Abstract: An animal vital signs detection system is provided which comprises at least one photoplethysmography (PPG) sensor (100) having at least one light source (110), at least one photo sensor (120) and at least one light guide unit (130) which is adapted to guide light from the light source (110) through hairs, fur or pelt to a skin of an animal (100) and light from the skin through hair, fur or pelt of the animal (1000) to the at least one photo sensor (120). By providing the light guide coupled to the light source (110) and the photo sensor (120), the PPG sensor (100) can be placed even on hair, fur or pelt of an animal (1000) while still being able to effectively direct light to the skin and detect light from the skin of an animal (1000). The ratio between a length and a diameter of the light guides is >4.