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 charge for the tours is $8 per person [both the children and accompanying adults] with no charge for teaching staff.
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.
Fur or Feathers Scales Gills
Lungs Cold Blooded
Egg layers Plaecental
Suckle their Young
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 iguanas 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 50 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
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
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
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
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 some in 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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