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.

Birds have their nests, so do some reptiles.

Model of a dinosaur nest

Birds take care in choosing and making their nests. The successful hatching of the eggs and the survival of the young ones depend upon it. Egg-laying reptile also need to choose their nests with care. If they lay their eggs in the wrong place they may never hatch or survive after hatching.
The typical birds' nest is a construction of twigs, grass, leaves sometimes lined with mud or feathers. Reptiles don't do this. Instead they find a promising spot and dig a hole to lay their eggs in. Or put them in a burrow. Or pile up material to make a mound. Some lizards just lay eggs in cracks in the rock.
Some, the yellow spotted monitor lizard, dig complext tunnels or warrens where several lizards can deposit their eggs. Crocodiles heap up rotting vegetable matter and lay their eggs on the top of it. The nest is usually at the water's edge so that the hatchlings can get to the water easily.
Turtles dig a hole and lay their eggs in just one night. But Tuatara and green Iguanas will spend several nights constructing a proper burrow for their eggs. If they don't get it right, the eggs may never hatch. The longer incubation period required for reptile eggs puts them more at risk than birds' eggs.
Unless warm blooded birds that sit on their nests to keep the eggs warm and hatch them, most reptiles do not brood their eggs. So it is all the more important that they lay the eggs in a place where they will be warm enough. This means that there must be the right balance of sunlight and shade for eggs that are laid in the open air. Burrowing reptiles can make the burrow shorter or deeper according to th temperature they need.
The warmth of a nest site affects the offspring - the size and even the sex. Unfortunately because reptiles rarely brood their young, the individual reptile cannot know if her eggs have hatched successfully. If birds lose a clutch, they will often find a different nest site and lay second clutch of eggs to compensate. Reptiles can't do this.
Therefore climate warming is likely to affect reptiles more than birds -- and may alter sex ratios drastically.

*Refsnider,J.M., (2016), 'Nest choice and nest construction in reptiles,' Available at www.avianbiologyresearch.co.uk
Paper 1500632 doi: 10.3184/175815516X14490631289752
Accessed November 4 2016.

Ultraviolet light - your lizard needs it for communicating..... don't keep it in the dark

RobinSings. https://en.wikipedia.org/wiki/Puerto_Rican_crested_anole

Lizards can see colours that we see and they can see colours we don't see - the colours in ultraviolet light. And colours matter to them, because they communicate with each other using colour signals. If they couldn't see ultra violet colour, it would like being colour blind for a human. And worse, because where we use words, they use colour to "speak."
Anoline lizards, arboreal American lizards, use their dewlaps to communicate.  They open and close them, making a sort of colour flash, rather like (but not very like) light signals used in morse code from ships. The brightness of the colours and how they stand out from the background makes them effective signals. Male lizards sit up on a high perch or branch, and flash their dewlaps to attract females and deter male rivals from a distance. Dewlaps are coloured differently in different species, probably to make sure that they show up in different habitats.
The females and rival males "capture" the signals with their eyes which have special cones. One type of cone is specialised for ultraviolet light. (Humans don't have this kind of cone.) Scientists tested Puerto Rican crested anoles to see what happened if there was no ultraviolet light visible. The lack of ultraviolet meant that the signal looked less bright to the lizard. The signal (which simulated a dewlap flash) just looked dark against the background.
Moreover, ultraviolet light helped the lizard detect motion. A dewlap flash is only a flash if it stops and starts, so detecting motion is important. Detecting motion in all animals, including humans, seems to depend on the contrast between signal and background which is more noticeable for a lizard sees the ultraviolet light.
So if we are keeping lizards in vivariums with no ultraviolet light - or where the UV lighting has failed - we are keeping them in the dark. Not only are they not getting the UV light they need for vitamin D (which means low immune system and poor bones), but they are living in a dull dark world where they cannot communicate properly.

For more read:  Fleishman, L. JJ. & Persons, M., (2001), 'The influence of stimulus and background colour on visisbility in the lizard, Anolis cristatellus, The Journal of Experimental Biology, 204l 1559-1575

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.

