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Vitamin D3, UVB and Pet Reptiles: Important New Information for Pet Owners

Brown Anole

Uploaded to Wikipedia Commons by Hans Hillewaert

We’ve long known that many reptiles need Ultra Violet B (UVB) light exposure in order to manufacture Vitamin D3. Vitamin D3, which is essential for proper calcium uptake, is also present in many foods, and some reptiles can utilize it in this form.  However, there are some gray areas.  It seems that reptiles long considered incapable of using dietary D3 (and which therefore need UVB light exposure), can sometimes obtain D3 from their diet (please see chameleon and day gecko articles linked below).  Generalizations can be misleading – for example, the study summarized below shows that two anole species sharing the same habitat obtain D3 in very different ways.

 

Anole Study – Vitamin D3 and Basking Behavior

A study recently published in the Journal of Herpetology [47 (4) 524-29, 2013] examined whether the level of Vitamin D3 in the diet would affect the basking behavior of two anole species.  Earlier research had shown that Panther Chameleons do alter their basking behavior in response to blood levels of Vitamin D3; please see the article linked below for details.

 

Wild and captive Brown Anoles, Anolis sagrei and Stripefoot Anoles, A. lineatopus, living in Jamaica were used as study subjects.  When the D3 content of the diet was increased, Brown Anoles decreased the amount of time they spent basking in UVB light.  This remained constant over a 6 week period.  This indicated that they were obtaining enough D3 from their diet. When the dietary D3 was decreased, the Brown Anoles increased their exposure to UVB, so as to be able to manufacture D3 in the skin.

 

Stripefoot Anoles, on the other hand, did not decrease their basking time when fed high levels on D3, and they did not increase basking behavior when fed diets low in D3.

 

The researchers therefore concluded that Brown Anoles are able to use dietary D3, while Stripefoot Anoles cannot.  Stripefoot Anoles seem to rely upon the Vitamin D3 that is produced in their skin when it is exposed to UVB light.

 

Studies such as this show us that we must carefully research the needs of each species under our care.  Even if they are closely related, and share similar habitats, diets, and lifestyles, captive conditions that work for one could spell doom for another.

 

Madagascar day Gecko

Uploaded to Wikipedia Commons by Manuel Werner, Nürtingen, Germany

My Experience: Day Geckos Without UVB Did Well

I’ve made some related observations on Madagascar and Standing’s Day Geckos.  UVB exposure has generally been considered critical to their welfare in captivity.  Yet a colony of both, living at semi-liberty in a large zoo aviary, seems to be doing very well without access to UVB light.  Please see the article linked below for further details.

 

Providing UVB to Lizards and other Reptiles

Natural sunlight is the best source of UVB, but it is important to bear in mind that overheating can occur quickly, and that UVB does not penetrate glass or plastic.  Reptiles housed or placed outdoors must also be protected from rats, raccoons, dogs, cats, crows and other predators.  Where conditions permit, screen cages offer a great means of providing natural UVB to your pets.

 

t255908UVB Bulbs

In recent tests, the Zoo Med 5.0 and 10.0 Bulbs were found superior to several other models.  Mercury vapor and compact florescent bulbs generally emit higher levels of UVB than traditional florescent bulbs, and they broadcast it over greater distances.  Mercury vapor bulbs also produce heat, and so may eliminate the need for an additional heat source.

 

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

Chameleon Basking Behavior Influenced by UVB Needs

My Notes: Day Geckos Thrive Without a UVB Source

Using Compact UVB Bulbs

 Using Screen Cages

 

Chameleon Color Changes Predict Winner before a Fight Begins

 

Uploaded to Wikipedia Commons by  Mamboben

Uploaded to Wikipedia Commons by Mamboben

My grandfather cautioned me never to bet on a boxing match, as they were even less predictable than horse races.  But where chameleon fights are concerned, it seems that picking a winner is a simple matter.  A recent study revealed that color intensity and the speed with which a male can elicit color changes accurately predicted the winner of an aggressive encounter.  Furthermore, different areas of the body are used to covey specific types of information.  Chameleons know this, of course…which is why most contests end without physical contact between competing males.

 

Camouflage, Display, or Both?

Years ago, chameleons were thought to change color primarily to camouflage themselves from predators and prey.  In time, we learned that temperature, health, stress levels, dominance and other factors also played a role.

 

In recent years, researchers at Melbourne University discovered that communication, not camouflage, was the driving force behind the evolution of chameleons’ amazing abilities.  However, their work revealed that camouflage is involved as well.  At least one species, Smith’s Dwarf Chameleon, Bradypodium taeniabronchum, changes color when a predator appears…and the degree of color change varies according to the type of predator it faces!  You can read more about both studies in the articles linked below.

 

Female Veiled Chameleon

Uploaded to Wikipedia Commons by Geoff

Colors Convey Distinct Message

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Veiled Chameleons, Chamaeleo calyptratus  (which are unsociable even by chameleon standards!) were the subject of a recent study that examined color change and aggression (Biology Letters, 2013; 9 (6)).  Researchers at Arizona State University photographed and analyzed 28 distinct areas on the bodies of male chameleons involved in aggressive displays with rivals.  The brightness of the colors exhibited in certain body stripes foretold which of the chameleons would make the initial approach towards the other.  Head color intensity accurately predicted the contest’s winner.  The speed with which the various color changes took place also affected the fight’s outcome.

