The herpetocultural literature on the raising of young garter snakes is surprisingly scant. Apart from some issues of diet, the care of adult garter snakes is little different from that of any other medium-sized North American colubrid. Books on the subject either deal with neonate garter snake care in very general terms, or treat it as similar to that of other snakes. But this is not the case. There are some definite differences in the care of newborn garter snakes, especially in terms of feeding and housing. As a result, when my garter snakes started breeding in the spring of 2001, I was not prepared for some of the surprises their offspring had in store for me.
What I propose to do in this article is to share what I’ve learned from raising a few litters1 of garter snakes, plus a few neonates that I did not breed, but acquired when they were very young. This is by no means scientific or definitive, but anecdotal. It’s merely what I’ve observed. If your observations differ, by all means share them: at this point, we need as many observations as we can get, if we’re to understand better how to look after our charges.
I’d like to begin with a few observations about breeding, which is obviously the necessary first step. In my limited experience, I have not found garter snake breeding to be at all difficult: every attempt at pairing has been successful. All I’ve done is either keep the breeding pair in the same cage at all times, in the case of my pair of Red-sided Garter Snakes, Thamnophis sirtalis parietalis, or introduce them in the standard manner for colubrids, in the case of my pair of Wandering Garter Snakes, Thamnophis elegans vagrans, which I kept separately for fear of ophiophagy (which is well documented for that taxon).
Nevertheless, breeding was far from routine. My male T. s. parietalis was resolutely indifferent to mating season. When I first introduced him to the female in mid-October 2000, he pounced immediately. Intromission occurred after two weeks of intense and dramatic courtship; courting behavior was observed for weeks thereafter, and he refused food for nearly two months. They were artificially brumated over winter, at temperatures between 12 and 15°C. The following March, I introduced him to a second female T. s. parietalis owned by a friend. They were in the cage together for only a few hours; mating this time was immediate. Both females gave birth in late May.
The following July, entirely out of season, he mated with my female again. She did not give birth until June 13, 2002, when she delivered a litter of 42 babies — a total of eleven months between mating and birth, four of which were spent in hibernation. Clearly, female garter snakes are more than capable of retaining sperm until ovulation. From what I’ve been able to observe, female garter snakes ovulate almost immediately after coming out of hibernation, and give birth approximately two and a half months after conception: my T. s. parietalis gave birth a month later in 2002 than she had in 2001, but she had also come out of hibernation a month later. Similarly, my female T. e. vagrans, which had mated in mid-April 2002, delivered seven babies on July 3, 2002.
The birth process itself takes very little time. I was able to witness — and photograph! — the birth of my 2002 litter of 42 T. s. parietalis, which took less than a couple of hours. The babies emerge from their birth sacs within minutes, some more quickly than others: at least one baby was breaking out of its sac before the sac had finished emerging from the mother!2
The babies’ first shed occurs almost immediately. The skin is extremely thin and ephemeral compared with that of other colubrids, and can easily be lost in the general mess and snake traffic that occurs during birth. This contradicts Perlowin (1992), who writes that garter snakes shed seven to 10 days after birth, like other snakes. Because my first litter of T. s. parietalis, in 2001, was born when I was away doing field and conservation work on Pelee Island, I wasn’t able to observe the immediate shedding, and assumed, based on what I had read, that the snakes would shed after a week or two. I ended up waiting for weeks for a first shed that had already taken place, when I should have been trying to feed them.
I’ve had considerable trouble getting baby garter snakes to feed. Part of this may be due to retained yolk. From what I’ve seen from my own litters and those of friends, T. sirtalis tends to have large litters of small babies, whereas other species — in my case, T. e. vagrans and T. sauritus septentrionalis — seem to have smaller litters, but the babies are larger. My T. e. vagrans babies in particular appeared to have considerable yolk reserves and were in no hurry to begin eating.
