Home | Field studies and notes | Skinks Surprise Researchers – Baby Lizards Hatch Early When Disturbed

Skinks Surprise Researchers – Baby Lizards Hatch Early When Disturbed

Hello, Frank Indiviglio here.   Herpetologists studying Australia’s Delicate Skink (Lampropholis delicata) discovered, quite by accident, that this species’ embryos somehow sense danger when their eggs are disturbed.  In response, the tiny lizards erupt en masse – even if they are not quite ready to hatch!   Also employed by Red-Eyed Treefrog tadpoles (Agalychnis callidryas, please see photo) this unique strategy is just one of many new discoveries indicating that reptile and amphibian embryos are more aware of their environments than we imagined (the embryos of some turtles even seek heat within the egg – please see article linked below).  The fact that the Delicate Skink is a very common species, and that the discovery was made in a park near Sydney, Australia, also shows the value of studying animals that are near-at-hand – all hold secrets!

Delicate Skink

Uploaded to Wikipedia Commons by Peter Woodard

Natural History

The Delicate Skink is a small, greenish-brown lizard that flashes iridescence in sunlight.  This characteristic is responsible for its alternative common name, Rainbow Skink.  Native to eastern Australia and Tasmania, it is often found in gardens, city parks and similar habitats.  Aspirin-sized eggs deposited in flower pots and nursery soil may be responsible for the populations now established on New Zealand and Hawaii (where it has been dubbed the Plague Skink).

A Calculated Risk

Hatching early is risky, as premature young are smaller, and therefore less likely to survive, than those that remain within the egg throughout the normal incubation period.  However, when a wasp (in the case of Red-Eyed Treefrogs) or snake grabs an egg, the fate of the entire clutch may be sealed.  So it seems worthwhile to chance a mass escape – even if swimming and running abilities are not quite up to par.  A search with various crocodilians and turtles indicates that embryos communicate with one another and synchronize their hatching time.

The fact that the entire clutch of Delicate Skink eggs hatches at once may also indicate that some form of communication is being used.  Sudden, simultaneous hatching serves to confuse predators…but we have yet to learn how this is managed.

An Unexpected Discovery…and more to come

When herpetologists from Australia’s Monash University first witnessed this phenomenon, they found it hard to tell exactly what was happening.  In the course of measuring eggs, tiny Delicate Skinks burst forth, fled in all directions, and sought cover.  Further studies revealed that the unexpected hatching was not merely coincidental.  Handling the eggs sent danger signals, apparently via vibration, to the youngsters within.  (Red-Eyed Treefrog eggs are attached to leaves overhanging a pond.  When under attack, tadpoles burst from their eggs, fall into the water, and swim off).

Red Eyed treefrog

Uploaded to Wikipedia Commons by Charlesjsharp

It is not known whether other of the Delicate Skink’s 10 relatives, collectively known as Sun Skinks, share this amazing survival strategy.  This exciting discovery shows just how much remains unknown about even the commonest creatures. One thing is certain – a great many surprises await those interested in reptile and amphibian reproductive behavior!

Please check out my posts on Twitter and Facebook.   Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable.  I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.  

Please also post your questions and comments below…I’ll be sure to respond quickly. 

Thanks, until next time,

Frank Indiviglio

 

Further Reading

Turtles Seek Heat While in Egg

Red-Eyed Treefrog Communication 

2 comments

  1. avatar

    Do you have any information about the captive care of this very beautiful but sadly overlooked species? Also, can they be found commercially?

    ps. They are concidered invasives in New Zealand and Hawaii, but have they caused any actual harm? I remember reading that the main perceived threat in New Zealand is the possible competition with the native skinks, but the evidence are scant.

  2. avatar

    Hello,

    They are not kept very often, as far as I know. I don’t know of any introduced species that has not caused harm, but given millions of involved interactions, such things are had to document unless quite major and visible (i.e. Burmese Pythons in Fla), or economically important (introduced crop pests, human health risks, etc). I doubt there’s much funding for research into this species, unfortunately. Best, Frank

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About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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