Unique New Zealand: reptiles and amphibians
New Zealand’s reptiles and amphibians have many unique adaptations and unusual life processes. Click on any of the titles to view short video clips and images to learn more.
Transcript
Tuatara
Introduction
ASSOC PROF ALISON CREE A tuatara is a special kind of reptile. Reptiles are one of the group of back-boned animals that live on land with 4 legs. They have dry scaly skin. And today, in the living reptiles, we recognise 4 groups. There’s the turtles, the crocodilians – that’s the crocodiles and alligators and their relatives – the lizards and snakes, and then the tuatara is the representative of the 4th group. The tuatara are the only representatives of that group worldwide now, so that’s why New Zealand is so special for that.
Acknowledgement: University of Waikato
Living fossil?
ASSOC PROF ALISON CREE I think there’s a misconception out there in the public's mind that tuatara can be described as living fossils, and scientists in the past have contributed to that – we’ve used the term, too, in the past – but today, many scientists think that term ‘living fossil’ is inaccurate. It gives the idea, I think, to many people that tuatara have been unchanged for millions of years – that, if you look at the living animal, it’s the same as fossils from 100 millions years ago or more. And we know it’s not the same – it’s not the same internally or in its behaviour or ecology as animals that lived in the past.
Acknowledgement: University of Waikato
Egg tooth
A juvenile tuatara has a horny (not calcified) egg tooth on its jaw to help it break out of its shell. This falls off shortly after it hatches.
Acknowledgement: Associate Professor Alison Cree
Skeleton
The vertebrae found in a tuatara spine resemble those in fish and some amphibians, rather than lizards. Their ribs have bony processes more typical of crocodiles than lizards.
Acknowledgement: Tāmaki Paenga Hira Auckland War Memorial Museum, Creative Commons 4.0.
Special skull
ASSOC PROF ALISON CREE At the top of the skull, there are 2 rows of teeth, and that’s really unusual – normally, you’d just expect 1 row of teeth in the upper jaw. There’s some differences there in the way they feed. A tuatara, for instance, when it catches food will actually catch food like that and slide the lower jaw like this, whereas a lizard has got more flexibility in the bones of the skull, and it can actually arch the bones over like that and meet them at the front of the mouth, and it doesn't move the lower jaw, just swallows – it chews a bit and swallows. So a very different way of feeding, and that may be one of the reasons why lizards are more successful today. There’s a lot more species of lizards than there are of tuatara and their relatives.
Acknowledgement: University of Waikato
Gecko
Introduction
ASSOC PROF ALISON CREE We have, in New Zealand, about 20 described species of geckos, but there are going to be, we know, more descriptions coming through, perhaps ending up with maybe about 40 species described in the future.
Acknowledgement: University of Waikato
Toes
In native geckos, the arrangement of the lamellae under the toes is different compared with most of their nearest relatives in Australia and New Caledonia. The lamellae are modified scales. They have microscopic bristles that help give gecko toes their gripping power.
Acknowledgement: Associate Professor Alison Cree
Making noise
ASSOC PROF ALISON CREE Geckos generally are more vocal than skinks, and, in fact, the name ‘gecko’ comes from an Indonesian word for the sound made by a kind of gecko that lives in Indonesia – sounds something like ‘gecko’. But our New Zealand species don't make that particular sound. They’re not particularly vocal, they don't talk too much, but they do sometimes chatter or squeak or make a few noises from time to time.
Acknowledgement: University of Waikato
Live young
ASSOC PROF ALISON CREE What makes New Zealand geckos special is that they’re live-bearing lizards, so unlike almost all geckos elsewhere in the world – and here I'm talking about the, sort of, 950 other species of geckos in the world – almost all, all but one of those is an egg-laying lizard. All our geckos in New Zealand are live-bearing. They do not lay eggs. Instead, the embryos develop inside the mother, and so the mother plays a very important role in carrying her embryos around, and it turns out to be for very long periods. New Zealand Geckos have adapted to living in cold climates and particularly down here in the South we find that some of them have pregnancies that last over a year.