On the other hand, they may have had some difficulty recognizing that what I was offering was food. At the outset, the easiest food items for me to offer were chopped nightcrawler, Lumbricus terrestris, and pieces of ocean perch fillet, Sebastes marinus. Neither was accepted with any regularity, which suggested that the snakes preferred food items that moved: fish fillet was obviously non-ambulatory, and the nightcrawlers were so large that pieces cut small enough to feed to the snakes were too small to even twitch.
In an urban environment, finding appropriate food items was problematic. Smaller earthworms were usually accepted with relish, but without a garden they were hard to acquire. I took to carrying plastic containers with me on my walks to and from work when it rained, so that I could collect worms from the roads and sidewalks, and asking friends to send me their garden denizens. Live fish were also accepted, but they were expensive, difficult to acquire in bulk, and required long bus trips to buy them, since neither I nor my partner at the time owned a car.
The other issue was simply one of quantity. Fifty baby garter snakes can eat a copious amount, particularly if they’re eating platies and earthworms. A single snake can eat several fish or worms. Multiply that by fifty, and then two or three times per week, and the supply issue becomes monstrous. It was difficult and time-consuming to provide enough, and in many cases we simply couldn’t. Eventually, they grew large enough to take nightcrawler pieces, which simplified things, but I lost quite a few in 2002 before they got to that stage, simply because I couldn’t provide them with enough nourishment.3
A more serious setback came in the form of internal parasites: tapeworms or roundworms. A single bad batch of feeder fish bought from a pet store in late 2001, I now believe, had a devastating impact on my natricine collection, though I didn’t recognize it at the time. Many snakes ended up with a tapeworm infestation in their lungs that eventually killed them. I want to emphasize eventually, because snakes were dying from this a full two years later, and were frequently in apparently good health until I found them suddenly upside-down one morning. Several of the babies I had been raising succumbed; I ended up offering free replacements to customers who had bought snakes that subsequently, and inexplicably, died.
My original strategy had been to feed them worms and fish until they were large enough to take pinky mice or pinky parts. This was both labour intensive and riskier to the snakes’ health than I was comfortable with. And, as I’ve said, some baby garters were not enthusiastic about their traditional diets. Ironically, several of my T. e. vagrans babies were finicky eaters until they were converted to mice, at which point they fed voraciously.
So, when I acquired a couple of neonate Eastern Garter Snakes, T. s. sirtalis, in late 2002, I tried something different: rather than waiting until the point where I would normally convert them to pinkies, I tried pinky parts — unscented — immediately. To my great surprise, it worked: they ate without hesitation. This repeated itself the following year, when I acquired two Checkered Garter Snakes, T. m. marcianus, that were so small that they could not have been more than a month old. Again, I tried very small mouse parts, which they ate. No scenting was required.
Not every garter snake can be converted to a mouse diet, but I began to think that for those that could be converted, it could happen at a much earlier age. Doing so might address both the initial reluctance to feed and the difficulties in providing them with enough food so that they could grow properly.
Denise Loving, having listened to me talk about this, tried this for herself with her litter of nine Blue-striped Garter Snakes, T. sirtalis similis, born in July 2004. From the outset she offered them both worms and pinky parts. Within two weeks, she reported that seven of them were eating lightly scented pinky parts (pers. comm.). Compared to the lack of success I’d had in 2001 and 2002 at that stage, this was quite encouraging. Unfortunately, I don’t have any breedable pairs of garter snakes at the moment, so it will be a while before I can test this hypothesis again.
I’m a strong advocate of converting garter snakes to a mouse-based diet generally (Crowe 2000; Crowe and Hathaway 2000), but it appears to be especially useful for rearing young garters in captivity. The 2002 litters suffered no mortalities after they were converted to mice in October of that year: any that occurred happened before that time. Similarly, I haven’t lost a single garter snake baby since that I had started on a mouse diet. I think that the benefits, in terms of greater nourishment per feeding and a parasite-free food source, are obvious.
