Hypomelanistic Grass Snake | World’s First

Authored by Christian Castille

World First Hypomelanistic Natrix Captive Breeding

Natrix tessellata

Courtesy of Christian Castille

It will come as no surprise to most European herpetoculturists the grass snake is one of the most recognizable and loved snakes in Europe. For the UK, it’s one of our only three species of snake, which also include the adder and the smooth snake. I spent most of my life finding these snakes in situ, and breeding them in captivity. So you can understand my excitement when the herp world was rocked when I hatched out the world’s first ever captive bred hypo grass snakes back in August.

I’ve caught species of Natrix in multiple countries, from Viperines (Natrix Maura) in south of France to Dice snake ( Natrix tessellate) In eastern Croatia. However nothing beats herping for Natrix natrix, which as a person living in the UK, of course Natrix natrix helvetica, also known as the British grass snake is what interests me most. Its only natural to gain the most interest and excitement in herptofauna native to your own ecosystem.

For some 20 years finding these snakes in long grass, under logs, and in canal systems has been less of a hobby and more of a vocational calling. This coincides with all the other herping trips discovering more unusual and exotic reptiles,inverts and amphibians too. With being an allotment holder and managing multiple wildlife reserves in Staffordshire it has become a regular sight discovering grass snakes over the years. From having them basking on the stones alongside my ponds, to finding them brumating and even egg laying in my compost bins, it is a sight that never becomes old, dull, or boring!

Like most keepers, their interest is sparked as a child, catching anything and everything and keeping them for a few days at a time in plastic storage boxes and such, before letting them go days later. It’s a very fond memory which I think herpers from all over the world can relate to. Tadpoles in jam jars, frogs in sandwich boxes and snakes and lizards kept in under bed storage tubs for days at a time. It was a thing of beauty, a time which for many a generation has now been long forgotten. Yet for those who do remember it, they will be able to relive the thrill of catching your very own native snake, and that joy of keeping it. For some it was a matter of days, others whom were either lucky or subconsciously destined to be great keepers, they kept these as their own pets, opting for the more native approach over conforming to the generic beginner species stance. It was an utter joy to keep these snakes, by getting them to thrive in captivity, but the Holy Grail was getting them to breed.

Native UK Snakes and Venom

In the UK we only have three native species. The smooth snake Coronella austriaca is a very rare and highly protected snake confined to the South East of Dorset, South West Hampshire, and an area of East Hampshire and West Surrey. This means that it’s rather uncommon to ever see one and without a licence it’s illegal to even disturb one, let alone touch one. Adders Vipera berus on the other hand are very wide-spread over the UK, yet our own venomous snake. I should add that by venomous I do however mean front fanged snake with glands, without going into too much detail, Dr. Bryan Grieg Fry proved out in 2013 that in fact all snakes in the world, even so-called harmless constrictors do in fact contain venom, however it’s a redundant trait that now has no bearing factor over how it kills.

Normal phase adult grass snake

Courtesy of Christian Castille

In the case of the grass snake the mild toxins in its saliva are harmless to us, but do cause some effect on their prey which are primarily amphibians. There have been reports on the rare occasions where a grass snake has bitten a person, there was very mild tingling sensations in their skin but that’s all. Adders however, under UK law require a dangerous wild animals licence to keep them, just like all front fanged and some rear fanged species. This means that realistically the grass snake is the only option open to UK herpers whom are wishing to keep a native species of snake.

If we are to talk about non-native species then you can expand upon this, as we have 4 species of snakes which are known to survive and breed yearly. These are 2 colonies of Aesculapian snake Zamenis longissimus, one existing in London and another in Wales. A group of corn snakes in a remote part of Essex and then a mixture of Viperine snakes Natrix Maura and Dice snakes Natrix tessellata living in Cannock chase. Notice how I refer to them as non-native rather than invasive, this is because they do not actually pose a risk or offer a threat to the ecosystem they live in.

For many years I’ve been keeping and breeding native species in captivity. From slow worms to European hares, I’ve been fascinated in keeping and breeding animals which I share their land with. I keep, breed and work with all the exotic things too, but there’s something about native species you either get or you don’t. Far too often people look too far afield for interesting species and thus miss the ones right under their nose.

Captive Breeding of Grass Snakes

Now I’ve been breeding grass snakes for around 15 years and it’s a pure thrill to see the eggs begin to pip. There is often some confusion over the law of selling grass snakes. It is illegal to sell wild grass snakes, however captive bred ones are perfectly fine to sell, there is some bizarre rumour that they need to be third generation captive bred to be sold. This is nonsense as the law clearly states that as long as the specimen is not derived from the wild then it can be legally sold.

Natrix tessellata hatching

Courtesy of Christian Castille

I’m not a huge morph lover but I can appreciate them, I understand they’re the poster boy for our hobby and what has helped it to expand at such a massive rate. I do keep and breed morphs but I do prefer natural colours of pretty much all animals. This however has never stopped me from producing my own, such as the time I produced the first ever non polymorphic viper boa to be hypo, or the first albino ocellated skink and so on. As for grass snakes, I thought having morphs of them could be good because it might raise their profile a bit. In 2012 I purchased trio of het albino grass snakes from a Spanish breeder and then 5 months later brought a pair of het pieds from one of his contacts. These snakes are still maturing with me I was overjoyed just to consider being able to produce these in the future.

