Ultra violet light. What we know and what we don't know.

Ultra violet light, unseen by us humans, is necessary for most reptiles in order to create the vitamin D they need for healthy bones and a good immune system. Too much of it can cause skin and eye damage. Too little or none of it can cause a lack of vitamin D which in turn produces a vital hormone that regulates bone health and also the immune response.
Many reptile keepers who don't have UV light try to get round the need for it by dietary supplement of vitamin D or by feeding food that contains vitamin D, such as whole mice and rats. But we still don't know how much UV light most reptiles need. Sometimes a UV light is put into the vivarium and lights up the whole of it so the animal cannot escape exposure to it.
Yet in the wild reptiles regulate their exposure to UV light. In the same way they regulate their body warmth by basking. They will bask inUV as long as they need and then shelter from it. Therefore captive reptiles must be given a hiding place, or the UV light must be applied in such a way that they can move from a "hot" UV spot to a "cooler" UV spot.
Most reptile keepers have caught on to the fact that there must be a temperature gradient within the reptile enclosure, so that the animal can choose whether to be in a hot spot or a cool spot. Now we need to provide them with a UV light gradient too.  The heat lamp and the UV lamp should not be combined. A reptile should not have to choose to get too much UV light in order to get heat, or visa versa.
Gary Fergus and colleague decided they would try to work out how much UV light a reptile needed by looking at the animals in the wild and seeing how long they spent exposed to it. It was not easy.
They concluded that keepers of captive reptiles should provide a UV light gradient from maximum to minimum (by providing a refuge). That care should be taken not to produce vitamin D overose by too much supplementary dietary vitamin D.
So far so good. But they highlighted the lack of exact knowledge.
1. How long does each species of reptile in the wild expose itself to UV light?
2. How much vitamin D does the diet of wild reptiles provide?
3. What is the natural circulating level of vitamin D in a wild reptile?
4. How far can the reptile regulate its access to UV light according to its level of vitamin D in the body? ie. does it "know" when its vitamin D levels are low and does it therefore spend more time in UV light?
5. How sensitive is the reptile skin of different species to the absorption of UV light and conversion into vitamin D?
6. What is the ideal level of vitamin D for each species of reptile?
We don't know.

*

Gary W. Ferguson,1 Andrew M. Brinker,1 William H. Gehrmann,1 Stacey E. Bucklin,1 Frances M. Baines,2 and Steve J. Mackin (2010) Voluntary Exposure of Some Western-Hemisphere Snake and Lizard Species to Ultraviolet-B Radiation in the Field: How Much Ultraviolet-B Should a Lizard or Snake Receive in Captivity?' Zoo Biology 29, 317-334.

How do you know if your lizard, or your snake, or your tortoise is stressed?

Muhammed Mahdi Karim photo is here

When animals are under stress, the nervous system responds by releasing adrenaline and other hormones to prepare the body for action. The adrenal glands flood the body with hormones like adrenalin (epinephrine) to prepare the animal for action. Similar hormones are produced in the brain.

For a long time it was thought that cold-blooded animals were “primitive” and therefore did not suffer from stress as much as “higher” animals.Yet reptiles respond in a very similar way to warm-blooded mammals, though their adrenal glands and their hormones are slightly different.

If the snake or lizard or tortoise has to run away, or hide, or do something in response to a threat, then these hormones help them to do it. For instance some lizards shed their tail when chased by predators. But if there is no action available, the hormones just flood the system to no avail. The animal has no relief from emotions like fear. Reptiles in bad conditions of captivity that cannot escape, for instance, will experience the emotion of frustration in countless escape attempts.

This means that they suffer.

And if the stress is chronic, this affects the animal’s welfare. Chronically stressed reptiles (and humans) have a lowered immune system. They are more likely to get various diseases and disorders.

One problem in measuring tis in reptiles is that their response will vary according to their temperature. They cannot produce their own body heat, so when a reptile is cold, its body functions slow down. So the stress hormone levels in a cold reptile will be different from the stress hormone levels in a warm one.

What can we look for? We can look for harmful repetitive behaviours, like the way lizards or tortoises repeatedly push at transparent barriers. We can look for lack of appetite, aggression, and even a change in skin colour in some lizards.  We need to know how a normal reptile behaves, before we can tell how a stressed one behaves.

What can we look for? Diseases and disorders due to stress may involve inability to reproduce, susceptibility to infections, emaciation from lack of appetite or its opposite, obesity.

