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School Trips

A visit to the Reptile Park can be of great value for students of all ages, showing the diversity of reptiles and giving an understanding how they are suited to their habitat and their response to environmental changes.
Guides are available for educational tours of the Reptile Park to answer questions and provide information about the animals as the tour proceeds.
The duration of the tour is usually about one and a half hours.
 

The following may be useful if drawing up worksheets and can be expanded during a visit.
 
 

Reptiles are one of the classes in the animal kingdom and they are currently represented by four orders, Crocodilians [crocodiles and alligators]  Chelonians [tortoises and turtles] Squamata [snakes and lizards] and Rhynchocephalia [tuataras]. Other orders such as the dinosaurs have existed in the past but are now extinct. 

How do we recognise a reptile?
  There are many characteristics that are shared by the various classes of vertebrate animals and some that are not. The class that exhibits the following three amongst theirs are known as reptiles.

         [a]     They will obtain their oxygen from the air.[Lungs not gills]
         [b]     They will be either completely or partially covered with scales.
         [c]      They will be cold blooded [ectothermic]

For example an alligator has scales, is cold blooded and breathes air so therefore it is a reptile. A kiwi has scales [on legs] breathes air but is warm blooded and therefore it is not a reptile, it is a bird. A snapper has scales, is cold blooded but it gets its oxygen from the water,so it also is not a reptile, it is a fish. The following table lists the more obvious characteristics and how they are shared by the classes.Birds

 Class 
Fish
Amphibians
Reptiles
Birds
Mammals 
    Skeleton
Yes
Yes
Yes
Yes
Yes
Fur/feathers
No
No
No
Yes
Yes
Scales
Yes
No
Yes
Yes
No
Gills
Yes
No
No
No
No
Lungs
No
Yes
Yes
Yes
Yes
Cold blooded
Yes
Yes
Yes
No
No
Warm blooded
No
No
No
Yes
Yes
Egg layers
Yes
Yes
Yes
Yes
Yes
Placental
No
No
No
No
Yes
Suckle young
No
No
No
No
Yes

How do these characteristics affect their lifestyle and survival?.
           [a]     Although some reptiles [Crocodilians, turtles and sea snakes] can spend some time underwater they must be able to get their nostrils above waterline for air from time to time. To make this easier some have developed long necks and most have their nostrils positioned in such a way they can be poked through the surface while the rest of the head and body is still underwater.
           [b]     Scales allow the reptile to bask and build up body heat without dehydrating. In some cases [mainly with lizards] the the scale ends with spine which if long can be useful defence or to regulate the amount of sun on the body. If threatened some rock dwelling lizards can wedge themselves into crevices by slightly inflating their bodies and those with small spines to their scales gain additional grip and are very difficult to remove.
           [c]      Being cold blooded means that it is unable to generate its own body heat and must obtain it from an outside source e.g. basking in the sun. This characteristic has a profound effect on the daily behaviour pattern of reptiles. Warm blooded animals [mammals and birds] spend a good proportion of their day obtaining food. About 2/3 of the energy from this food is used to keep the animals body at a definite stable temperature.
As reptiles are unable to do this their food requirements are much lower and the daily behaviour of a reptile has more to do with physically maintaining the temperature of its body at a suitable level. This is called thermoregulation and the reptile must do it by finding  places to bask that are warm enough to raise the temperature of the body for it function properly and also others for retreat when necessary to prevent overheating.  To obtain maximum exposure when basking some are able to flatten their bodies, increasing the area to absorb sunshine, some will turn the soles of the feet to the sun [the skin is thinner there] and generally most orientate themselves to the sun for best coverage. To prevent overheating crocodilians and some lizards will lie with their jaws open and lose some heat to evaporation from inside the mouth.

How do reptiles breed?
 All reptiles produce eggs which can have hard shells like those of a bird or else a soft plastic-like covering. These are generally laid in a place that has a temperature that is suitable for them to hatch, however with some reptiles the eggs are retained within the body of the female and the young produced alive. This is useful in climates where the weather is changeable, as it allows the female to move the eggs about to keep them at the best possible hatching temperature. A few lizards and some snakes will guard their nest and female crocodilians will assist their off spring at hatching time and guard them for some months afterwards but in the main reptiles have no maternal instinct and the young have to fend for themselves.
     In fairly recent times it has been discovered that in many cases the temperature the egg is hatched at can determine the sex of the young when it emerges. There is a median temperature, usually in the high twenties, which will produce both males and females and a temperature a couple of degrees either side of this will produce mainly one sex. This is not standard, in some species the females are produced at the higher temperatures and males at the lower in others it is the reverse.

