Biology in popular culture – movies&TV (part 2)

Hello everyone and welcome to another post in the series about biological topics in movies and TV series. You can find a link to the previous post right here. My intention with these is to clarify different claims made in various movies and TV shows I watched, and also to share perhaps some surprising facts mentioned in them. If you’d like for me to watch something specific, please let me know (I’m currently preparing another post focused on the German TV show “Biohackers”). So let’s start with some extremely popular offenders.

Friends – “Lobsters mate for life”
In a classical Friends episode, Phoebe claims that lobsters mate for life. They don’t. There are some animals that remain monogamous for life, such as wolves, swans, penguins, and barn owls, but lobsters are not one of them; in fact, male lobsters actually change mates frequently during the mating season.

Harry Potter and the Goblet of Fire
During the famous scene in which professor Moody tortures the amblypygi (of species Damon diadema; Amblypygi belong to class Arachnida) with the Cruciatus curse, poor creature starts to squeal in pain, but can amblypyg actually make that sort of sounds?
As it turns out, some species of spiders (which also belong to class Arachnida ) can tap on the surface or even vibrate (again, on certain surfaces) to make mating calls or communicate, but the type of screech depicted in the movie, under the spell or not, is physiologically impossible.

This beautiful Damon diadema belongs to my good friend Iva; for more photos like this one, you can follow her on Instagram

The Alienist – “Butterflies inflict pain during the coitus”
While I’m still on the topic of invertebrates, let’s divulge into this one. Now, pain is the subject of many definitions, but assuming it’s just an unpleasant physical stimulus, the question is raised whether insects can actually feel it? Until recently, researchers agreed that insects can feel nociception, which is the response to life-threatening stimuli, but most agreed that they don’t feel the pain like we do. A recent study, however, showed that fruit-flies could experience a chronic pain-like state, but the science still has a long way to go to conclusively show if insects can or cannot feel pain. Do butterflies feel pain when mating? Possible, but it seems that, until more evidence comes to light, it’s highly unlikely.

Rouge – “Lions are not afraid of fire”
This fun but quite forgettable B flick starring Megan Fox and a CGI lioness off-handedly mentioned that lions are, in fact, not afraid of fire. That didn’t sound right with me so I searched for it and it seems like it’s true. Apparently, not only they’re not afraid but like to check out what’s happening around the campfire. I would like to point out, however, that most of the web-sites are literally copying the same sentence about it, verbatim, and I didn’t find where it originated.


Did you notice similar misinformation or surprisingly correct information in popular movies and TV shows? Please let me know in the comments below, I love reading about movie mistakes!

Literature & more information:

11 Animals That Mate For Life

The Weird World of Lobster Sex

Spider’s Creepy Mating ‘Purr’ Recorded by Researchers

How spiders create the sounds of love

Pain in invertebrates

Do Invertebrates Feel Pain?

Insects feel persistent pain after injury, evidence suggests

Nerve injury drives a heightened state of vigilance and neuropathic sensitization in Drosophila

Is it pain if it does not hurt? On the unlikelihood of insect pain

How to Survive a Lion Attack

Short science posts | Eluding Ctenophora

Ctenophora, commonly known as comb jellies, are a rather perplexing phylum of beautiful pelagic creatures. Their evolutionary position has been debated for many years as is the origin of their nervous system (some scientists believe they are older than sponges and that sponges lost their nervous system, while others advocate the theory about the nervous system forming independently twice, once in cnidarians and once in ctenophores).
Ctenophora have two nerve nets: subepidermal and less organized subgastrodermal, which recent research identifies as a mesogleal nerve net. Nerve cells from this layer communicate with muscles by synapses and affect the locomotion of the body. The subepidermal net is denser around the mouth, the pharynx, and under the comb rows (comb rows are strips that run the length of the ctenophore body and contain cilia called “ctenes”). Ctenophore neurons can be iso- and multipolar.

They have sensory cells on the whole surface of the body and those correspond to vibrations and thermal and chemical stimuli: more receptors are located around the mouth and pharynx. Ctenophora also have an apical and aboral sensory organ. Such sensory organ consists of a statocyst, a sensor that contains a statolith that balances on four groups of long cilia connected to the comb rows. These organs help the orientation of the ctenophore body.
What’s extremely interesting is that ctenophores use different chemical signalling system than the ones described in the previous posts, mainly because these animals simply lack the neurotransmitters (and genes), such as serotonin, dopamine, noradrenaline, and acetylcholine; glutamate is the only neurotransmitter currently known to be present.