In May 2014 I had one of my female grass snakes lay a nice big clutch of eggs, consisting of 27 eggs. A good size for her, as previous years her clutches were less than 20. She laid for me every year and I always used the same male with her with no issues, always nice normal babies. She laid for me the week before I had a herping trip planned with some good friends of mine. So the following week we took the car out to one of my best locations for herping consisting of my fellow reptile breeder Ben Warden, Belgian hare breeder and photographer Sarah Fowler and conservationist Mike Potts.

Where we went out searching was a place only about 30 miles from my house, it’s fantastic to see wild deer and pheasants, it has an abundance of common lizards which is why it’s superb for finding adders because of their food source being in such accessible numbers. Grass snakes aren’t too common in the area we were but you do come across them now and then.

We must have been out in the field for about 2 hours, it was a very overcast day and only a few adders were out, a few nice big female common lizards were out attempting to bask. I imagine it was to try to warm up their bodies for all the live young they would be birthing within the next few weeks. We headed over to a large pool of water where I often seen red-eared sliders, of course these are not native as they’re indigenous to North America, however it’s a common sight to see these unwanted pets appear in places like this. Sarah was photographing a huge Stag eating fresh luscious leaves from a low hanging tree when all of a sudden Ben shouted


We all rushed over to see why such excitement was in his voice, as normally he would just use the snake hook. Mike ran over first to see that the snake had managed to escape Ben’s grasp and it slithered into a gap in one of the adders hibernaculums. Ben said he saw some sort of snake but didn’t know what it was as it was really bright! This got us all interested and we began searching until he hooked up a grass snake, a nice big healthy female, heavily gravid too, but this was not what Ben had seen. Moments later I saw the tail end of something resembling what Ben described, before I had chance to even announce it, Ben had been reacquainted with the snake again. He tailed it up off the heather mount with his hook. It began to musk over and over, squirting its foul smell over all of us.

Wild Caught Adult Hypomelanistic Grass Snake

Courtesy of Christian Castille

We sort of just all stood there gobsmacked scratching our heads at this snake, never in our lives had we ever seen such a snake, bearing in mind between the four of us we had over sixty years of herping experience. Sarah began to take photographs of this awesome animal; we all agreed it was a hypo grass snake, which I knew for a fact was the first anyone had ever seen, as only one week before this on one of the natrix discussion groups we were talking about phases, morphs and geographical differences in them. To find your very own morph of wild snake that you’re a huge fan of is an amazing experience. We then all had a hold of this beautiful animal, appreciated it for what it is, then released it back into the wild. Herping for us is about studying and getting up close to these animals, not about being a kid in a candy store and taking pick of whatever freebies we want.

I announced my findings on Facebook and other internet media I use, to which I had an overwhelming amount of interest, including people asking where I discovered the animal, which of course I refused to say. Yet the best part of this story was some seven weeks later after finding this snake,the previously mentioned batch of grass snake eggs began to pip. Nothing too unusual about that, I was incubating them on vermiculite and rotten leaf litter at 29c so I expected them to hatch around this time, in all it took three days from start to finish for them to leave the eggs. The first three came out no problem, lovely normal grass snakes. The fourth one however had a very light head, I joked with Ben and said imagine if it’s a hypo. He laughed and said I sadly wasn’t that lucky. The following morning I nearly had a heart attack when I saw three more normal sat on top of by four hypo grass snakes. More and more began to hatch, in the end I got twelve hypo grass snakes, ten normal grass snakes, two infertile eggs and three stillborn.

One of the stillborn was a very deformed hypo with no eyes and severely underdeveloped. However on the plus side, not only had I produced the first ever hypos, but it seemed to be two strains of them, seven of them were very pale, whereas the other five of them were darker yet all still lacked any green on them which is what you would expect as the uniformed standard for them.

I gave a few of them to my friend Ben to work with while I kept the rest back myself. I’ve had some people suggest how it was very odd that I stumbled upon a hypo, then seven weeks later hatched out my own, however I do have a perfect time scale to back up all breeding within this project. As to date I’ve had offers of as much as £2,500 each for these hypo grass snakes, yet I have no plans on selling them as I wish to work with this project in order to see if I can define the traits of them and raise the awareness of natrix as pets. My plan is also to breed from these babies with the intention of producing more hypos. If it turns out profitable, I’d like some of the money to be donated towards helping our own native herptofauna as in the UK it’s really taken a beating over the last 20 years.

Hatchling Hypomelanistic Grass Snake

Courtesy of Christian Castille

Currently these hypo’s have been taking chopped up trout fillets and recently moved onto pinkie parts. They are now being conditioned for brumation and will remain this way until around the beginning of March. I can’t tell you how amazing it is not only to discover a morph in the wild, but to then replicate it in captivity. I think this is something most herpers dream of and I hope this little project works out as I’d love to do a follow-up article in a few years’ time showing the second generation of hypo grass snakes.