What can we look for? We can measure the stress hormones or other chemicals in the blood, but taking blood samples, for instance, will cause even more stress. Or we can measure them in the faeces – a better way as it doesn’t hurt the animal.

But….. we don’t still know enough about what is normal for a corn snake, say, or a crocodile, or a boa constrictor, or a Hermann’s tortoise, or a bearded lizard. Each species may differ in the way it responds to stress. We have a lot of research to do.

Read

Silvestre, A. M. (2014) ‘How to Assess Stress in Reptiles, Journal of Exotic Pet Medicine, 23, 240-243.

Are reptiles intelligent? Can they learn? Amazing Reptile Fact 2.

Dr Anna Wilkinson with a bearded dragon. A still from Ingenious Animals
Available on BBC IPlayer till Sept 28 2016.

About 20 years ago I asked a so-called reptile expert whether snakes could think? "No," he replied. "They have a primitive brain."
"How do they find their way about?" I asked him.
"Instinct. Pure instinct." he replied.
Reptiles have a reputation for being stupid animals - " a lower form of life," more "primitive" than mammals, just a bundle of instincts, without feelings, unable to learn.
Wrong.
This slur on reptile intelligence came about for several reasons. One was the rather odd idea we have of the role of intelligence in evolution - a kind of tree of life with clever man right at the top, and all the other animals below, getting stupider the lower they appear. Like an intelligence class system - man as master of the world, animals as peasants or serfs. It's a self-important human idea. Even a mollusc, the octopus, can be pretty bright and may even be able to use tools, something we used to think only humans did. And although reptiles preceded mammals, they have been evolving since then. So even if they started off dumb in the days of the dinosaur (and we have no reason to suppose this) they have been evolving since then.
Work at Lincoln University, under the direction of Dr Anna Wilkinson, has shown that tortoises  can navigate their way through mazes. They can even follow the gaze of a fellow tortoise to find out where it is looking. Lizards can learn whether a food reward is on the left or the right. Tortoises can recognise the difference between a picture of food or the picture of a nonfood object.
Even more extraordinary is that a bearded dragon can learn from watching another bearded dragon tackle a problem. From a video, no less. This was demonstrated in a BBC programme, Ingenious Animals, in which one of Dr Wilkinson's lizards watched a video of another lizard pushing aside a glass door to get at some meal worms. Before he saw the video, he spent a long time trying to learn how to do this. Once he had seen the video, he got the idea far more quickly.
So.... reptiles aren't stupid.

Click here to watch the bearded dragon experiment on BBC until September 28 2016. The bearded dragon part is about two thirds of the way through.

Wilkinson, A.  & Huber, L., (2012), Cold-Blooded Cognition: Reptilian Cognitive Abilities,’ in eds Vonk, J. & Shackleford, T. K. The Oxford Handbook of Comparative Evolutionary Psychology, Oxford, UK, Oxford University Press, 129-143.

He's on his way.... Geoff the tortoise movie star.

Geoff, the tortoise your kids will love, is coming our way soon. Keep an eye out for him. He is the star of some mini films about tortoise welfare. Join this Facebook page to keep up to date - https://www.facebook.com/coldbloodedcare/

Looking through a glass darkly - can your lizard, tortoise or snake?

This snake has hiding places but the reflections might worry a chameleon.

Recognising ourselves in a mirror is something we take for granted. Or recognising that a glass door is a solid barrier (though drunk humans have been known to crash through glass doors!) Just because we can do this, we shouldn't assume other creatures can. Much suffering can be caused to reptiles kept in all-glass cages. Aquariums with four transparent walls are often sold as the right enclosure for reptiles.
But are they? Many lizards don't recognise that glass is a barrier and will make repeated attempts to push through it until they have injured noses. Green basilisks have a habit of just running into the glass full tilt. If you already have a four-sided aquarium  for your lizard, you must stick an opaque paper barrier on the outside of the glass in three sides. If your lizard is pushing at the glass in the front, think about doing the same for the bottom half of the glass there too.
The other problem with bog-standard aquariums is that they need a lot of extra equipment - escape-proof tops, UV lighting, arrangements for temperature gradients, etc. etc.  And they may be difficult to clean. So it is always better to buy a proper vivarium from a good reptile shop with all this built in, rather than just stick your reptile into cheap aquarium.
Chameleons have a different problem with glass. They can see their own reflection and think it is a rival. This is common with many species, even dogs and cats but these pets will generally learn to ignore reflections. Chameleons don't learn. Having a threatening rival within their enclosure is a constant worry to them. Moreover glass aquariums don't give them enough fresh air.
Tortoises feel much the same about transparent barriers. They will push like tanks against a transparent barrier whether it is glass or garden netting. If they can see a way through they will take it - somehow. They will also dig underneath it or round it. And a determined tortoise is very persistent indeed. So it is vital that any barrier is opaque, not see-through.

