Virtual environments can feel lifeless or robotic, and a way to combat this is the inclusion of living creatures with life-like behaviour. Wanting to bring this into computer animation, Craig W. Reynolds formulated a model to simulate the flocking behaviour of birds. Delgado-Mata made extensions upon Reynolds’ flocking model, and his model has in turn been used to simulate a sheep herding scenario. The herding scenario can extend into many peripheral fields, where an effective strategy for a single agent to maneuver a large group of unwilling agents can have many applications. This study investigates whether Delgado-Mata’s model is able to simulate the emergent behaviour of a herd of sheep under threat more realistically with or without fear contagion. This was done by comparing the results from the simulations, made with and without contagion, with the empirical data of another experiment. A modified version of DelgadoMata’s model was implemented in Unity 3D. A simple fear contagion model was used. The parameters used in the flocking model were chosen through manual trial and error. Analysis of the positional data of the virtual sheep and dog showed that including fear contagion increased the realism of the simulation. A higher resemblance between the simulation with the fear contagion model and the empirical experiment was found. The difference between the two model simulations was however not large, and the subject can be further investigated. ; Virtuella miljöer kan kännas livlösa eller robotiska, och ett sätt att motarbeta detta är att inkludera levande varelser med verklighetstrogna beteenden. Med mål att införa detta i datoranimation skapade Craig W. Reynolds en modell som simulerar fåglars svärmande flockbeteende. Delgado-Mata har byggt vidare på Reynolds modell och hans utökade modell har i sin tur använts för att simulera fårvallnings-scenariot. Vallnings-scenariot kan användas i många relaterade användningsområden, där en effektiv strategi för en individ att manövrera en stor grupp ovilliga individer ...