Monday, 22 October 2007

#34 Observations of an Eastern Water Dragon

Having wildlife visit, or live in your garden provides a great opportunity to observe the habits of particular animals at length. A Water Dragon calls my fern garden home, and not only is he interesting to watch, he's also entertaining. My fern garden is on my back patio, so my resident dragon lizard can be easily seen basking, hunting and going about his daily life.

Are you talking about me?


When animals linger in my backyard for more than a fleeting visit, I give them a name - well I can hardly chat to my visitors without addressing them by name, can I? My Water Dragon is "Jacky", because upon first sight I presumed he was a Jacky Dragon (Amphibolurus muricatus), but comparing the two lizards, the differences are obvious.

This juvenile male Eastern Water Dragon (Physignathus lesueurii) arrived on my back porch in late February this year, disappeared for the three months of June, July and August for his winter rest (brumation), presumably in a sheltered spot in my fern garden, reappearing in late August.

Jacky crunches on a Green Carab Beetle (Calosoma schayeri). Presumably, lizards' taste buds are not well developed, because if this beetle tastes as bad as it smells, it should not make a very appetising meal.

Jacky has a routine: at first light he takes a dip in the pond in the fern garden, often sitting on a submerged rock with just his head out of the water. My pond is only small, so Jacky doesn't get the chance for a proper swim, but I have observed his swimming style: he tucks his limbs close to his body creating a streamlined form, and the side to side movement of the tail propels him through the water.

After his early morning swim, he perches on rocks at the front of the garden catching the morning sun, feeding on invertebrates at every opportunity.

In the afternoon when there is no sun on the garden, he often basks on a brick ledge in the sun, snatching hapless insects.

Teeth of an Eastern Water Dragon

Water Dragons (Physignathus lesueurii) do not lose and replace teeth throughout their life. They have a row of sharp pointed teeth adapted for grabbing and holding, fused to the jaw. The tongue is wide and thick. Both the tongue and interior of the mouth are pink.

I've seen my Water Dragon catch and eat cockroaches, slugs, worms, moths, ants, and a variety of small and tiny crawling and flying insects. He will only eat living invertebrates. He is extremely agile and swift.

Teeth of an Eastern Water Dragon


Scats (faeces) of a Water Dragon have a capping of white material at one end, which often becomes detatched. Droppings of my resident juvenile Water Dragon are about 10 to 12mm long.

Excrement of an Eastern Water Dragon













Learning to recognise scats of some locally common creatures, allows you to determine what animals visit your backyard. "Tracks, Scats and Other Traces - A Field Guide to Australian Mammals" by Barbara Triggs is a useful book.

Hearing of an Eastern Water Dragon

Reptiles do not have ear 'flaps' like mammals, but lizards have an external ear structure and therefore have adequate hearing.

The tympanic membrane, is a thin membrane that separates the external ear from the middle ear. The inner sinus in the middle ear cavity containing organs relating to balance and hearing, is filled with fluid in lizards and turtles, whilst in snakes, the recess is filled with air.

Airborn vibrations are picked up by the tympanic membrane. Snakes do not have a tympanic membrane, so can not 'hear', but detect substrate vibrations instead. The tympanic membrane of the Water Dragon is a small slightly-raised disc and can be seen in the close-up picture of the lizard head above. In some lizards, the Eastern Bearded Dragon (Pogona barbata), for example, the tympanic membrane is recessed.

An adult male Eastern Water Dragon


Hopefully, my resident Water Dragon will reach maturity and grow into a large impressive reptile as in the picture above. He will have to leave the security of my fern garden in order to grow to adulthood and breed.

But for the time being, Jacky must be eating well because he is currently moulting. Below is a series of images of the moulting process over two days.

The shedding of scales is called ecdysis, or, moulting or sloughing. Moulting serves a number of functions: my understanding is, firstly, the old and worn skin is replaced, secondly, it helps get rid of parasites such as mites and ticks. And as lizard scales do not grow with the body, moulting is necessary for growth.

The moulting started on the lower legs


The skin flaked off from bottom to top


At the end of day two, the skin peeled off the back


An Eastern Water Dragon (Physignathus lesueurii) is easily distinguished from similar dragon lizards by the presence of a thick black band running from the lower corner of the eye, extending over the tympanic membrane (ear), onto the neck.

A male can be recogised by the bright brick-red colouration of the belly. A male also has a more prominent spiny crest and more yellow patterning on the face and flanks.