How do reptiles protect themselves?
 Small reptiles generally need lie in the open to catch the sun for warmth, but this also exposes them to predation. To combat this some rely on their colour which can be a very effective camoflage and most can remain motionless for some time, others will bask close to some form of shelter and quickly retreat if disturbed.
 When threatened some lizards and snakes can inflate parts of their body, produce collars and crests to make them appear larger and present an open mouth, sometimes with vivid colours, to deter predators. These actions can be accompanied with an audible hiss. The venom that some snakes possess is more for offensive purposes than defensive, its main purpose is to prevent the snakes quarry from escaping after it has been ambushed. The venom needs to be potent enough to kill the prey quickly rather than it dying later and being lost to the snake. Constricting snakes do not need venom as they are capable of holding and suffocating their prey by wrapping their bodies around it.
 The shell of a tortoise almost completely encases the animal leaving only two openings, in the front for the head and legs and at the back for legs and tail, the top is called the carapace and the underside the plastron. It is part of the skeletal structure of the animal constructed of bone covered with a layer of keratin, enlarging as the tortoise grows in a similar manner as our own skull. It is strong enough to protect the body from most predators though a few birds will carry them aloft and drop them, cracking the shells. To protect the head it can be withdrawn and covered by the front legs, or in the case of box turtles the hinged part to the underside of the shell [plastron]can be closed.
 Crocodilians because of their size are relatively safe from predation and are quite happy to bask on the land without fear, if threatened however they can use their tail as a flail to trip the aggressor. Some of the larger lizards [monitors etc] also employ this whipping action.

What do reptiles eat?
 Because they do need it to maintain their body heat the amount of food reptiles need is about one third and and the time between meals less urgent than that of warm blooded animals of similar weight. In cooler weather as their bodies would be a bit stiff for efficient hunting and their metabolism too slow to process food even those that do not hibernate and are unable to raise their body heat to a suitable level can go through long periods without eating or eating just a small amount.

 [a]Lizards and snakes are for the most part carnivores [meat eaters] but there a are few species of lizard that are herbivores [plant eaters] and some do eat plant matter [berries, leaves etc] as part of their diet. Any suitable sized living creature, insect, reptile, mammal or bird that be swallowed, usually whole, can become a meal.
 [b]Land living tortoises are, in general, plant eaters grazing on ground plants and low growing shrubs. Turtles and terrapins are more inclined to be carnivorous though some are omnivores with plant food included in their diet
 [c]Crocodiles and alligators are meat eaters eating anything from fish to large mammals. Where the prey is too large to be swallowed it can be hidden underwater for it to soften and then pulled apart.
 [d]Tuataras are meat eaters, lizards, wetas, beetles, moths and other insects are included in their diet. Occasionally petrel chicks whose burrows tuataras sometimes share are taken.

What is the difference between a tortoise and a turtle?
  Tortoises are land animals and have strong legs suitable for walking and digging, in some cases quite extensive, holes in the ground. Some will soak in water occasionally but do not swim. They have oval dome shaped shells.
  Marine turtles are adapted to life in the oceans and with the exception of the females when laying eggs never leave them. Their legs are more like paddles than legs and cannot support the body although the female is [as with the other chelonians] able to excavate a nesting hole for the eggs using the rear limbs. Their shells are much flatter than those of the tortoises and taper towards the rear as an aid to swimming.
  To complicate matters there are aquatic and semi-aquatic chelonians that frequent fresh water streams, swamps etc. These are also referred to as turtles and/or terrapins. They and quite capable of walking on dry land as well as being able to swim efficiently. Most have webbed feet to some degree and the shells tend to be flatter than those of tortoises, more like those of marine turtles. In some species long necks enable them obtain air from the surface while their bodies can remain on the bottom of the pool..

