Aggression is an essential part of life and one of the most important topics in sociobiology. In our department, we deal with aggression on several levels. The most important is intraspecific aggression, which is associated with sexual selection and territorial defence. Our model species include monitor lizards (Frýdlová et al. 2017), eyelid geckos (Kratochvíl & Frynta 2002) and frog-eyed geckos (Suchomelová et al. 2015). Other projects focus on aggression in rodents. Comparing aggressive behaviour in different populations of house mice can provide insights into the social organisation in nature (Frynta et al. 2005). In another model species, the spiny mice, we study social stress as the reaction to a new, unrelated male in the group, the hierarchy in the group and the level of steroid hormones (Fraňková et al. 2012). We offer students the opportunity to participate in projects on aggression, the main advantage of which is working with live animals and solving interesting research questions.