San Francisco Garters in Europe - family tree?

[Conners]

Hi there,

I'm new to the site (although I've kept and bred snakes since I was a kid in the 80s).

I have been wondering if any efforts have been made to track the relationships between T.s.tetrataenia in captivity?

I have an 08 pair that I bought from a very responsible breeder who sourced them from The Netherlands. However, he doesn't known, for example, which captive group they are descended from (Jersey zoo? ZSL? Private breeders in the Uk/Europe?) or if they're a filial generation.

I think those of us keeping and breeding these special snakes have a responsibility to do the best we can with the bloodlines we've got to keep the captive population healthy and genetically diverse.

As many of you know, there is very little habitat left for these guys in San Mateo county. So although it's unlikely that our animals will ever be called upon to replenish the wild stock, if tetrataenia reaches the edge of extinction in the wild the captive bred animals will become important to conversationists.

People interested enough in garter snakes to seek out and pay the premium for tetrataenias will often frequent sites like this. In which case, it might be possible for us to get together a register of captive snakes?

That way we can track relationships between them going forward, allowing breeders to avoid producing heavily inbred animals. For example, a decade from now we can cherry pick animals that last shared an ancestor 4-5 generations back, and arrange swaps to keep the genepool as healthy as possible. I know that the European snakes are inbred as it is, but a lot of endangered animals have been through population bottlenecks that reduce the species to an handful of animals, and this still provides enough genetic diversity to restart a viable population.

If we were properly organised we'd be more likely to get taken seriously by those with the power to talk to the Californian authorities and maybe even look at refreshing the stock every ten years or so with a couple of wild caught snakes. I've got a couple of contacts at ZSL so perhaps we could involve them down the line (London Zoo breed SF garters).

What do you guys think? Do you know if anyone has tried anything like this before for this subspecies or any other threatended snake? There would be very little overhead involved in setting it up and the information would be so useful. I'd be happy to create a website if there was enough interest - or perhaps we could run it through here?

Maybe some of you guys are way ahead of me with this - anyone know?

Cheers

Conners

[adamanteus]

Hi Paul, and welcome to the forum.:)
It is my belief that all the tetrataenia in Europe are decended from the one, single group that was originally held by Jersey Zoo. Although over the years they have 'done the rounds' a fair bit. I saw a trio in Edinburgh Zoo in the early 90s, which had come from Jersey.
I don't think anyone has made much effort to separate the breeding lines out.... but I guess it's never too late to start! I'd certainly be interested in being involved.... although I can trace the lineage of my tetras only a few generations.
I'm guessing that despite the flag, you're not in the US?:D

[Stefan-A]

Welcome aboard, Paul. :)

I wish I could help, but I can only trace mine back to the previous owner and I'm unsure about the breeder. However, I highly doubt that the captive population will be of any use in a reintroduction programme, especially since the problem isn't that there are too few of them in the wild.


I don't know if you'll find this link useful, but here it is anyway: http://www.thamnophis.com/archive/articles/artic3.htm

A small excerpt from the article:

As we have explained the total number of specimens of Thamnophis sirtalis tetrataenia in Europe are offsprings of the animals introduced to Jersey. This parietal generation of all San Francisco Garter Snakes in Europe was surely inbred, because it is possible that they all came from the Zoo in Memphis (USA) where only one pair of San Francisco Garter Snakes was kept for a long time (WEISS-GEISSLER & GEISSLER, 1995).

[reptile3]

Hello Paul & Welcome:)

[guidofatherof5]

Welcome to the forum, Paul

[infernalis]

Welcome to the forum Paul.

Very interesting idea:D

[Conners]

Hi guys,

Thanks for the welcome and for the encouraging responses and info.

I'll check out the link you recommend now. I'm certainly very interested in finding out anything that's already known about the lineage going back to the Jersey animals.

As you rightly guessed I'm not in the US (I'm in London) - must change the flag thing!

Paul

[adamanteus]

It's always nice to welcome a fellow Brit, Paul.
Can you trace the lineage of your tetras very far?
I think it's a great idea that we keep future breedings as 'unrelated' as possible.... but it will be difficult to get some people on board.
I'm up for it though. I think part of the problem is the surfeit of males..... I have a trio, one of which is female.:D They were already attempting to mate prior to brumation, so I'm hoping for a fruitful year..... but I'd be quite happy to exchange one of my males for a more distantly related male, if that can be figured out.

[adamanteus]

I think part of the problem is the surfeit of males......


Which makes me think....... Many of you may already be aware of 'temperature dependant sex determination' in the incubation of reptile eggs (keep them warmer = more males, keep them cooler = more females), this works for live bearing snakes too. I needed more radix females so I kept my gravid female cooler than I might have otherwise..... out of 18 young she had 17 females.
I wonder if breeders have tried this with tetrataenia... I know I will next year.