Too much or too little vitamin D for reptiles? What do we know so far?

Some lizards may use basking not just for heat but for UV light.

By now most reptile keepers realise that too little vitamin D is bad for reptiles. Vitamin D is either absorbed through natural light or through the diet. Although carnivorous reptiles can get vitamin D in their diet: strictly herbivorous reptiles will not get enough just from diet. And it now looks as if relying on diet along, even in carnivores snakes, risks vitamin D inadequacy.
What do low levels of vitamin D do? Vitamin D is important for the growth and development of bones, for the immune system, artery and vein health, and reproduction. So low levels will impact badly on all these functions. We now know for sure that good vitamin D levels are important for the successful reproduction of several captive reptile species.
Vitamin D can be found in supplements that are given to reptiles. But there is a downside to this. It looks as if dietary vitamin D can lead to too high a vitamin D level if supplements are used incorrectly. In reptiles with an overdose of vitamin D, the aorta gets furred up with minerals.  So supplementing vitamin D by diet can be tricky.
Vitamin D levels are also affected by ultra violet light. But there have been no reports yet of vitamin D overdosing because of UV light. Yes, there can be skin damage from "too much" UV light but not vitamin D overdose. There seems to be a mechanism in the skin hat prevents overdose.
So.....
It is safer to use UV lighting or access to natural daylight to give your reptile enough vitamin D. The animal can probably regulate its vitamin D levels to prevent overdose.
Moreover, some (probably not all) carnivorous captive reptiles that get their vitamin D from a diet of mice etc. may well benefit from UV lighting as well. Carnivorous Komodo dragons get more vitamin D from UV light than dietary vitamin supplement. Conversely ball pythons were able to get their vitamin D equally well from either.
What is the take-home message from this? Use of dietary supplements may not be enough and risks overdose if used incorrectly. UVB light on its own will not lead to overdose and is therefore safer. Some reptiles will benefit it even though they get vitamin D from a carnivorous diet.
AND MOST IMPORTANT OF ALL - Keep up with modern developments. This is an area which is still being researched. What was best practice ten years ago is not best practice now. If you think you know it all, you probably don't.

To read more about this go to:

Watson et al (2014), 'Vitamin D and ultraviolet B radiation considerations for exotic pets,'Journal of Exotic Pet Medicine, 23, 369-379.

 

How iguanas need their vitamin D - from light or a supplement?

There are two ways to get vitamin D - eat it or absorb it through the skin from light. Does it matter which? In the wild green iguanas would regulate their body temperature and their vitamin D by basking in the sun (an ultra violet light source) then going to the shade (without ultra violet light) when too hot. As they are herbivores they cannot get the vitamin from their food.
In 2004 a study suggested that dietary supplements of vitamin D were a good source rather than UV light. The problem with UV light then was that a reliable source of light was then not available.
You will find the details of the study here - http://www.anapsid.org/pdf/jody-hibma-uvb.pdf
In l996, a more complicated study was set up. This time different lighting was used and some of the iguanas showed very high levels of vitamin D, if they were given both a dietary supplement and an UV light. Strangely, though, these high levels didn't seem to poison them - though igs have been known to die of vitamin D overdose. Read the full account here - http://www.anapsid.org?iguana/bernard-d3.html.
So do iguanas need UV light and dietary supplements. They certainly need UV light and when you do put in UV light, you must give the iguana a place in the shade where it can escape the light if it chooses. It will regulate its temperature so the UV light needs to be in the same place as the heat lamp. If it is not the lizard will spend most of its time in the heat lamp area and miss the benefits of UV lighting.
Do they need a vitamin supplement as well? This seems to be doubtful. A lot of the general reptile supplements on the market will do them no good and may do harm. Again, read up on the topic here - http://www.anapsid.org/vitamin.html
It's difficult. It's complicated. And we don't know as much as we should. All this means that a green iguana is a pet for the experienced reptile person, not for a beginner.

