In English: Thursday March 14, the great primatologist Frans de Waal died. This is a very hard and sad loss for science worldwide and for all the people who, in one way or another, have been touched by his research, writings and thinking. Professor de Waal has made substantial contributions to our understanding of non-human animals and, at the same time, to our understanding of ourselves, humans.   His very rigorous observations of chimpanzees, bonobos, capuchin monkeys and multiple other primates allowed him to demonstrate that the distance between non-human animals and humans is much smaller than previously believed. In his books, de Waal demonstrated, for example, that chimpanzees could build, over months, very elaborate alliances and that these alliances, rather than the power of particular individuals, determined the distribution of power. He described the great diversity in sexual behavior of bonobos between males, between females and between males and females. It also showed how bonobos manage to maintain very peaceful and equitable societies, largely through alliances between females. He conducted experiments that went viral on social media and showed how capuchin monkeys have a clear conception of justice and injustice. It also demonstrated the role of reconciliation in easing conflicts and preventing the escalation of violence. Recently, in his book “Different”, de Waal managed to show how some chimpanzees can deviate from the typical roles of their biological sex and how other members of their group accept them without problem.   Last year, we had the privilege of hosting Frans and his life partner, Catherine, at the Universidad de los Andes for a week. Thanks to the Thinkers of the World fund, we had several specialized conversations, meetings with students, professors and directives, an exhibition of their photos and a large conference in which more than 500 people participated. In all these events, Frans was very generous, sharing all his knowledge, experience and wisdom with everyone who approached him to listen, ask him questions or ask for autographs and photos. In addition, we had a wonderful excursion to Cimitarra, in the Magdalena Medio region, with three professors and 12 students from the University. There, we were able to observe four species of monkeys in their natural habitat, as well as spectacular landscapes.   On our last day in Cimitarra, a group of around 30 capuchin monkeys passed by the road we were going and each, in turn, made an impressive jump from one side of the road to the other. Some females were carrying their babies, and they still made this huge jump. We were all surprised by the spectacle, even de Waal. And then, to top it off, a group of 12 yellow and blue macaws flew right above us. Today, I think it was as if nature greeted Frans and said “thank you, thank you Professor de Waal, thank you for listening to us, for seeking to understand us and for giving us a voice”.