An animal trap comprising a trap (106, 102, 302) section having at least one moveable wall section (136, 228, 314), being moveable with respect to one or more other walls of the trap section to thereby alter the size of the trap section; animal detection means (138, 242, 306) operable to detect the presence of an animal within the trap section and adapted to signal such a presence to control means, which control means is operable, upon receipt of said signal, to cause movement of the moveable wall section (136, 228, 314) and thus alter the size of the trap section.