I gathered all this information from different resources, and some are sometimes contradictory or are generalizing conclusions about the whole phylum from the data of only one ctenophora species. This is the best overview I could manage, to show both the similarities and the differences of the ctenophora nervous system, when compared to the Cnidarian system. These lovely animals are not very well researched and I’m sure many wonderful breakthroughs about their anatomy, physiology, and their place in the evolutionary tree are to come.

Literature & more information:
Habdija et al: Protista-Protozoa, Metazoa-Invertebrata, Alfa, 2011, Zagreb
Norekian & Moroz Neural system and receptor diversity in the ctenophore Beroe abyssicola J Comp Neurol. 2019;1–23.
Ctenophores – quick guide
Did the ctenophore nervous system evolve independently?
Aliens in our midst

Field | Crayfish alert at Žumberak Mountains

Hi everyone, and welcome back to my blog. I took a month+ long break, during which I focused on my health and final exams at my University. At the same time, BIUS – Biology Students Association was preparing for their annual field trip, that I really wanted to be a part of!
BIUS is an association that gathers many Biology students from our department and focuses mainly on field trips, excursions, and expert lectures, all in order to complement and expand our Biology-related knowledge about certain topics. BIUS is also a publisher behind In Vivo Magazine, for which I serve as editor-in-chief.

Firstly, however, I would like to write a bit about my love for scientific (and a little less scientific) field trips. My primary love is the lab, after all. However, I grew up in a tiny village, surrounded by a living world – woods, animals, endless fields of tall grass… I actually started to think about studying something science based, perhaps Biology even, way back in the primary school, after wanting to identify all the bugs and spiders I would find in my front yard.
During my first two years of Bachelor’s degree, the thought of going out to the field didn’t really cross my mind, but it all changed in the middle of my third year, when I realized that something was lacking in my life, and that something turned out to be raw nature.

Photo by Đina Nola

This year’s big field excursion lasted for eight days, but I was only able to attend for the last four. Usually, BIUS organizes this kind of excursions twice a year, in May and September, but due to the pandemic, it was completely moved to the end of September, when situation in Croatia improved. Every year, a new terrain is explored, usually switching between continental and marine area. For this year, the leadership chose the Žumberak Mountains which are located on a border with Slovenia, and are approximately one hour drive from Zagreb. Žumberak is a mountain range divided into two parts, the Samobor Hills and the Žumberak Hills, both comprising the protected nature park Žumberak – Samobor Hills. It is home to many plant, fungal, and animal species, some of which are endangered or sensitive.

At first, shortly after arriving I was planning to spend every day with a different group, but in the end, I spent all the days driving around with the Crustacean group. I wasn’t sure how much fun is that going to be, since I knew very little about freshwater crayfish, apart from researching crayfish plague for a little while as an undergrad during an elective lab course.
I was already familiar with two members, Lena and Ljudevit Luka, since we are the same generation and took multiple classes together, and I also knew Anita and Karla a little bit; the whole group was very determined to carry out their research but with the sprinkle of carefreeness. I didn’t feel excluded for one bit and they were extremely patient with me taking photographs and filming videos.

So, what did Crustacean group actually do? Anita kindly explained their goals:

  • monitoring of the species Austropotamobius torrentium, also known as stone crayfish (how many specimens, in which streams are they located, what gender…)
  • taking swabs of crayfish cuticles in order to check for crayfish plague pathogen; this is later investigated by using the PCR method
  • taking water samples using special filters in order to check for crayfish presence; this is later investigated by analyzing the eDNA (environmental DNA)

How does that actually look like out in the field?
The first thing we did every morning, was to check the map and the roads; sometimes, we drove for more than one hour to reach a destination. Then we walked up to a stream, which sometimes proved to be rather tricky, since some seemed to dry up overnight. The most important thing we did before and after walking in every stream, creek or puddle was to disinfect our rubber boots, in order not to accidentally transfer pathogens to different habitats.