Having spent so much time on feeding, I should say a word or two about housing. For ease of cleaning, I use paper towelling as substrate: it should come as no surprise to garter snake keepers that several babies, housed together, can rapidly foul their cages. My caging for young garters is otherwise the same as for other colubrids, with one exception. Small snakes seem especially prone to dessication: this applies to adults of small species (e.g. Storeria) as much as neonate garter snakes. I lost five young garter snakes during a heat wave in the summer of 2001; since then, I’ve made a point of providing young garters’ cages with a humidity gradient, which can be as simple as a patch of moistened sphagnum moss or, more elaborately, a humidity box. It’s a useful precaution if your home’s temperatures soar into the mid-thirties Celsius.
The general consensus seems to be to house them together, rather than separately. Philippe Blais does so, and finds that garter snakes housed in such a manner are calmer than they would be if housed separately (pers. comm.; Blais and Crowe 2000; but cf. Rossi and Rossi 2003). My own observations confirm this: garter snakes housed individually tend to be more nervous and whippier than those housed in groups. It seems a natural thing to do, given Thamnophis’s tendency to aggregate in the wild, but there are some caveats to be aware of.
With some snakes, of course, their cannibalistic tendencies require separate housing: as a precaution, I keep Wandering and Checkered Garters one to a cage. Also, I don’t mix species or subspecies. On the other hand, I’ve kept as many as 10 or 11 neonates in a cage 40 cm × 20 cm, and 24 neonates in a cage 60 cm × 30 cm, without incident. Fortunately, as they grew, I was able to sell a few of them and as a result keep fewer per cage; I don’t know what I would have done if I hadn’t sold any of them!
One drawback to housing them collectively is that it becomes more difficult to monitor their food intake. Hungry natricines, as a rule, do not ration themselves, and the more aggressive feeders will leave none for the others: 30 fish fed to 30 snakes may end up in the stomachs of only a few. Unless you’re able to tell by sight which snake is which (an unlikely prospect in most cases), it’s impossible under such circumstances to tell who’s eating and who isn’t. The second issue is one of food fights, where two snakes try to grab the same food item. Some snakes are sensible enough to let go before they’re swallowed by a sibling, but it does happen, and separating two (or more!) snakes who’ve attacked the same fish or piece of worm can be a challenging — and stressful! — experience.
Housing them collectively, but feeding them individually, is therefore the best option. My partner and I use plastic food containers, and we’ve gotten quite efficient at it. Once the snakes learn that being put into a deli container means that they’re being fed, it’s usually not difficult to coax them inside. With a bit of practice, feeding even a large number of baby garter snakes can become a matter of routine.
First published in The Garter Snake (April 2005).
- Three litters of Red-sided Garter Snakes, Thamnophis sirtalis parietalis, two in 2001 (N = 26, 24) and one in 2002 (N = 42); one litter of Northern Ribbon Snakes, Thamnophis sauritus septentrionalis (N = 9); and one litter of Wandering Garter Snakes, Thamnophis elegans vagrans (N = 7).
- View the photographs of this birth online.
- The Northern Ribbon Snakes were not offered nightcrawlers.
Blais, Philippe and Jonathan Crowe. 2000. The San Francisco Garter Snake in Canada. The Ontario Herpetological Society News 87.
Crowe, Jonathan. 2000. Understanding Garter Snakes Through Their Diets. Chorus: Newsletter of the Ottawa Amphibian and Reptile Association 17(8).
Crowe, Jonathan and Jeff Hathaway. 2001. Domestic Mice as Food for Butler’s Garter Snakes, Thamnophis butleri. The Ontario Herpetological Society News 88.
Perlowin, David. 1992. The General Care and Maintenance of Garter Snakes and Water Snakes. Lakeside CA: Advanced Vivarium Systems.
Rossi, John V. and Roxanne Rossi. 2003. Snakes of the United States and Canada: Natural History and Care in Captivity. Malabar, Fla.: Krieger.
Rossman, Douglas A., Neil B. Ford and Richard A. Siegel. 1996. The Garter Snakes: Evolution and Ecology. Norman OK and London: University of Oklahoma Press.