1. Department of Animal Physiology, Veterinary Faculty, Complutense University of Madrid, 28040 Madrid, Spain
2. Department of Animal Medicine and Surgery, Veterinary Faculty, Complutense University of Madrid, 28040 Madrid, Spain
3. Clinical Psychology Unit (UNINPSI), Department of Psychology, Comillas Pontifical University, Calle Mateo Inurria 37, 28036 Madrid, Spain
4. Zoogical Area of Parques Reunidos Group, Casa de Campo s/n, 28011 Madrid, Spain
5. Bioparc Valencia, Avenida Pio Baroja 3, 46015 Valencia, Spain
6. Department of Statistics and Operational Research, Faculty of Mathematics, Complutense University of Madrid, 28040 Madrid, Spain