Acknowledgement: University of Waikato
Frog
Introduction
DR PHIL BISHOP We’ve got 4 native species that live in New Zealand, and we’ve lost about 3 in the last thousand years or so since humans arrived in New Zealand, so there were originally 7 native species of frogs here. They are quite unusual, they have a lot of very special characteristics that other frogs don’t have, and they’re thought to be the ancestral lineage of all modern day frogs, so they haven’t changed really since the days of the dinosaurs – they were hopping around when dinosaurs were in New Zealand as well, so they are very special frogs.
Acknowledgement: University of Waikato
Tongue
DR PHIL BISHOP They don’t develop a tongue so much like the introduced frogs. They tend to lunge at things with their mouth open, and there is a different attachment. Introduced frogs have a tongue that is attached right at the front so it can flick it out a long way, whereas native frogs have their tongue sort of secured at the back, so they can just sort of stick it out a little bit, so they sort of open their mouth and lunge.
Acknowledgement: University of Waikato
Land lovers
3 of our 4 native species live and breed on dry land. Even the more aquatic species, Hochstetter’s frog, can survive on dry land.
Acknowledgement: Phil Bishop
Breeding
DR PHIL BISHOP They have a very interesting type of breeding behaviour, that the female lays the eggs, the male fertilises them. They don’t lay lots of eggs like normal frogs would do, and they lay their eggs on land, and then the male guards the eggs, and when they hatch out into little froglets – they don’t have any tadpole stage – the froglets climb on dad’s back, and he looks after them for another couple of months before they’re mature enough to go on their own way.
Acknowledgement: University of Waikato
Ears
New Zealand’s native frogs lack an external ear drum and middle ear. Although they can make chirping sounds, they don’t croak. Scientists think they use chemicals rather than sounds to communicate.
Acknowledgement: Phil Bishop
Eyes
New Zealand’s native frogs have round eyes instead of slits.
Acknowledgement: Phil Bishop
Life cycle
DR PHIL BISHOP Native New Zealand frogs have a very interesting type of life cycle. Most frogs will lay thousands of eggs and then disappear and leave the eggs to their own devices, and obviously you get huge mortality, whereas New Zealand frogs lay only a few eggs, but they look after them. They’re big eggs. After about 4 or 5 weeks, they’ll eventually hatch out into almost fully developed froglets with a little tail, so then – no tadpole stage, the tadpole stage happens in the egg – and when they hatch out, they’ve got this little froglet. And the little froglets then climb up onto dad’s back, and they sit on dad’s back absorbing their tails. A couple of months later, they are big enough and they hop away and lead their own lives. And that’s very different from the introduced species.
Acknowledgement: University of Waikato
Skink
Introduction
DR KELLY HARE New Zealand skinks are quite unique, but skinks are world wide. They live in all sorts of different habitats. They can be found on mountaintops – well, not right at the top, but close to the top of mountains – and they can be found down near the shore, they are found in forests and in open grasslands. They are found pretty much everywhere. But New Zealand skinks are quite unique.
Acknowledgement: University of Waikato
Long life
DR KELLY HARE In New Zealand, skinks can live for up to 14 years. No one really knows the maximum age that they can reach yet, but that is still quite a long time compared with lizards elsewhere.
Acknowledgement: University of Waikato
Live young
DR KELLY HARE The New Zealand skinks are quite unique in that they give birth to live young. So most skinks around the world will lay eggs, and we have got 1 species in New Zealand that lays eggs, but the rest of the skinks in New Zealand, of which there are around 33 species, they give birth to live young.
Acknowledgement: University of Waikato
Favourite foods
DR KELLY HARE Skinks will eat pretty much anything that moves. They will eat all bugs that can fit inside their mouth. They will eat fruit if it’s available. They will also eat carrion – if there is a dead animal around, they will eat that, some species. There is a few species that live on the rocky shore that will actually eat dead fish and stuff like that. It’s quite impressive what they can fit in their mouths.
Acknowledgement: University of Waikato
Acknowledgement
The Science Learning Hub acknowledges the contribution of additional images and footage from: Associate Professor Alison Cree, Professor Phil Bishop, Dr Kelly Hare, Professor Ben Bell, Department of Conservation (Photographers: Mike Avis, Rod Morris and D.Garrick) and Tāmaki Paenga Hira Auckland War Memorial Museum, Creative Commons 4.0 for this interactive.