Do corn snakes need or want ultra violet light? The vitamin D question.Pete Milligan of Evolution Reptiles

Pete Milligan of Evolution Reptiles, Kidlington

For years it had been thought that corn snakes, a popular and easy reptile pet, don't need special lighting. They just need a heat gradient and a proper diet of defrosted rodents.  The vitamin D which they needed came from their diet (just as cats and other carnivores get their vitamin D from their diet).
Vitamin D is essential for health. It regulates the calcium that is needed to make bones. Studies of vitamin D in humans and birs and mammals are beginning to show that it is essential for good health in other ways, possibly playing a protective part against human breast cancer. All in all it is an important vitamin.
We still don't know for sure how much vitamin D is needed by various reptiles. Do corn snakes need it via ultra violet light? Is their diet giving them enough? Corn snakes, if they are fed the correct diet (not the mince that was recommended as feed for snakes in Ireland in the l960s!), should have enough vitamin D to survive.  But what is enough? Enough to survive? Enough to breed? Enough to flourish?
A group of scientist in Louisiana State University investigated further (see below). Over 4 weeks during which the snakes were not fed, they exposed one group of snakes to UVB radiation, and one group were kept without it. They tested the level of vitamin D in the blood. The levels of radiation were also measured.
The group without UVB radiation showed no change in their vitamin D level: the group with UVB radiation had a higher level of vitamin D. So corn snakes can and will increase their vitamin D level if they are exposed to ultra violet light.There was no significant difference between the two groups in weight at the end of the period.
So now we know for sure that, given UV light, corn snakes will make vitamin D from it, and have a higher level of it in their bodies than a level just obtained from their diet. We can no longer make the assumption that UV lighting is unimportant for corn snakes. "The findings of the present study suggest otherwise," say the scientists. This is the first step towards finding out how important it may be and what levels are needed not just for survival but for good health and happiness (yes, reptiles do feel emotion!).
Pete Milligan of Evoluton Reptiles says: "A snake will benefit from UV - at the moment there isn't enough evidence to say that it is essential."

• The reptile relationship survey has now closed. Thank you everybody who did it.

• *Acierno et al., 'Effects of ultraviolet radiation on plasma 25-hydroxyvitamin D3 concentrations in corn snakes (Elaphe guttata),' American Journal of Veterinary Research, 69, 294-297

The third eye - is your pet reptile on a higher plane that you?

The "third eye"on a lizard - Wikipedia

The "third eye" was the seat of the soul, according to Rene Descartes, the French philosopher whose reductionist opinion of animals encouraged vivisection and other cruel animal experiments.
He couldn't have been more wrong. The third eye in reptiles is a functional adaptation which may allow them to "see" predators, like birds of prey, approaching from above. Its ability to function varies from species to species. In some it even has a lens and retina. In most reptiles the parietal eye doesn't have these but may be able "see" light and shade differences. There's a good description here.
The reptile parietal eye, connected to the pineal gland which is similar to the pineal gland deeper in the brain of mammals, responds to light and releases the hormone, melatonin, which regulates circadian rhythms like the sleep wake cycle. It influences the secretion of sex hormones too. And strangely it is the only bit of the middle brain that isn't paired. It's also got a good blood supply from a nearby artery.
In modern new age mysticism the third eye leads to  higher inner consciousness. With your third eye you see or experience stuff that ordinary non-enlightened humans cannot. Could your pet snake or lizard be on a higher plane that you are?

My Reptile Relationships survey is closing at the end of the month.

The third eye - not so much the seat of the soul as a way to regulate circadian rhythms.

The "third eye"on a lizard - Wikipedia

The "third eye" was the seat of the soul, according to Rene Descartes, the French philosopher whose reductionist opinion of animals encouraged vivisection and other cruel animal experiments.
He couldn't have been more wrong. The third eye in reptiles is a functional adaptation which may allow them to "see" predators, like birds of prey, approaching from above. Its ability to function varies from species to species. In some it even has a lens and retina. In most reptiles the parietal eye doesn't have these but may be able "see" light and shade differences. There's a good description here.
The reptile parietal eye, connected to the pineal gland which is similar to the pineal gland deeper in the brain of mammals, responds to light and releases the hormone, melatonin, which regulates circadian rhythms like the sleep wake cycle. It influences the secretion of sex hormones too. And strangely it is the only bit of the middle brain that isn't paired. It's also got a good blood supply from a nearby artery.
In modern new age mysticism the third eye leads to  higher inner consciousness. With your third eye you see or experience stuff that ordinary non-enlightened humans cannot. Could your pet snake or lizard be on a higher plane that you are?