For snakes, a four sided glass enclosure is stressful for another reason. Snakes need hiding places - one in a hot area and a second one in a cool area. If they don't have them, they get very stressed. And chronic stress may mean they don't eat, or they get a respiratory disease.

*The human-reptile relationship - please help research by doing my survey at https://www.surveymonkey.co.uk/r/FGJZKLT

Help.... my tortoise is missing..... how to save its life.

Image from http://all-free-download.com/

Tortoises do go walkabout. And, worse still, they are easily stolen or picked up to be "rescued" by passersby who take them home. They can burrow under fences or  break through them like small tanks. Even tortoises kept in an indoor enclosure may find their way out and hide under a piece of furniture.
Sarah Joiner in central London lost her tortoise Zuma, aged 90 earlier this week. Luckily she guessed that he might have crawled into a black bin liner with the rubbish. She phoned Westminster Council who agreed to help.
Zuma was on his way to an incinerator, but satellite tracking by the council located the lorry in which he was travelling. After sear hing through one thousand black  bin bags for more than two hours, Sarah noticed some flowers she had thrown away poking out of one of the bags. Inside it was Zuma "on his back , legs flailing, looking incredibly indignant" she said.
Lottie a tortoise went missing for two years. Unlike the long journey of Zuma, she was found only a little way away. She escaped out of the garden into the neighbouring playing fields and was found in the far side. She had successfully survived and hibernated there. Because she was microchipped, her original owners got her back. 
So what to do if your tortoise is missing? A careful search in the garden, looking particularly for any fresh earth or in spaces like under the shed, may turn him up. Check the fencing for signs of burrowing or pushing through. (Remember that tortoises need opaque barriers. They will continue to push at glass or netting.)
And how to prevent it happening again? Check boundaries in the garden daily. A fence should be 8-12 inches below ground and high enough to prevent climbing - yes they can climb and will chimney up corners like a rock climber. Lock up your tortoises at night, just like you would your hens. They are like a meat pie with a hard crust for foxes and badgers. And dogs will attack them too, even the family dog.
Microchip your tortoise (yes, it is possible). And don't have a garden pond. Tortoises can drown in a pond. They can't swim. If you must have one, fence it off and cover it over. More vital information on how to protect your tortoise is here.
And please do my Reptile Relationship survey here.

The tortoise shell - an amazing story of evolution.

An early fossil of a tortoise that lived in South AFrican 260 years ago has been discovered. It has no shell though it shares other anatomical features with modern tortoises.  About 50 million years later fossils of tortoises with shells start to appear.
Dr Tyler Lyson of Wits University's Evolutionary Studies Institute, the Smithsonian Institution and the Denver Museum of Nature and Science explained: "Tortoises have a bizarre body plan and one of the more puzzling aspects to this body plan is the fact that tortoises have locked their ribs up into the iconic tortoise shell. No other animal does this and the likely reason is that ribs play such an important role in breathing in most animals including mammals, birds, crocodilians, and lizards."
Dr Lyson and his colleagues have shown that the modern tortoise breathing apparatus was already in place in the earliest fossil tortoise, an animal known as Eunotosaurus africanus.
This new species bridges the gap between the earliest proto tortises and the hard shelled tortoise of modern times.

This is how the hard carapice of the tortoise developed over the years. Watch the video here.

Download and read the scientific paper here: Tyler R. Lyson, Emma R. Schachner, Jennifer Botha-Brink, Torsten M. Scheyer, Markus Lambertz, G. S. Bever, Bruce S. Rubidge, Kevin de Queiroz. Origin of the unique ventilatory apparatus of turtles. Nature Communications, 2014; 5: 5211 DOI: 10.1038/ncomms6211
Or there is an easier version here.
If you have a tortoise or a snake or a lizard, do my Reptile relationships survey at  https://www.surveymonkey.co.uk/r/FGJZKLT 
and pass it on to others.