of me from quarries were the main raw material was limestone, also called marl by the locals but the flint got thrown away. In the prehistoric time, they had flint as main as material and the marl got thrown somewhere else.

The goal of the researchers from Vienna is to try and create a sort of DNA for flint. They want to be able to tell where a certain artifact comes from and that’s why those researchers are traveling the globe to take samples of the flint where necessary.


We started the day where we usually start our guided tours, in the parking lot. We started the day with a walk to the mines.

Once at the entrance of the mine, we got an introduction of what to expect and do.

Before lunch, I helped with checking the map for correctness. After lunch, I focused on documenting the day and the mines themselves.


Lunch was provided and delicious after already half of a day of hard work.

We also got further explanation of the research and why we were doing what we were doing.

There were three groups, each of the groups had their own research topic and responsibilities. I was part of the group that was going to get into the mines, document the mine with photos and check the map for correctness. The mines itself are not always open, while the main corridor is, so this was a unique opportunity to crawl into those little galleries and corridors.

The main corridor

It was hard working, photographing in such a small space but it was worth it. It’s part of the experience and very useful for the future guided tours.

There is some more press information sadly only in Dutch:

If you want to know more about it, come and check the guided tours we organize on Wednesday evenings. You can book over here:

Myotis Myotis

Myotis Myotis

Let’s just call it Myotis in this article to keep it clear and easy.

A couple of weeks ago, we were walking in a quarry and since we were halfway the autumn that moment, bats were actively settling and searching for spots to get ready for hibernation. The quarry was very low, I don’t know the exact numbers but some hallways were only 2 meters high. There were already a lot of bats hanging from the ceiling, which is low and perfect for observing those cute little fluffy balls. There was one I fell I was fascinated by. He was in the perfect spot. The first thing that we noticed was that he was big, like the size of a regular hand. For a bat here in the surroundings, that’s pretty big. I took some time to take pictures. Once at home, I wanted to know what species it is. I am not an expert myself so I asked around and some time ago I got the chance to ask John Hageman, who knows a lot about them, what species it could be and as I already guessed or suspected, this bat was a rare one, the M.Myotis aka the (EN) Greater Mouse-eared Bat; (FR) Grand Murin; (DE) Mausohr; (ES) Murciélago Ratonero Grande; I am very pleased with the result because when I started cakewalking, I heard that this was the bat to find and it’s a rare one. I decided to collect some information about the bat and put it in a blog post, just for people as interested in me.

The Myotis is one of the largest bats in Europe. The wingspan starts from 35 centimeters and can go up to 43 centimeters. It weight can be between 28 and 40 grams. It weighs the most (just a couple of grams more than during the rest of the year) just before it goes into hibernation and can loose up to the almost the half of its normal body weight during hibernation. This bat is a low-flyer, it hunts on insects on the ground like beetles, spiders, and crickets. They hunt them by listening to the sounds the insects make and not on echolocation itself. it’s the biggest bat of Western-Europe.

The species is listed on the ICUN list as ‘Least concern’ since 2008, before that, they were near threatened so they are recovering from hard times. According to Natuurpunt, they weren’t spotted at all in the summer periods of 1987 till 2002. They are spotted at least once a year these days so they are still rare. These bats become active the first half-hour after the sun goes down and they stay away all night.

Hopefully, we will be able to spot more of this species in the future, they are pretty spectacular.

Used sources:

Underground Landscapes

It’s underground season so you can expect more underground landscapes or throwbacks to the autumn trips I still haven’t processed. The pictures in this post are from an underground quarry we explored recently.

In 1922 the local authority got the permit to start the quarrying and in 1976 an organisation got a permit to use the quarry for mushroom-growing so this means that it is a pretty young quarry and it also looks like that.

This quarry is perfect for bats, they hang on the ceiling everywhere so walking through this quarry has to be done with caution since they sometimes hang a couple of decimetres above your head. I found one very big one, but I don’t know what kind it is.