My Reptile Relationships survey is closing at the end of the month.

Is my pet snake too fat? Or too thin?

Because we humans eat every day, it's difficult for us to get our head round the fact that reptiles don't need to. They need less food than we do because they don't have to heat up their bodies - the sun does that for them.
So many pet snakes end up too fat. Sometimes this is because their owners continue feeding them the same amount of food throughout their life. When they are young and growing, they need more than when they get to middle age - just like humans!! So if you feed your mature snake as often as you did when it was young, the result will be a portly animal.
With corn snakes, the fat is likely to accumulate just above the tail - look at the photo on the right and you will see the tail is growing out of a kind of bulge. That's usually a fat snake. If however it is an animal you have just bought, or if that lump occurs suddenly, then you need to take your snake to a vet to make sure it isn't some kind of illness.

The other mistake is not to feed your snake enough. That often occurs because if a reptile is kept at the wrong temperature without enough heat, their whole metabolism slows down. They lose their appetite and just go off their food. Slowly, their colours fade, their spine or ribs start showing and they become weak with starvation. Many of them will be dying before they get to a vet.
So how often should you feed your snake? How much? The detailed answers to this question depend on the snake's species. Get a good online care sheet from Evolution Reptiles here or from the RSPCA. Don't just rely on friends or forums  because the quality of advice will vary.
Finally, how do you decide if your snake is fat or thin or just right. Take a look at the very rough sketch below. It shows a cross section of a snake. The triangular shape on the left is a snake that is too thin - you may be able to see an outline of the spine at the top or even its ribs. The snake in the middle is the right size, a sort of dome-like shape with a flat bottom which is where its muscles pull it along the ground. The snake on the right is round all over - and too fat.

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.

How to kill your dragon - slowly and painfully.

This is a very sick bearded dragon,  brought into Evolution Reptiles in Kidlington.  It was probably in pain every single time it moved. It was desperately thin and its skin was a dull grey colour. It barely moved when handled. Bought off a Facebook page and it had been kept for three years without heating or UV light.
'It was very underweight," says Pete Milligan the owner Evolution Reptiles. "The spine was protuding and if you touched it it felt sharp. Each rib could be clearly felt. It was also lifeless when picked up."
He advised the owners to take it to a vet, sold a UV light to them, and discussed the lizard's welfare. Buying a lizard online (like buying a cat or a dog) is always dicey. They may come cheaper but the remedial vets bills will probably end up making these pets more expensive.
Other signs that the lizard was ill - its tail was flat not rounded: it had swollen joins on its feet: its elbows looked as if there were two elbows. Because it hadn't died quickly from lack of heat and UV light, its owner probably thought that it was OK to keep it that way. But the poor animal had survived in pain all that time.
"This all completely avoidable," says Pete. "People are still mistakenly thinking that reptiles don't need UV light. There are vivariums still being sold in which you cannot install UV lighting. And these are often sold with printed labels that give the wrong advice. It's time manufacturers got up to speed."

A healthy beardie with bright colours thanks to UV light

"The worst set up I see is tortoises that are kept without UV light. They are given Vitamin D supplement and people think this is good enough, but it is no substitute for ultra violet light."
Do my survey here:

https://www.surveymonkey.co.uk/r/FGJZKLT

Amazing reptile fact 1. Reptiles are cold blooded. Or are they?

