About a dozen people have been killed by salt-water crocodiles in Australia in the past 20 years. Now divers in northern Australia are calling for development of crocodile warning devices following two recent crocodile attacks. The numbers of crocodiles have increased rapidly in recent years, due to a ban on hunting passed in the 1970s. The deaths have also reopened debate as to whether limited limited hunting should resume. The salt-water crocodile (Crocodylus porosus) is the largest living reptile in terms of mass. There is a large population in Australia, with the majority being in the Northern Territory.