The group was very active even before my arrival, so we checked some permanent streams where they already set up special crayfish traps, that were actually made of old plastic bottles, with some tasty hot dog sausages in them. (Don’t worry, those traps are reusable! They just have to be washed thoroughly.) After taking out crayfish, one by one, they are measured and gently rubbed with a toothbrush, in a special buffer, to collect possible crayfish plague pathogen. Every tube containing that buffer is then labeled and safely stored. Crayfish are carefully released back into the stream, at the same place where they were found.

However, sometimes we went to streams for the first time, which meant no traps. So how do you catch a crayfish then? With hands. Usually they were hiding under rocks, but what most people probably wouldn’t expect, is that they are freakishly fast. Still, even during night-time catching & release, every member of the group was highly skilled in catching them. They could also easily discern female from male specimens, and Ljudevit Luka readily explained how, and also sent additional images (the ones below). In short, the main difference is that male crayfish have gonopods, while females don’t. (Gonopods are modified legs that are substantial during mating.)

A female stone crayfish

In four days that I spent with this wonderful group, I learned a lot and had a really amazing time. I wanted this post to focus mostly on crayfish, but I’m planning to post another one, where I will write a little bit more about travelling, our camping site, and wonderful nature I was able to document. I also took many videos, which I’m currently editing in one coherent, presentable, work, which I initially planned to release at the same time as this article, but life got a little bit in the way.
I sincerely hope you liked this write-up, and will read my next one as well!

Here you can find social media of some of the members of the Crustacean group, as well as the KarioAstacidae website, a student project led by Ljudevit Luka and Lena, which focuses on Astacidae populations in Zagreb.

Short science posts | Hydrozoa

Hydrozoa are the last cnidarian class I’m going to write about. They can exist in two distinct shapes, as hydromedusa and hydropolyp (same as Scyphozoa and Cubozoa). Despite perhaps expecting hydrozoans to be the most advanced in both nervous and sensory systems, they don’t actually have any rophalium. Furthermore, some hydromedusae don’t even have nerve nets. However, they have two nerve rings (outer and inner) on the margins of their bells which are regarded as ganglia by some scientists.

These rings consist of neural pathways which process different sensory inputs (such as light and gravity). Aglantha digitale, a hydrozoan species, has been reported to have as much as 14 distinct neural pathways. A. digitale is also distinct from the other species in the class by having two swimming “modes” – slow (which is a characteristic for all hydrozoan) and escape mode. Transmission through giant ring neurons is responsible for both modes, but the escape mode requires a stronger contraction. The slow swim mode is activated by the input from the pacemaker, which triggers slow calcium spikes. Direct mechanical nerve ring stimulation by tentacles triggers fast sodium spikes. In short, giant ring neurons are capable of generating two different kinds of action potentials.


Gap junctions are also present in (and only in) Hydrozoa, and they transfer electrical signals through the musculature. Furthermore, I would like to emphasize that despite some hydromedusae not having a nerve net, some in fact do, and so do hydropolyps. In polyps, however, some groupings of the neurons could be found around their mouth.

Literature & more information:
Habdija et al: Protista-Protozoa, Metazoa-Invertebrata, Alfa, 2011, Zagreb
Do jellyfish have central nervous systems?
Jellyfish nervous systems

Short science posts | What is a nerve net?

A nerve net is a type of nervous system that consists of many neurons but there is no brain or cephalization. Nerve nets are found in animals with radial symmetry (Cnidaria) and biradial symmetry (Ctenophora). Despite being called a net, there sometimes exist some groupings of neural cells in some Cnidaria classes, which I will write more about during the next couple of weeks.
Cnidaria are specific due to their specialized organelles, cnidocytes, which they utilize to hunt for food or use for securing itself to a surface. Some cnidocytes contain toxins that can paralyze their prey (the burning sensation you may have felt when touching a sea anemone 😉).
As a rule, Cnidaria have two diffuse nerve nets, one in the epidermal layer and a second one in the gastrodermal layer. In between these two layers is the mesoglea, a layer that functions as sort of a skeleton. The epidermal net consists of bipolar and multipolar nerve cells, while the gastrodermal net is made up of only multipolar cells.

Cerianthus membranaecus (known as cylinder anemone or coloured tube anemone)

Cnidarian nerve systems are fascinating but also quite unexplored. What is known is that nerve cells consist of two types of neurons, sensory neurons that respond to stimuli and motor neurons which ultimately trigger a response. Chemical synapses exist and provide the communication between the neurons. Hormones have also been reported in some cnidarians (steroids, neuropeptides) but it is still not known how exactly these signalling molecules work.