Wikipedia

So reptiles are cold blooded. But not always. The Tegu lizard, Salvator merianae, from Argentina warms itself in the sun during spring and summer. At night they retreat to their burrows. In winer (April to September) they hibernate. At the end of hibernation in September the males emerge from their burrows ready to mate.
Their testosterone is high. The muscle in their face, which allows them to bite, swells ready for a fight.  Meanwhile the females are in the borrows, gathering nesting material and laying eggs. She guards them too - a kind of maternal care you see in birds and mammals.
This time of year, the tegus can heat themselves up and keep hotter longer, than would be expected just from basking. Birds and mammals do this all the time, so they don't need to bask in the heat. They make their own warmth.
So why is a reptile, cold-blooded, doing this?  Does this show evolution at work? Is this what was happening when the first mammals or birds emerged from the reptiles?

Read more at Tattersall et al., Seasonal reproductive endothermy in tegu lizards, Science Advances, 2016, 2. 1-7. Found at http://advances.sciencemag.orghttp://advances.sciencemag.org

How to choose a good reptile shop.

Pete of Kidlington's Evolution Reptiles. He runs a good shop.

1. Quick look round the premises to see if they are clean, well ordered with good reptile cages, not just a few old aquariums,  good selection of UV lights, free care leaflets (online or in the shop), hides, water bowls of the right type, etc. 
2. Specialist shops are usually better than general pet shops. Don't buy animals online. You don't know if they are healthy. Go and take a look first.
3. Do the reptiles in the shop have enough space, well ordered cages, UV lighting, basking spots, and places for snakes to hide. Or are they just kept in tiny plastic pots?
4. Is there are good amount of water. Enough for snakes to have their whole body submerged? Shallow but enough for tortoises to walk in so they can drink?
5. Are the staff willing to answer questions without blahblah- ing. Will they help you if you come in with a problem?
6. Do they sell books about the species you are buying.
7. Do they give a straight answer - ie. tell a first time buyer what reptile will be easy to keep? Or just sell them anything that the ten-year-old fancies?

Do my survey at https://www.surveymonkey.co.uk/r/FGJZKLT

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.

Silk back bearded dragons need extra care

Silk back bearded dragons are born without scales, just as Sphinx cats are born without fur. The result, for both pets,  is a skin without its natural protective coating. Just as Sphinx cats often have to wear knitted jackets if they are to keep warm, so silk backs need skin protection. Without the protection of scale, the skin is fragile and quite likely to rip.
Experienced beardie owners, Terry and Jodie Gomm, spend a lot of time caring for their two silk backs, pink Ivy aged five and yellow Rosie aged three.  "They are given moisturiser every two days to keep their skin supple," says Jodie. "And when they are shedding their skin, they are bathed not just in ordinary water but in Allogel." 
Good reptile shops like Evolution Reptiles in Kidlington will sell products that help reptiles shed their skin. It's always important to be careful about pulling off shed skin from any reptile: but with these silk backs it is essential not to do this at all. Their skin is so thin it tears easily.
Silk backs should never ever be bought as a first pet. They are too difficult to care for.

Sex and the single snake - who needs males?

From Wikipedia

Female reptiles don't always need to mate with males to have offspring. Snakes, Komodo dragons, and lizards have all given birth without sex. These have been females that were kept in zoos, labs or homes, and for some time people thought that parthenogenesis, the scientific name for virgin births, was the just effect of captivity.
But did this happen in the wild? It was difficult to know because some females reptiles can store male sperm for months or years, presumably waiting for a good time to be pregnant, ie a time when there is plenty of food and the right environment. So just because a wild reptile seemed to give birth without mating, it wasn't necessarily so. It was just delayed ordinary conception.
Then scientists, led by Warren Booth, examined 22 litters from broad banded copperhead snakes, A. contortrix,  and 37 litters from pit vipers, A. piscivorus, all from pregnant females collected in the wild. They did a DNA analysis and concluded this was automictic parthenogenesis. This probably means that when the original reproductive cell splits into two, the two new cells merge with each other and then start reproducing themselves (if I understood the process correctly).  The parthenogenesis found in reptiles like a blind snake and some lizards who automatically practice virgin birth is different and I will blog about this later.
This means that if a female snake or lizard cannot find a mate, she can give birth anyway. Aren't reptiles fascinating?  We mammals can't do this!