I'm off for a swim


My resident Water Dragon is a regular source of interest and amusement as he scurries amongst the plants, leaping from vantage points to catch a feed. It is very satisfying to know that I am creating habitat for native creatures in my backyard that was a bare block of land a couple of years ago. I have recently planted many native shrubs and ground covers in an attempt to provide further habitat for small creatures and birds.

More Water Dragon observations and images can be viewed at my blog entry #12.

17 comments:

Anonymous said...

Hi Gaye,
Another delightful and informative blog, this time on Water Dragons. How wonderful for you to have "Jacky" close at hand to observe and photograph. He must be aware that his surroundings are safe. Well done!
Lola

Gaye from the Hunter said...

hi Lola,

thank you.

The more I get to know reptiles, the more interested in them and fond of them I become.

When I was a child, turtles were "boys stuff", and lizards were as scary as snakes. Now that I'm a grandma, I am sure to include my grand-daughters in all things nature. My 6yo grand-daughter is a real nature enthusiast in the making, and is full of questions and intelligent observations. It gives me much pleasure and satisfaction to pass on some of my enthusiasm and respect for our native fauna and flora.

Cheers
Gaye

Esperance Blog said...

Hi Gaye, just love those big feet. He is a very handsome fellow. About how long is he now and has he grown much since your previous blog on him?

Gaye from the Hunter said...

hi Jack,

I'm pleased you asked about growth, because I should have included growth details. When he first arrived here 9 months ago he would have been between 22 and 25cm from snout to tip of tail, and now he would be about 35cm. He hasn't thickened up a lot, but his tail is certainly longer.

Since finishing his moult today, he is very fresh looking with orange belly and white and yellow markings on his sides contrasting with the dark greenish-grey of his overall colour, so I need to get some up-to-date photos.

Cheers
Gaye

Denis Wilson said...

Hi Gaye
Nice post on Jacky. I don't get the large lizards here, just small skinks, and a few (not too many) Snakes.
The sandstone country (below the baalt) has more lizards. The Botanic Gdns in Canberra has a great collection of tame, but "wild" Eastern Water Dragons. Some of them are enormous. Tourists feed them. Its funny watching the Americans and Japanese going "nuts" over them.

Cheers

Denis

Gaye from the Hunter said...

hi Denis,

it really is a pity that tourists are allowed (and sometimes, encouraged) to feed wildlife. The food they are offered is nothing like the natural food of the animal.

I am not totally against the idea of giving the wildlife a helping hand with a meal (afterall, we humans destroy and degrade the natural habitat of these animals to the extent that they might struggle at times). But to allow animals to become dependent upon handouts can be detrimental to the animal, as can inappropriate food items.

Occasionally I will offer Jacky a live invertebrate, but he is an excellent hunter and has a very good strike rate.

I don't believe that Water Dragons are common in rural Hunter Valley where I live, but they appear to thrive in the rainforested environs of the Allyn, Williams and Gloucester Rivers.

Cheers
Gaye

Denis Wilson said...

I saw my first Water Dragon in this district today. Photo soon. It was in the sandstone plateau country, near a creek.

Funny that you have just written about them. It must be the season.

Denis

Paul Jackson said...

Hi Gaye,

Love those Eastern Water Dragons, I think they're magnificent little creatures (yes, I know they're not THAT little!!). I was first drawn to your blog by the "postcard" you had noted in the Australian Geographic newsletter enclosed with the magazine. What a great idea. As I also have a keen interest in nature and photography I think I might consider using your idea to try and promote conservation in the south-west Sydney suburbs.

Cheers, Paul

Gaye from the Hunter said...

hi Paul,

thank you for leaving a comment. Feedback is always very welcome.

Constructing and keeping a nature blog is a great way to promote nature, especially within the area you live so observations can be detailed.

Often people are not aware of the native animals and plants that they live amongst, so creating awareness of the beauty and diversity of nature, along with the fragility of the environment and specific habitats is a worthwhile project.

Residential settlement and industrial development is continually expanding and displacing native flora and fauna, so the more who realise what life is out there to consider and care for, the better.

And during the exercise, I have learned an enormous amount of interesting and useful stuff, as well as broadened my outlook on many subjects. Research is a fabulous way to increase one's knowledge base and enthusiasm. And then, there are so many other nature lovers out there who are happy and willing to offer assistance.

I can thoroughly recommend blogging about your local nature. If you go ahead with it, do please let me know, and if you need any tips on getting started, please ask if you think I may be of assistance (email facility is on my blog home page).