In the next couple of weeks, I will write a post about every cnidarian class and also ctenophores, focusing on their nervous and sensory systems. If you have any questions or would like me to focus on something, please let me know!

Literature & more information:
Habdija et al: Protista-Protozoa, Metazoa-Invertebrata, Alfa, 2011, Zagreb
Endocrine-like Signaling in Cnidarians: Current Understanding and Implications for Ecophysiology
Evolution of sensory structures in basal metazoa

Short science posts | Do sponges have a nervous system?

Sponges (phylum Porifera) are sessile multicellular organisms that live predominantly in seas and oceans. They don’t have tissues or organs, and therefore, they don’t actually have a nervous system. However, they do have bipolar and multipolar cells that resemble nerve cells, which are found in the middle, “jelly-like”, layer.
Sequencing of some sponge species showed the presence of many genes associated with neural cells, such as genes that code enzymes for neurotransmitter synthesis and synaptic transmission. It is important to note that these genes have other functions in the organism. It has also been observed that some sponge larvae can respond to outer stimuli and show various “taxis” behaviour – phototaxis (response to light), geotaxis (response to gravity), rheotaxis (response to water current). Phototaxis has been closely studied in species Amphimedon queenslandica (class Demospongiae), a sponge native to Coral Sea.

Aplysina aerophoba, also of class Demospongiae, which can be found in Adriatic Sea.

Potassium channels have been observed in that same species, as well as glutamate, GABA, and NO systems, which have been investigated in Ephydatia muelleri, another species of class Demospongiae. Electrical signalling has been noted in glass sponges (class Hexactinellida). These sponges have bodies comprised of a syncitial tissue and their skeleton is made of silicon dioxide. The scientists were able to measure the action potential (5s long, with 29s refractory period) and deduce this signal relies on potassium and calcium ions.
Some scientists even suggest that sponges used to have a nervous system, but lost it during evolution – they introduced several hypothetical scenarios for this event, proposing that sponges lost their nervous system in order to focus on filtering.

Literature & more information:
Habdija et al: Protista-Protozoa, Metazoa-Invertebrata, Alfa, 2011, Zagreb
Evidence for Glutamate, GABA and NO in Coordinating Behaviour in the Sponge, Ephydatia Muelleri (Demospongiae, Spongillidae)

The GABAergic-like System in the Marine Demosponge Chondrilla Nucula
Where is my mind? How sponges and placozoans may have lost neural cell types
Elements of a ‘nervous system’ in sponges

Short science posts | Nervous system evolution

For the next couple of weeks, I would like to write a bit about the evolution of the nervous system, from early nerve cells to the human nervous system and brain evolution. Alongside nervous I will also focus, to a lesser extent, on sensory systems. These posts will be published on my Instagram account, but I decided to publish them on the blog as well.

Mostly, these posts will be about various animals and the nerve systems they have – nerve nets, nerve cords, complete systems. The main process behind this is called cephalization, and it starts with the groupings of nerve cells and ganglia at one end of the body. After some (long) time, this process led to us having a head with sensory organs and a brain inside it.

But when did all of it start? It is kind of hard to say, for even single-celled organisms, such as bacteria, have voltage-gated channels and genes that support the theory of possible synaptic transmission. These channels are potassium (the oldest), calcium, and, rarely, sodium channels as well. Action potentials have been detected in some algae and diatoms, although their function is mostly unclear. In Chlamydomonas (unicellular green algae) on the other hand, potentials were detected in flagellums, which clearly suggest they play the part in the movement of the algae. Action potentials were also recorded in the cilia of some protists, such as Parmecium.

Of course, the exact evolutionary processes are unknown, and there is a possibility that these organisms acquired the mentioned features later than scientists now assume. It is also possible that some more evolved organisms, such as sponges, subsequently lost some of the features discussed here (more about this in the next week’s post).

Literature & more information:
Habdija et al: Protista-Protozoa, Metazoa-Invertebrata, Alfa, 2011, Zagreb
Bacterial voltage-gated sodium channels (BacNaVs) from the soil, sea, and salt lakes enlighten molecular mechanisms of electrical signaling and pharmacology in the brain and heart
Early evolution of neurons
Deep evolutionary origins of neurobiology
From damage response to action potentials: early evolution of neural and contractile modules in stem eukaryotes

Another Vienna adventure!

