Three quarters of Tanystropheus' body length was its neck and tail. If its neck had been any longer its head might have snapped off.
Tanystropheus lived in shallow waters but came ashore too. On land, Tanystropheus ate insects and small reptiles. In the water, it would gobble up fish and ammonites.
Tanystropheus was not a fast swimmer so often walked along the seabed and used its long neck to get within range of prey without being noticed. Like some lizards alive today, its tail could detach if seized by a predator, to allow an escape. It would then regrow.