Regards
Gaye

macauleyk40 said...

hey gaye

thanks for your information i have a water dragon exactly like that his name is fred i found him hurt in queensland and he was giving to me as a present he now lives with me in am 12 and he is the BEST!!!

he loves to shed all the time and he is always fat is that good



P.S should i feed him frozen feeder fish out of my aquruium???

i freeze them and then defrost them.

Gaye from the Hunter said...

Hi Macauley,

I'm pleased you are enjoying your friendly Water Dragon. My Water Dragon gave me countless pleasure before he decided to venture back out into the big wide world, presumable looking for a lady with which to raise a family.

I am unable to confidently advise you on whether it is ok to feed your lizard frozen aquarium fish, as I do not know if your lizard is free-ranging and feeding himself, or whether you keep Fred in an enclosure of some sort.

Personally, I wouldn't feed him the fish, but then I also would not be enclosing the lizard, so there are completely different circumstances with a captive lizard or free-ranging.

My lizard was free-ranging, so fed himself (except for the times when I spoiled him with a native cockroach or worm or curl grub).

I'm sorry I can not be of more help to you.

Best wishes
Gaye

macauleyk40 said...

thank you gay and he is held in a extrem;ly big tank he is still onley a juvinile and thank you for your advive greatly appreciated

Jenny Moase said...

Hello, just found this blog by chance.We have a 10 inch lizard like yours living next to our pool in Adamstown. I am abit freaked by him because he runs towards us and then stops and just watches us and the dog! I am pleased he seems to be so happy in our backyard, no idea where he has appeared from, He climbs up the frangipanni tree and appears whenever we go near the pool, haven't seen him in the pool as yet.

Gaye said...

Hello Jenny,

how lucky you are to have a young water dragon living in your yard. Do take care that your dog doesn't become over zealous investigating this native animal, as family pets and lizards are generally not compatible.

Unfortunately, my water dragon was frightened by a visitors puppy, and natural instinct kicked in and the lizard disappeared. I was so pleased that natural instincts 'saved' the lizard after it happily lived in my patio garden for 18 months. He 'hibernated' twice in my garden - once in an unknown hiding place, and the second winter he tucked himself away in t he barbecue on the back porch.

It was a fabulous experience for me and my grand-children having this beautiful, active lizard living wild with us for such a long time, and a wonderful opportunity to observe his antics and learn about one of Australia's native reptiles.

Enjoy.

Cheers,
Gaye

Gaye said...

Jenny,

I forgot to include a link to more fun with my backyard water dragon - this entry is on my journal blog:

http://huntervalleyjournal.blogspot.com/2008/02/12-living-with-dragons.html

Gaye

Cassandra said...

Hi Gaye,
Well its 2012 and Jacky's legend still lives on.
My Husband and I have a very friendly 'wild' Lizard who swims in the neighbours pond but basks in our yard. We adore him and named him THIN after the makeup prouct thin lizzy.
He is very big and strong and quite comfortable with humans- we are unsure of wether the previous owner of the house fed him or not... My husband says we should leave him be and enjoy him from afar but id like to occasionally give him a treat ( any suggestions? ) We feed the local Lorikeets a nectar porridge and he seems to have a few licks of that but is not that interested...
He is just a delight to watch.
Thanks for your blog, i enjoyed reading it.
We have some great pic's of THIN that i will upload later,
Cassandra xo

Gaye said...

Hello Cassandra,

thanks for your email, and I'm so pleased to hear of your encounters with a backyard lizard. I miss Jacky, (he disappeared after 18 months in my garden when he was frightened by a visiting dog), but I imagine he's fathered plenty of cute little dragons by now.

If you wish to give the lizard a few treats, I suggest digging invertebrates from the garden or lawn (my lizard loved worms, native cockroaches, crickets, beetles - all live creatures, not dead ones). He hated millipedes and I remember him catching one and spitting it out - it was SO funny.

The main thing is not to make feeding wild creatures a routine, not every day, and not at the same time of day. If they become used to handouts, they can become dependent on them, and not only that, they might become a aggressive if they become too familiar with humans feeding them.

It is not a good idea to feed lizards 'human food' as they will be getting nutrients and products that their digestive system is not used to, and this could lead to health problems.

Enjoy the lizard, I know how lovely it is to have one close at hand to observe.

All the best for the New Year.

Regards,
Gaye