Hi everyone, if you follow me on Twitter and/or Instagram, you have probably already seen my pictures from Vienna this last weekend. However, I would like to share a bit more, and write about it too!

At Saturday at 3.30 in the morning, my sister & me boarded the bus in Varaždin, and started our one-day adventure. Our destination? Vienna, capital of Austria! With the trip we booked through Galileo Travel came scenic sightseeing of the city, and a visit to Schönnbrun castle, but we skipped that and with U4 headed directly to city centre, Schwedenplatz more correctly. After short breakfast in McDonald’s (I know, I know), we headed to Natural History Museum. On the way there, we took some typical tourist pictures, in front of Stephan’s Cathedral, at Hofburg… And then we finally reached NHM.

I’ve visited the museum two times before, but my enthusiasm was still through the roof. Firstly, the museum is huge. Permanent exhibition spans two floors and numerous specimens. Roughly divided, first floor is mineralogy and second floor is dedicated to zoology. I took some pictures, which I will share with you, but I didn’t take my camera; everything is taken with my Huawei mobile phone.

Student’s entrance fee is only 7€ (~8$), and taking photographs is allowed. The whole museum is, honestly, overwhelming. I have never before seen so many specimens at once place. My sister, who visited it for the first time, often commented that a building itself could be a museum, due to it’s rich, ornate walls. First floor is, like I already mentioned, full of minerals. I don’t have much interest for them, but I made me think about how old our planet is, and what makes it. Also, one of the rooms is completely dedicated to jewellery, both modern and historic.

The floor dedicated to zoology was full of models and real specimens of animals around us, as well as evolutionary artifacts. As is common, first rooms were dedicated to invertebrates, building it’s way up to vertebrate groups. I was particulary amazed by the size of dinosaur bones – no matter how many times I see it on the TV, or visit this museum, I stand in awe in front of them.

Unfortunately, due to morning sun, I wasn’t able to capture nice photographs of invertebrate collections, but trust me when I say those are so beautiful. Everything is o neat and organized that, since then, I’ve been toying with idea of collecting my own specimens. There are also rooms dedicated to fish, amphibians, reptiles, birds… Those are usually held in special containers or stuffed. There are also many skeletons on display on the walls. With dinosaurs, there were also animatronic models, which both excited and frightened children in the museum.

Latimeria chalumnae, a living fossil!

There is also a separate room dedicated to evolution of human. I already posted that interesting picture where an app transformed me into an early human, but in this part of the museum, you can see many different skulls belonging to Homo sapiens, Homo neanderthalensis, Homo habilis… I consider this part of the exhibition very important, especially in today’s time, when so much misinformation is present on the Internet.
Another important historic specimen is Venus of Willendorf figurine, which is dated to 30 000 years BC.

Venus of Willendorf


What would you like to see, if you could go to Natural History Museum in Vienna? Would you like me to write about something in more details?
Please let me know in the comments 🙂

Biology in popular culture – HEAVY METAL

Many of you might not know this, but I was (and still am) a big fan of metal music. I included word “heavy” in the title, but I actually prefer doom, melodic death, death, some black metal and also gothic/love metal. What does this have to do with biology? Well, many bands use animal imagery in their music videos or album art, with some of them being really interesting.
Of course, there are many that are obvious (Powerwolf, anyone?), and some animals are used more than others (crows, snakes). However, I wanted to see which animals dominate the heavy metal world, and which bands, that are usually not connected to such artwork, would use it.

Now, I would very much like to include these album covers in this post, but they are copyrighted and I’m not 100% sure I can do that, so if you’re not already familiar with the covers, I would kindly ask you to use a search engine, or links I’ll provide to each cover.

Paradise Lost

A doom/gothic/synth-pop band from the United Kingdom, Paradise Lost often uses biological motifs in their album art (Medusa, 2017; Tragic Illusion 25, 2013; Tragic Idol, 2012), but I would like to focus on the art that dominates the picture – in this case, we have Symbol of Life (released in 2002), its single Erased, and Believe in Nothing (2001).

Link to the official Paradise Lost web-page.