For more details read: Booth, W., Smith, C., Eskridge, P. H., Hoss, S. K., Mendelson, J. R. & Schuett, G.W., (2012), 'Facultative Parthenogenesis Discovered in Wild Vertebrates', Biology Letters, doi:10.1098/rsbl.2012.0666

If you have a pet or keep a snake, tortoise or lizard please do my survey at 

https://www.surveymonkey.co.uk/r/FGJZKLT

Why is your snake fainting?

A Youtube video of the death feint https://www.youtube.com/watch?v=9pm6hsIDXVc

The snake you are handling or are about to handle, suddenly goes limp and faints. It looks completely dead but it isn't. This is what Darwin called "the death feint." Or playing dead - though this is far from being a game for the snake.
The modern scientific term for it is "tonic immobility." Many animals including other reptiles and rabbits faint like this.
If an animal faces intense danger then an automatic reaction kicks in. There is a huge surge of adrenaline (epinephrine) and a reaction with what is commonly known as the five "Fs" - flee, fight, freeze, faint or fool about (ie do something odd which distracts the predator). Faced with being handled, a captive snake hasn't got the option to flee or to fight a large human. So fainting is one of the options left to it.
This death feigning reaction sometimes looks like a relaxed animal and ignorant rabbit owners think the rabbit is enjoying it.  Far from it. Rabbit owners are beginning to recognise this, as should snake owners. If your snake goes limp it is in utter terror.
Fainting is a last resort for an animal faced with a dangerous predator. With luck the predator will think the snake is dead and for a moment shift it's attention elsewhere. Then the snake has a chance to escape. This may work, for instance, with predators like the domestic cat.  If you watch a cat "playing" with a living mouse, when the mouse goes immobile the cat stops play for a little while. A cat's predatory drive is turned on by movement so sometimes the cat will poke the mouse to make it move so the play can continue. Cats that catch snakes often do a similar kind of playing around.
Patrick Gregory of Kent University tested the response of grass snakes to being captured. Snakes that were held by the tail rarely fainted when first grasped. Those held by the head were more likely to feign death. The larger the snake the more likely it was to remain immobile after being released. Perhaps because bigger snakes have less to fear about remaining still. The snakes that didn't faint would usually slither away as soon at they were released.
* More info at  Gregory, P. T., (2008),  'Bluffing and waiting: Handling Effects and Post-Release Immobility in a Death-Feigning Snake (Natrix natrix)', Ethology, 114, 768-774.

If you have read this far and have a pet reptile please do my reptile relationship survey at

https://www.surveymonkey.co.uk/r/FGJZKLT  Or put it on your Facebook page for others.

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.

Do you want a huge iguana living in your garden?

Green iguana - Wikipedia

Iguanas are moving into Florida thanks to its subtropical climate. They have also invaded Hawaii. These lizards are the descendants of pets that have been released into the wild. It is illegal to let them go but people still do it.

Mexican spiny iguana- Wikipedia

Now there are three species flourishing in south Florida - the common green iguana which can grow up to two metres long and weigh six or more kilos, the Mexican spiny-tailed iguana, which grows up to 1.3 metres long and the black spiny-tailed iguana about the same size but known as the fastest lizard in the world. The latter can look rather like alligators to people who are not familiar with the species.

Black spiny iguana - Wikipedia

Iguanas are herbivores mainly thought they will eat insects, birds eggs, and small animals. They will be happy to eat roses, bougainvillea, green vegetables, and courgettes from a garden.They burrow under pavements, leave droppings that may carry salmonella, and cause severe wounds by scratching and slapping their tails if people try to pick them up.

More details here
With thanks to Richard Adams, whose blog put me on to this. www.KeepingExoticPets.com
Do my survey here:

https://www.surveymonkey.co.uk/r/FGJZKLT

 

This amazing croc comes from Crocodiles of the World, a really good "zoo" that specialises in crocodiles and reptiles. Nothing else.
It is a zoo run by madly enthusiatic people , which grew out of one person's love for and obsession with crocodiles.  If you live in Oxfordshire you should make sure you don't miss it. A great place for kids too. Details at www.crocodilesoftheworld.co.uk
What I find weird about the crocodiles is their stillness. They are fast enough to pull down animals that come to the water to drink, but when they are not doing this they seem almost immobile. It's a great way to save energy. We could learn from them!
Did you know...

