This is a list of the more unusual terms used on the tour. Once you've satisfied your curiosity, click the "BACK" button on your browser to continue the tour where you left off. Alternatively, you can jump to any part of the tour using the column on the right. alligator Alligators belong to the subfamily Alligatorinae. There are two species, the American alligator (Alligator mississippiensis) and the Chinese alligator (Alligator sinensis). They are characterised by wide snouts (relative to most other crocodile species). arboreal An arboreal species is one which spends the majority of its life living in trees. Green iguanas are arboreal, only coming to the ground on rare occasions, and usually to drop into the water and escape from predators. archosaur An archosaur is any member of the superorder Archosauria - a taxonomic grouping which includes the dinosaurs, pterosaurs, modern birds and, of course, the crocodylia. bait Bait is the food used to attract a crocodile into a trap. Many different kinds of meat can be used as bait, but the more usual ones include kangaroo, buffalo, wild boar and even fruit bats. bobbing Head bobbing is something that many reptiles do, but at the park you will often see our iguanas performing this unusual display. It involves nodding the head several times in quick succession - males have longer, more elaborate bobs, whereas female bobs tend to be shorter and jerkier. It can mean several things, but is normally a territorial signal. caiman Caimans also belong to the subfamily Alligatorinae and like alligators, have relatively wide snouts. There are 6 species of caimans, from tiny dwarf caiman species such as Paleosuchus palpebrosus, to the large black caimans (Melanosuchus niger). All are found in Central and South America. dewlap A dewlap is a flap of skin normally folded up under the chin. They are common in lizards, where the hyoid bones are used to extend the dewlap rapidly. Green iguanas are frill-necked lizards both normally extend their dewlaps as an aggressive or defensive signal. But the large surface area may also aid in heat absorbtion during basking. courtship calls Crocodiles are the most vocal of all the reptiles. They possess a wide repertoire of different call types. Alligators, for example, are known to produce over 20 distinctive kinds of sound. Saltwater crocodiles are not as vocally rich as alligators, but are still capable of producing some remarkable sounds. Alligators are well known for the distinctive courtship bellowing of males, which causes water to dance along their sides and over their back. crocodilians All living crocodiles, alligators, caimans and gharials are classified into the order Crocodilia, and are referred to as crocodilians. endemic Any species which occurs in only one country is said to be endemic to that country. If the species occurs in more than one country, then it is simply a native species, unless introduced from outside its historical range, which is a feral species. extant Extant means currently alive and is the opposite of extinct. Any species which still occurs naturally in the wild is referred to as being extant. There are 23 species of extant crocodilians today. feral A feral animal is one which has been introduced into a country or area (either accidentally or deliberately) and has established viable wild populations outside of their natural range. Feral animals can cause a lot of damage to ecosystems. One of the most famous is the cane toad, Bufo marinus. Feral animals are a serious problem in both Australia and New Zealand, and eradication programs for some species have been in place for many years. fertile Fertile eggs are those which contain a live embryo. Matural female crocodiles will, like many reptiles, produce infertile eggs in the absence of a male. fragmentation If a habitat becomes fragmented, then it is split up into smaller, isolated components. This is a serious conservation problem for many species which can no longer cross the barriers (e.g. an area of cleared or developed land) between fragments. gait A gait is a style of movement on land. Crocodiles have three classically defined gaits - the belly crawl, the high walk and the gallop, which are quite distinct from each other. gharial Gharials are members of the subfamily Gavialinae. They characteristically have a long, pointed snout lined with needle-sharp teeth - ideal for catching fish. Gharials are found in the Indian subcontinent. The false gharial, Tomistoma schlegelii, is similar in appearance to gharials but also shares many features common to true crocodiles. head-slaps During dominance and courtship displays, male crocodiles slap the water with their heads, "biting" the water at the same time. These both produce loud popping or slapping sounds, which carry for some distance in water - a clear signal to rivals. hole-nest Hole nests are the only option in areas where little natural vegetation is available. In Australia, saltwater crocodiles nest in the wet season with mound nests, and Australian freshwater crocodiles nest in the dry season with a hole nest. mature Crocodiles mature relatively slowly - most saltwater crocodiles are not sexually mature until they reach about 10 to 16 years of age. Sexual maturity in crocodiles is dependent primarily upon their size rather than their age. Faster growing crocodiles mature more quickly and are better suited for farming operations based on captive breeding. marine Marine species, such as hawksbill turtles, are restricted to the oceans and seas of the world. They are physiologically suited to live in saline (salty) environments. monitoring Monitoring is repeated surveying or counting carried out to determine whether populations are increasing, decreasing or stable, or whether their range is expanding, contracting or stable. monogamous Animals which form a single breeding pair and mate for life are monogamous. Dominant male crocodiles will mate with as many females as they can during a breeding season, and are polygamous. mound nest Crocodiles lay their eggs in a hole in the sand, or in a mound consisting of vegetation and detritus. Each species uses one or the other strategy, with the exception of one species (American crocodiles) in one area (Florida) where both strategies are used. Mound nests are less susceptible to flooding, as the eggs are raised above ground level. nocturnal A nocturnal animal is primarily active at night. Diurnal animals are mainly active during the day. Crocodiles are usually considered to be nocturnal. omnivorous An omnivorous animal (omnivore) eats and digests both vegetable and animal foods. Green iguanas are herbivorous and eat only vegetable matter. Crocodiles are carnivorous and eat a wide variety of animals. Marmosets are omnivorous and eat both meat and vegetable foods. palatal valve The palatal valve is an extension of the back of the tongue which covers the throat and prevents water flooding into the throat when the mouth is open underwater. This valve can be opened whenever the crocodile wants to swallow a piece of food or breathe through its mouth. Crocodiles must lift their head out of water to swallowing. retina The retina is a layer of cells at the back of the eye. It comprises cells of two forms (rods and cones) which make up the visual image as light hits them. Crocodiles have a large number of rod cells making the eye sensitive in low light conditions. They also have a reflective layer at the back of the eye called the "tapetum lucidum". This layer allows light to pass over the retinal cells a second time, increasing their overall sensitivity. sustainable use To sustain anything is to "keep it going" and thus sustainable use is a use which can be kept going. With wildlife, uses cannot be sustained unless the wildlife is conserved, so many people agree that sustainable use = conservation. The Northern Territory of Australia was one of the pioneers with sustainable use of crocodiles along with Zimbabwe, Papua New Guinea and the United States. Wildlife Management International has been involved in the research and management needed to realise it. terrestrial Animals which spend the majority of their lives on land but cannot fly are terrestrial. Marine turtles evolved from terrestrial ancestors, but are now totally independent of the terrestrial environment, except for nesting. true crocodile Many people use the word "crocodile" to refer to any crocodile, alligator, caiman or gharial. The tag "true crocodile" is therefore sometimes used to refer specifically to any member of the subfamily Crocodylinae - for example the saltwater crocodile, the Nile crocodile and the freshwater crocodile. vertebrates Vertebrates are members of the Animal kingdom which possess a notocord (which in higher vertebrates develops into the backbone) at some stage in their life cycle, unlike invertebrates which do not. wet season In the northern parts of Australia, the year is split into the dry season and the wet season (which lasts from November to May). As the name implies, nearly all the rainfall in a year occurs during the wet season. This promotes plant growth, and is the time saltwater crocodiles breed. Many areas are prone to flooding during the wet season. If the wet season comes too early, freshwater crocodile nests usually flood before the hatchlings have emerged.