Symbol of Life and Erased are, at least to me, very interesting album covers. Yes, the animal in question is a snake, but it’s an x-ray of a snake. Now, I don’t know which species, or even a family, but I’m pretty sure it’s a snake. I don’t know how these photos were made, but are really special and distinct. For a better view, you can visit this blog. Erased is done in a very similar way, only with different coloring scheme. The animal theme is also presen in the music video for the single – there are scenes of a cougar and something that I believe is Thompson gazelle (I might be wrong on this one). I don’t know in which ecosystem could these two ever meet, outside of Paradise Lost video.

A gazelle
Nick Holmes in his apparent natural state

(Photo by Tobias Adam on Unsplash)

Believe in Nothing cover is simply straightforward: it’s a picture of bees. To be more precise, it’s a picture of a honey queen bee surrounded with bee workers. I will go out on the limb and say the species is probably Apis mellifera, Western honey bee.


Another one of my favourites, Katatonia and their dark melodies have adopted a bird from the Corvus genus as a motif that often appears on their album artworks (Dead End Kings, 2012; Tonight’s Decision, 1999). They were also the main focus of one of the earliest Katatonia’s albums, Brave Murder Day (1996), and latest, The Fall of Hearts (2016). Just by looking at these, I honestly can’t tell if it’s a crow, raven, or something in-between, but it does compliment Katatonia’s music perfectly.

A crow
Insert random lyric about crows, ravens, or E. A. Poe

(Photo by Sergio Ibanez on Unsplash)


To me, Opeth always had interesting, dark album covers, but two caught my attention – art for their debut album Orchid (1995) and Sorceress (2016). For Orchid, the artwork is, you guess it, orchids; apparently the pink flowers on the cover were ordered from the Netherlands.
Sorceress is a different story – it shows a peacock with blood dripping out of his beak. This might seem odd, since most people, including me, always picture birds as eating seeds, but peafowls (name that includes male and female individuals, and three species) are actually omnivores, and their diet can include insects and even small reptiles.


Satyricon is a black metal band, with different sounds, and with that, different artwork. Some animal species, however, still remain!
On the cover of Nemesis Divina (1996) is a bird of prey, which one, I honestly can say. It could be a falcon, or a hawk, I have to admit that my bird knowledge is weak. Volcano (2002) album cover is kind of simplistic – in the main view, we have a head of a snake. At first, it looked to me like a python, but I actually believe it’s a boa, Boa constrictor even. For their 7th album, The Age of Nero (2008) they went back to their raptor roots and choose… Some kind of eagle?

Brown and black snake on a tree branch; black bacground.
Metal’s next top model

(Photo by David Clode on Unsplash)


Gojira is a death/progressive metal band famous for often including environmental themes in their songs. Their album From Mars to Sirius (2005) is completely dedicated to these issues, and as such, has a very nice album art, with the drawing of a blue whale (Balaenoptera musculus) being a centerpiece.


A heavy metal from Iowa, Slipknot chose a goat for the cover of the 2001 album titles Iowa. These kind of imagery is usually used by black metal bands (see honourable mentions, also Baphomet), but in this case, I think it works nicely.

A goat
Felt cute, might grow human limbs later

(Photo by Edgar Chaparro on Unsplash)

Honourable mentions

Bathory – Bathory (1984) – goat
Behemoth – Zos Kia Cultus (2002) – baphomet
Dimmu Borgir – Stormblåst (1996) – goat
Immortal – All Shall Fall (2009) – ravens?
Mayhem – Grand Declaration of War (2000) – dove

Nile – In Their Darkened Shrines (2002) – snake

Rammstein – Herzeleid (1995) – flower (chrysanthemums?)

Bring Me the Horizon – Count Your Blessings (2006) – jellyfish, shark, fish

The Rasmus – Hide from the Sun (2005) – butterfly

National Park – Plitvice Lakes

Since it is winter and exam season is closing in, I am not spending a lot of time in the lab (or anywhere interesting). Because of that, I wanted to write a short throwback post about last time I visited one Croatian National Park. Despite being a very small country, Croatia is rich in intact nature and preserved areas. The most famous of those areas are National Parks, and Croatia has eight! I also must mention, that in spite of popular belief, there are two areas more protected than National Parks – “strict reserves.”