 

The vast majority of the staged aggressive encounters ended without physical combat. The rare battles that did occur lasted a mere 5-15 seconds.

 

Why Quit Before the Fight Begins?

I’ve read elsewhere that color change takes a heavy toll, metabolically, on a chameleon.  I imagine that a male who can quickly summon up a variety of bright, intense colors is viewed by rivals as being healthy and vigorous, and therefore not worth tackling.  Similar considerations may influence mate choice as well.

 

Threat posture, C. namaquensis

Uploaded to Wikipedia Commons by Yathin S Krishnappa

Seeing as a Chameleon Sees

Chameleons and many other creatures do not perceive colors as we do.  The Arizona State University study was the first to examine the effects of color change “through the eyes” of an animal.  Using a process that I did not completely (or, truthfully, even barely!) understand, specialized cameras and information concerning chameleon visual sensitivity allowed researchers to measure colors as they are actually seen by chameleons.

 

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

Chameleon Color Change: Advertising and Camouflage

 

Chameleon Basking Influenced by Vitamin D Levels in Blood

Veiled Chameleon Care

 

 

New Studies on Reptile Intelligence – How Smart is Your Pet?

Hi, Frank Indiviglio here.  I’m a herpetologist, zoologist and book author, recently retired from a career of over 20 years with the Bronx Zoo. A key indicator of intelligence is said to be behavioral flexibility – the ability to modify actions to fit new situations.  Long thought to rely mainly upon instinct, reptiles have not been credited with much “brain power”.  However, recent research revealed that many reptiles are capable of solving complex problems that are not “covered” by instinct, and can use what they’ve learned in the future (see NY Times; Nov. 18, 2013).  Although reptiles diverged from warm blooded creatures at least 280 million years ago, some meet or even exceed the problem-solving abilities of birds and mammals.  This will not surprise reptile owners, of course!

I’m often amazed by what I observe among the reptiles under my care, and would like to summarize some of that, and several interesting experiments, here.  I hope you will post your own experiences below.  This is a new area of research, so please feel free to boast, and remember that each new observation, however fleeting, has value.

Red-Footed Tortoise

Uploaded to Wikipedia Commons by H. Zell

Read More »

Reptile News – Surprising New Study on Snake Eyes and Vision

Hello, Frank Indiviglio here.  Herp enthusiasts are a lucky bunch, as we never need to wait too long for the next new discovery.  I’m especially thrilled by those that are completely unexpected, and which change “what we know” about animals and their lives.  The past few years have been especially productive, with news of Reticulated Pythons that regularly attacked people (Philippines), skin-feeding tadpoles, communal skinks, lung-less frogs and so much more (please see the articles linked below).  Recently, a Waterloo University researcher was startled to discover that snake spectacles (eye-caps) contain a maze of blood vessels.  These would seem to interfere with vision.  Intrigued, he investigated further…and made discoveries that broke new ground in snake biology.

Diamond Python shedding

Uploaded to Wikipedia Commons by Peter Ellis

Eye Caps Gain New Respect

Snakes view the world through fused, transparent eye lids known as the spectacles, brille or eye-caps.  Perhaps because they are shed along with the skin (please see photo), hobbyists and herpetologists alike have long considered them to be mere “goggles” that protect the eye while allowing for vision.  But we know have evidence that the spectacles are dynamic structures that assist in vision, and change according to the snake’s needs. Read More »

Spectacular New Species of Leaf-Tailed Gecko Discovered in Australia

Hello, Frank Indiviglio here. Madagascar’s bizarre Leaf-Tailed Geckos (Uroplatus spp.) are on the wish lists of many lizard enthusiasts.  Even after decades of keeping reptiles in zoos, I was shocked by the sight of my first specimen.  Equally unique are Australia’s fantastic Leaf-Tailed Geckos (genus Saltuarius).  In color, shape (some look like insect-chewed leaves!), movement and body position, both groups take camouflage to its extreme.  The recent (October, 2013) discovery of a new Australian species, the Cape Melville Leaf Tailed Gecko, has caused quite a stir.  Its Latin name means “exceptional, extraordinary and exquisite”…and it is very fitting! I know that I’m not alone in being thrilled that there are still such unusual creatures waiting to be found.

NE Australian rainforest

Uploaded to Wikipedia Commons by Adam.J.W.C.

A Tiny Range and Very Specific Habitat

The Cape Melville Leaf Tailed Gecko, Saltuarius eximius, seems limited in distribution to the Cape Melville Mountains on the Cape York Peninsula in tropical northeastern Queensland, Australia.

Only 6 individuals have been found, all on granite boulders beneath a rainforest canopy (please see habitat photo). This same mountain range is also home to 3 endemic (found nowhere else) frogs and 2 endemic skinks. Read More »

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