• Crocodiles can swim at 25mph just with the help of their powerful tail.
• Farmed crocodiles can reach 1.5 metres (5ft) in length in just one year.
• They sweat through their mouths.
• They have 24 teeth that are meant to grasp and crush, not chew. Like birds swallow grit, they swallow stones that grind food inside their stomachs, and also act as ballast.
• Most crocodile babies are eaten in the first year after birth, by large fish, herons, monitor lizards and even adult crocodiles.
• Some tribes in New Guinea, venerate the crocodile and give themselves scarring to match that of a crocodile skin.
• Crocodiles, first appeared 240 million years ago,
• They  can live up to 80 years.

PS. Crocodiles of the World is warm and sweaty just as crocs like it. If it's raining outside or cold, this is a great place to visit!

PPS. Do my survey on how your feel about your reptile  at https://www.surveymonkey.co.uk/r/FGJZKLT

New crocodilte species found in South Pacific - alas extinct. We probably ate it.

wikopedia

We are still finding the remains of large extinct animals - and this is one of them, the Mekosuchidae crocodile family (or, to be technical, possibly just a sub-family). This group includes one species which may have been a tree climber!
Mekosuchus kalpokasi the latest fossil discovery was a small croc, possibly one that lived on land rather than in the water. It was probably hunted to death when humans arrived three thousand years ago.
The jawbone was found in one of the islands of Vanuatu, (formerly the New Hebrides), 82 islands just southeast of the Solomon Islands. There is disagreement where the Meksuchian crocs fit into the family tree of crocodiles partly because there are only rare finds, though we know at least three species inhabited the South Pacific. Many species of crocs can live in the sea because they have salt glands in the tongue which can excrete the salt. So these kinds of extinct cros may have island hopped their way from Australia at a time when the sea level was lower and many small islands and coral reefs were above land.
Why is is extinct? Probably because the Lapita people arrived on the island and hunted it to extinction. Its remains were found at an archeological site suggesting that it was a food animal for the human arrivals. More detail here:

• Mead et al., (2002), 'New extinct Mekosuchine crocodile from Vanuatu, South Pacific,' Copeia, vol 2002, 3, 632-641. With thanks to Matthew Spriggs, one of the authors.

If you have a pet skink, or indeed a pet lizard, snake or tortoise, please do my survey which is here -  https://www.surveymonkey.co.uk/r/FGJZKLT

How to give your reptile a humane death.

grass snake killed by traffic

People are still killing their reptiles in ways that will cause unnecessary suffering - usually out of ignorance.   The problem is that we don't recognise the signs of pain in reptiles and because we don't, we think they feel less pain than we do. But their suffering may well be as intense as ours, and, when it comes to death, more prolonged.
If we keep reptiles for our amusement, we must be responsible for giving them as painless a death as possible.

These are the methods which are classified as inhumane and will cause suffering and pain.

•  Decapitation without anaesthesia. The head can live on for up to an hour, with the brain apparently still functioning and thus suffering.
• Freezing in a freezer without anaesthesia. Even if the reptile is placed in the fridge to reduce its mobility first, being put in the freezer will still cause suffering. The formation of ice crystals in the blood causes intense pain.

These are methods that are humane, according to the American Veterinary and Medical Association guidelines on euthanasia.

•  Injection of an overdose of pentobarbital at a dose calculated on a weight to weight basis.
• Three steps. Anaesthetise, decapitate, and then core through the brain. Called pithing this kill the brain tissue that would otherwise live on for some time possibly causing intense pain.
• Captive bolt or firearm for large reptiles including crocodiles.
• Blunt force trauma to the head, destroying the brain. This needs to be done by an expert. It has to be a strong blow.
• Rapid freezing in liquid nitrogen for species that are not freeze tolerant.

If you have a snake as a pet please do my survey at https://www.surveymonkey.co.uk/r/FGJZKLT