The National Park I’ve paid a visit more than a year ago (November 2017) is called Plitvice Lakes, or simply Plitvice. The area is a National Park since 1949 and it’s Croatia’s biggest and oldest Park. It consists of 16 lakes that are connected by many waterfalls and cascades. The specificity of the Park is tufa – yes, I checked, that’s the word! 🙂 Tufa is a calcareous rock (meaning it is mostly made of calcium carbonate) and is porous. It is generated by precipitation of carbonate minerals out of water, and generally this type of rock is very sensitive to changes in pH. Why is it so special? Tufa forms barriers between the lakes! Those barriers are the reason why Plitvice are also part of the UNESCO World Heritage List.

Picture 1. A famous view on Plitvice Lakes

dsc_0040_Picture 2. Amazing waterfall in Plitvice

For the Chemistry lovers, here is a chemical formula of tufa formation:

Ca2+ +2HCO3 ↔CO2 + H2O + CaCO3

Apart from environmental factors, small organisms play very important role in the formation as well. There are bacteria, small multi-cellular organisms, blue-green algae (not algae at all) and diatoms (actual algae). Mosses are part of this ecosystem as well, together with many other smaller organisms, both animals and plants.

As I already mentioned, there are several factors important for the formation of tufa rocks, and pH of the water is the one you have probably heard about. The reason why is it almost exclusively mentioned is pollution that changes pH of the lakes. One of the main problems? Tourism. Yes, tourism. I won’t get in the detail about not-so-well-made sewer system in the whole area, but Plitvice are one of the most famous places in Croatia, and as such, receptible to huge numbers of visitors every summer. And sometimes, that people don’t follow basic rules of spending their time in nature, so a lot of littering and wild-life disturbance occurs. Don’t get me wrong, this National Park is open to the public and meant to be enjoyed, but sometimes it seems more emphasis is put on money, rather on educations. Because of that, I would sincerely like to ask all of you, to take care of our environment, especially when visiting a foreign country.

dsc_0068_Picture 3. Calm lake and some rocks. And trees.

dsc_0109_Picture 4.  View of a lake, before the boat drive

Anyway, back to my excursion! I was part of the group from my Department, as a part of the field trip for subject “National Parks.” It was a one-day trip, and we walked approximately 10 km around the lakes. The biggest lake is called Kozjak, and it is also a deepest lake. All lakes are beautiful blue-green colour and surrounded with walking paths and breath-taking views. The weather was a bit cold-ish, since it was November, but enough to walk around in a jacket and winter hat. And a camera of course! I tried to picture most of the nature and wildlife around me, but we didn’t see as much (again, because it was almost winter). However, Plitvice are rich in both flora and fauna – its symbol is a brown bear! Grey wolves and lynxes are also natural to the habitat, as well as many bird species – I’ve seen robins (Erithacus rubecula), some sparrows (Passer domesticus), and mallards (Anas platyrhynchos), but falcons (Falco peregrinus) and pygmy owls (Glaucidium passerinum) are regularly sighted. From other flying creatures, the Parks is full of butterflies (Phengaris alcon), bees (Apis mellifera), and similar (Calopteryx virgo), as well as bats (Barbastella barbastellus; there are also many caves in the Park!). There are many salamanders (Salamandra atra), otters (Lutra lutra; that I very sadly haven’t spotted), and fish. A lot of fish. I would also like to mention, that an endemic species was found in this area, in one of the caves – a small bug, Machaerites udrzali, which belongs in order Coleoptera. Forest(s) around the Lakes are full of common beech (Fagus sylvatica), but there are also firs (Abies alba), pines (Pinus sylvestris), and Ostryas. In fact, when it comes to flora, there are more than one thousand registered plant species, including dead-nettles and orchids. Mushrooms also have an important presence in Croatian forests, and Plitvice forest is famous for being a home to another rare species – saprophytic fungi Camarops tubulina.

dsc_0080_Picture 5. Mallards humbly asking for bread

So, what do you think? Did you know that this National Park is so full of life? Because I honestly didn’t, despite living in Croatia, well, my whole life. Of course, we were taught about some general facts during our schooling, but I was really surprised to learn how many different species live here.
Apart from such an important biological aspect, Plitvice Lakes are important in Croatian history as well, but I might talk about that next time!

Did you visit Plitvice, what were your experiences? How about some other Croatian National Park? Which one should I visit&write about next? 🙂

P.s. Yes, the header picture of my blog was also taken during this trip!