Over 350 species of ground-beetles Carabidae are recorded in Britain.  Of these, many are difficult to identify, but Carabus are easier, and with only 7 species known from Highland (3 of which make up 75% of our records) they are manageable.  Also considered is the related Buzzing Snail-hunter Cychrus caraboides.  The Caterpillar-hunter Calosoma inquisitor has been recorded a couple of times in Scotland: at Rowardennan in 1984-85, and at Spean Bridge in the 1960s.  For other genera see the link below.

Our species are usually easily recognised to the genus (see link below).  Most are large and bulky, more than 15mm and up to 30mm, so are often seen as they go about their business.  The Buzzing Snail-hunter has a distinctive narrow head and broadly oval body, and hisses loudly when handled.  All are carnivorous as larvae and adults.  If threatened, they release a foul-smelling cocktail of organic chemicals from glands near the tip of the abdomen.  This habit reaches an extreme in the Bombardier Beetle
Brachinus crepitans, not a Scottish species, where the release is explosive and may be fatal to other invertebrates.  Most species are mainly nocturnal, though are often active in daytime.