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The reptile class is represented in New Zealand by animals from two orders Squamata [lizards] and Rhynchocephalia. Although sea turtles [Chelonia] and sea snakes [Squamata-suborder Serpentes] appear in small numbers on northern beaches they are not considered native as they do not breed here. Therefore the other two orders Crocodilia and Chelonia are not represented in this country. 

A question often asked is what is the difference between a lizard, a skink and a gecko.
 The word lizard denotes the type of reptile it is and the order to which it belongs. The lizards are grouped within this order into families and geckos and skinks are two of these. Other families are monitors, agamids [dragons], chameleons etc. but they do not occur in New Zealand.
 

There are about 26 families of lizards worldwide within the order Squamata and the lizards in New Zealand belong to two of these Scincidae [skinks] and Gekkonidae [geckos] . The Rhynchocephalia order has only one family Sphenodontidae [tuataras] and they do not occur in any other country.
There are about 35 species of New Zealand skinks, a similar amount of geckos and two species of tuatara currently recognised but these figures are under constant review as more research is conducted. 

How do we tell a skink from a gecko?
  The following are some of the differences that can be seen in New Zealand lizards.
    The scales on a skink overlap one another which gives a polished appearance and making them  smooth to touch. The scales of a gecko are smaller by comparison and do not lap giving the animal a matt appearance and velvety to touch.
    Skinks eyes have a moveable lower eyelid which enables them to close their eyes. Gecko's eyes are covered with a fixed transparent shield for protection and are unable to close them.
    Skinks are generally slimmer than geckos having a streamlined head as opposed to the rather frog-like head of geckos.
      Geckos have adhesive pads to their feet which enable them to climb smooth surfaces [even glass in some species] and although skinks can climb on rocks and trees they do not have pads to aid them.
 

How do New Zealand lizards breed?
  World wide geckos tend to live in the warmer climatic zones and lay eggs, the normal clutch is two. New Zealand geckos [and some from New    Caledonia] produce their young, normally twins, alive.
  With the exception of one species all New Zealand skinks produce living young, clutch size ranging from two to eight with some of the larger species. The lone egg layer lives in the Northern regions close to the sea and lays its eggs in sandy soil above the high tide mark. This lizard should not be confused with the small import from Australia [Rainbow skink] which is becoming common around the Auckland area of the North Island, it also is an egg layer.
  Tuataras are also egg layers and their eggs are noted for taking the longest time to hatch of all the reptiles normally in excess of one year. The eggs are buried at a suitable spot in the ground and left to hatch. There is no maternal interest after laying.
 

What do New Zealand lizards eat?
   Insects of various kinds are main item in their diet, supplemented the juice or pulp from berries. A few species will take nectar from flowers such as flax and in the North pohutukawa trees when in flower are an attraction to Duvaucels and  Northern Grey geckos. Species that live in proximity to seabird colonies will eat carrion in the form of fish regurgitated by the birds.
  Tuataras eat mainly insects such as wetas, crickets, moths etc.that are active at night as well as geckos and skinks of suitable size. Occasionally sea bird chicks are consumed by the tuataras that live with the colonies.

Why do lizards change their skin?
     The scales are made up of dead horny tissue formed by folds in the outer skin [epidermis] which has hardened and keratinsed and therefore unable to expand as the reptile grows. Usually it is cast as small pieces and the shed is not apparent, but in some species including our native geckos it comes off whole, usually in one piece. Even fine details remain intact,the feet are withdrawn leaving what would seem miniture gloves, the clear disc that covers the eye can be found and the scale patterning is easily recognisable.
     In the growing years these sheds [sloughs] may occur several times per annum but when adult normally only once.

Can lizards drop their tails?
      Both families of New Zealand lizards have the ability to what is usually referred to as lose part of their tails, some more readily than others. It is usually when the lizard is being physically attacked and the tail is held, however if provoked sufficiently some will do it spontaneously [Duvaucels Geckos for instance]. The discarded portion will writhe for some time and provide a distraction. Similar to the vertebra in the back the bones in the tail are small to allow it to flex and each bone has a weak part in it designed to fracture readily while the muscles also come apart leaving a serrated edge. There is virtually no bleeding. The time for the tail to regrow is variable depending on the time of the year the loss occurs, but with favourable conditions and a good food supply usually about a year. The new  portion does not grow bones instead the tail is supported by a length of cartilege and is not as long or elegant as the original. It is also capable of breaking and regrowing.
 

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