August 2026

🤔🐟️🤯 CHOOSING FAST OR SLOW?

Our two most beloved species of bower-building cichlids, although closely related, make very different decisions in complex choice situations!

This is what we show in this new paper published in PNAS. In our experiments, we used carefully crafter 3D-printed snail shells but let's make it simple and talk about... chocolate!

Step 1: You enter a supermarket to buy chocolate. Of course, you have preferences: you prefer milk chocolate to dark chocolate, but you prefer dark chocolate to white chocolate; you also prefer your chocolate to be as cheap as possible. Similarly, our fish have preferences of colours and sizes to remove first from their bowers. They prefer to remove orange shells first over brown ones, for instance, and they always prefer to remove bigger shells first. The preference patterns are the same for the two species.

Step 2: You equally prefer chocolcate with nuts and chocolate with almonds. Now imagine you arrive in the aisle, and there are 3 nut chocolate bars left, but only one with almond! Naturally, your attention will be guided to this lone chocolate bar and you will choose it. This is called the oddity effect. We found it in our two species as well. So in simple choice situations, they make exactly the same decisions.

Step 3: Let's complicated things a bit! You prefer milk chocolate to dark chocolate. When you arrive in the aisle, though, you see that milk chocolate is more expensive than dark chocolate. How will you balance that? Well, our two species react very differently. One of them, the blue featherfin Cyathopharynx furcifer, just focuses on one feature. They want milk chocolate, whatever the price! The golden featherfin Aulonocranus dewindti, on the other hand, chooses milk chocolate half of the times and dark the other half. As if they were really taking into account all information available, and making a considerate choice. But are they?

Step 4: To verify whether the golden featherfin was considering all information, or was just overwhelmed and choosing randomly, we conducted anoter experiment: the decoy effect task. It's a cognitive bias often used in marketing and we humans fall for it almost every time! You are now in front of an expensive milk chocolate bar and a cheaper dark chocolate one. But there is also a third option, the "decoy": an even more expensive milk chocolate bar. Although this option should not modify your initial preferences between the first two options, it usually does and you will pick the less expensive milk chocolate bar. That's how supermarkets make you spend more money! And our golden featherfins? They do not fall for it at all! They choose rationally, carefully considering all information.

Even though closely related and living in the same environment, our two species thus make very different decisions in complex situations: one chooses fast, without considering all information, whereas the other one chooses more slowly but takes into account all features of the options. Now here is a question for you: which strategy is better? Think about it this way: is it better to make less informed decisions but fast, or more informed decisions but slowly? Answer: not one strategy is better than the other! It depends on the situation. That is the beauty of intelligence: it is impossible to create a hierarchy of intelligences! That is, if you can avoid the marketing manipulations in supermarkets...

April 2026

🏠️🐟️ GOING HOME

Can fish find their way back home?

This is the question that we have asked in this study led by the great Zoë Goverts. She compared three species of shell-dwelling cichlids from Lake Tanganyika and showed that they were not all equally able to find their way back to their home shells. Besides, some appear to give more importance to landmarks than others. I am very honoured to have been part of this project!

And you, can you always find your way back home? How?

January 2026

🐦‍⬛🎶💦 SINGING IN THE SHOWER

This time, rooks sing in the shower!

In this wonderful experiment led by Killian Martin, rooks could place themselves below sound showers and sing along the sounds coming from them. Some rooks showed interesting singing patterns, flexibly adjusting the rhythm of their vocalisations to the rhythm of the showers!

I am so thrilled to be a co-author on this paper showing once again that rooks' singing abilities have been so far underestimated.

August 2025

🐟️👀🐟️ TO LOOK OR NOT TO LOOK

Can fish learn from watching others?

In this study, we tested three species of shell-dwelling cichlids, caught from the wild in Lake Tanganyika, to examine this question. These species are very small fish which live in big empty shells on the bottom of the lake. First, we trained them to go inside specific shells to get a food reward. Then, we made them observe each other to see if what they saw mattered.

Turns out, they did learn to approach new scary experimental apparatuses quicker by watching others, but they kept their more specific choices personal. And you, do you prefer relying on what you know or on what you see others do?

February 2025

🤿🐠 FISH CAN RECOGNISE DIVERS

When you look at fish in the sea, have you ever thought that they could be looking back at you? Surely they can see you but they cannot get to know you, right? They cannot recognise you. Right? Right?

Many anecdotes suggested they can actually do it but we finally tested it experimentally. Very rapidly, wild fish learnt to recognise individual SCUBA-divers, reliably following the nice diver (the one who would give them food, of course).

So here are a couple of questions for you: Are you surprised that fish can recognise humans individually? Does it change the way you view fish? Why?

Check out the video below that explains how we did it!

June 2024

🐌⚔️🐠 FISH VS FISH VS SNAILS

We did it again! We tested whether bower-building fish in Lake Tanganyika could control their impulse to remove snail shells from their bowers. But this time, we added a new species: Cyathophraynx furcifer.

This new species was way worse than the other at controlling themselves. Interestingly, this difference in inhibitory control could be linked to differences in how they build their bowers.

Can these two species put aside these differences over their common hate of snails? Will they collaborate? Will they fight together? The snail war has just begun!

October 2023

🐌🐟️ GET THE (S)HELL OUT OF HERE!

Have you ever had a snail in your bed? If yes, you're either French or a fish that participated in our experiments.

We studied a wonderful species of fish in Lake Tanganyika: Aulonocranus dewindti. Males of this species build sand structures called bowers to attract females. And they hate when their bower is dirty! The public ennemy number one: snails.

We showed that if a snail shell and a stone were placed in their bower, they always removed the shell first. We then tested whether they would have enough self-control to refrain from doing so and learn to remove the stone first. The least we can say is that it was not easy for them! But some did. Think about that next time you find a snail and a stone in your bed.

February 2023

🐦‍⬛🎶💦 SINGING IN THE BATH

Do you believe corvids cannot sing? Think again!

In this study, we show that rooks do sing and that they love to sing over loud noises - like the sound of their bath being filled with water! More impressively, they can synchronize their vocalisations to the rhythm of the water noise. We're not the only ones singing in our bathrooms!