2004109 Crocodile Brochure - Department of Environment and ...

BIOLOGYCrocodiles have been on Earth for more than200 million years. They are a very ancient groupof reptiles whose ancestors were around beforethe age of the dinosaurs. They lived through theCretaceous period and successfully survived thegreat ice age periods of the last two millionyears. Perfectly adapted to their environment,today’s crocodiles differ very little from theirancient relatives.NESTINGThe estuarine crocodile usually nests during thenorthern ‘wet’ season from November to Aprilwhile the freshwater crocodile lays its eggs inlate August or early September.Both species are territorial and will defend theirnests against intruders. The females constructnests in which hard-shelled eggs are laid andincubated. Estuarine crocodiles construct avegetation and soil nest in which up to 50 eggsare laid. Freshwater crocodiles excavate a holein sand or other soft soil and lay between 13and 15 eggs. The incubation period is threemonths for both species.Many factors affect the survival rate of youngcrocodiles; only a few ever reach maturity.Floodwaters may inundate and drown eggs andyoung crocodiles are often taken as food bybirds of prey, goannas and dingoes.CONSERVATIONHunting for skins after 1945 caused a drasticdecline in the crocodile population. In 1962,freshwater crocodiles were given protectionfrom hunting in Western Australia and in 1970protection was given to the estuarine crocodile.Both species are now well on the way to recovery.There are two crocodile farms in WesternAustralia that take crocodiles from the wildunder licenses based on the guidelines ofCALM’s Crocodile Management Program. Thisprogram helps ensure the survival of crocodilesand maintains their role in the ecosystems inwhich they occur. This is accomplished in amanner unlikely to cause irreversible changes tothe species themselves or their habitat.PROTECTIONThe two species of crocodiles that occur inAustralia are fully protected by state, nationaland international legislation. Poaching, killing orinterfering with crocodiles, their eggs or habitatis an offence carrying penalties of up to$10,000. Incidents should be reported to yourlocal CALM office.WHERE CAN YOU SEECROCODILES?Freshwater crocodiles are relatively commonwithin their range. Western Australia probablyhas the largest population because of the widerange of suitable habitats, such as the massiveArgyle and Kununurra lakes created by the OrdRiver dam system. ‘Freshies’ can be seenthroughout the Kimberley in gorges andfreshwater billabongs. Early morning and in theafternoon are the best times to see them asthey bask in the sun or float in the shallowssearching for food.The estuarine crocodile can be difficult toobserve in the wild, owing to its shy nature.However, in certain areas it is possible to seethem basking on mud banks and swimmingduring the day. Do not approach these animalsclosely. ‘Salties’ can move with amazing speedand are generally much more territorial thantheir freshwater cousins.Estuarine crocodiles are predators andwhen entering their habitat the individualtakes all the responsibility for personnelsafety. Crocodiles always have theadvantage, so observe them from a safedistance.CROCODILE WARNING!Throughout the Kimberley region and parts ofthe Pilbara region you may see these signserected on tracks and roads, or when enteringknown crocodile habitats. The signs may also befound near boat ramps and at access points totidal influenced waterways and rivers.However, the absence of a warning sign doesnot signify that it is safe to swim or carry outother water based recreation activities such ascanoeing, fishing or boating.When you enter the Kimberley or Pilbararegions, you are entering crocodile country. Seeklocal advice from your local CALM office and becrocodile wise in your behaviour.PROBLEM CROCODILESIn Western Australia, problem crocodiles areconsidered to be those actively presentingthemselves as a threat to humans. The decisionas to what to do with such an animal is madeon a case by case basis. When appropriate,problem animals are caught and relocated toone of the crocodile farms. Crocodiles generallycannot be relocated to another area due to theirterritorial nature. If released they will invariablyreturn to the spot they were captured.Very often, problem crocodiles are betweenone-and-a-half and three metres in length, asize category known to be very mobile. Most ofthem would have travelled long distances insearch of safe territory before entering areaspopulated by humans.