[infernalis]

Which makes me think....... Many of you may already be aware of 'temperature dependent sex determination' in the incubation of reptile eggs (keep them warmer = more males, keep them cooler = more females), this works for live bearing snakes too. I needed more radix females so I kept my gravid female cooler than I might have otherwise..... out of 18 young she had 17 females.
I wonder if breeders have tried this with tetrataenia... I know I will next year.

Thank you, Cheers, Salutations:D

James that little tidbit of info just made my whole day.

It also explains something, while my gravid eastern was gestating, I provided her with a hot rock (set on low) that she chose to sit on nearly all the time, I wound up with a litter of nearly all males.:(

[Snake lover 3-25]

ooooo wow so that's why i got 13 females and 2 males from sooty!!! RIP babies......:(

[aSnakeLovinBabe]

weird.... I've never really noticed a trend like that before... all my litters have been pretty even and I keep my females very warm during gestation.


having said that, I think all of this stuff is a good idea, except for the part of removing a few SF garter snakes from the wild every few years to replenish captive populations. I don't think that any more should be removed from the wild. The ones that are being squished on the roads are losses enough.

Having said THAT.... I truly believe the SF garter is doomed.:(

[Conners]

Hi guys,

I read the Chlebowy & Martin Hallmen article - very interesting; the first detailed info I've come across on someone's efforts to tot up the European population. Cheers for the link Stefan.

I'm not sure when it was originally written, but I'm guessing a little while back, as the figures for the captive population will surely have risen since? If I was asked to guess, based on how often animals are offered for sale on sites like reptileforums.co.uk, I'd say there must be at least a few hundred SF garters in the UK and Ireland alone.

If they really are all descended from the original pair which were themselves inbred, we could easily be on something like an F15 generation.

Mine seem very healthy and are growing like weeds on a pink diet, but there's no knowing what deleterious genetic traits they're hiding. I don't known anything about their background beyond that there were born in Holland, but I am planning to pair them. What I want to do if I get a healthy litter is see if my contact can persuade Ian who takes care of the London Zoo animals (and breeds his own) to do a couple of like-for-like swaps.

It's very interesting what Adamanteus said about the surfeit of males. I actually came up against the opposite problem when trying to source a pair. I didn't see the point in taking any tetras off the breeder unless he could give me one of each sex, but he only had a single spare male as against half a dozen or so females, so it may be that the gravid female in question was exposed to high temperatures during gestation. I must admit I wasn't aware of how definitive that was in breeding garters, so cheers for the info guys. Thinking back to when I used to breed parietalis, I always had a thermal gradient available, so I never noticed any imbalance of the sexes in the litters.

Has anyone come across examples of inbreeding problems in tetras? For all I know, half the snakes in every litter might be being born with spinal kinks. On the other hand, maybe no issues have shown up?

From what Vince Russo and other big breeders in the US have discovered from pretty extensive experiments, it seems safe to line breed for at least 6 or 7 generations before you can expect to see any issues. After this however, all bets are off.

[Conners]

It's always nice to welcome a fellow Brit, Paul.
Can you trace the lineage of your tetras very far?
I think it's a great idea that we keep future breedings as 'unrelated' as possible.... but it will be difficult to get some people on board.
I'm up for it though. I think part of the problem is the surfeit of males..... I have a trio, one of which is female.:D They were already attempting to mate prior to brumation, so I'm hoping for a fruitful year..... but I'd be quite happy to exchange one of my males for a more distantly related male, if that can be figured out.

Cheers for the encouraging words Adamanteus. I guess the problem with my idea of a register of animals is that the meaningful data doesn't come through for a few years, because we start with a list of animals whose relationships aren't known. So it will take time and patience. I do think it would be worth it though. Within just a couple of years we'd have broken the chain of filial generations and could be mating cousin snakes instead of siblings.

I don't know anything about the lineage of my two I'm afraid - quite frustrating, but the chap who who sold them to me didn't ask the Dutch breeder at the time of purchase. He's offered to try and find out more though.

Good luck breeding your guys post brumation!

[adamanteus]

I don't know anything about the lineage of my two I'm afraid - quite frustrating, but the chap who who sold them to me didn't ask the Dutch breeder at the time of purchase.

To be honest, Paul, there's every chance that the original breeder of your tetrataenia is a Thamnophis.com member. We have some of the biggest European Garter keepers on this forum, including some 'leading' Dutch keepers.

[Conners]

To be honest, Paul, there's every chance that the original breeder of your tetrataenia is a Thamnophis.com member. We have some of the biggest European Garter keepers on this forum, including some 'leading' Dutch keepers.

Cool - fingers crossed that will be the case! I'm sure some of those guys must already be doing what I'm proposing in terms of the register. I mean if they've bred SFs a few times I'm sure they themselves will be trying to keep the genes as mixed up as possible. I really hope we hear from someone about it if that's the case.

Cheers James!

Paul

[adamanteus]

Certainly mine came with breeding documents and 'ID numbers' (eg. tst 3-0 "Rotterdam Line"). They are from a Dutch breeder (Gijs & Sabine).