Captive Care and Husbandry of Indigos and Cribos
Whether you intend to breed your snakes or keep them as pets, careful consideration must be given when making your choice. The Drymarchon genus can be an extremely rewarding group of animals to be working with, but like any other captive animal, they have specific care requirements that must be adhered to in order to ensure the health and happiness of the animal.
The first choice a prospective drymarchon owner will be faced with is which type of snake works for you. All indigos and cribos are similar in most ways, but a future owner must consider the slight variations in the personalities and the captive care requirements that are inherent in each of the species/subspecies. Factors to consider are: price, appearance, temperament, and captive care requirements.
Eastern indigos have a reputation of being the pinnacle of the drymarchon snakes. They are renown for their gentle nature, and their intelligence. My experiences with them have further supported this reputation. They are seldomly aggressive towards their keepers and, provided proper care is given, they are a hardy species and do very well in captivity. They are jet black and many specimens have red throats- a trait that many breeders attempt to maximize.
Because Eastern indigos are a protected species, one must obtain a Federal Interstate Commerce permit to transport them over state lines. The permit costs $100 and it generally takes a couple months to be issued. Although the process is much easier than most people think, many people choose to buy from in-state breeders to avoid this process. If it is your intention to breed Eastern indigos, their level of protection is something to consider. It is nearly impossible to legally ship them internationally, and, as mentioned above, many buyers will avoid purchasing from out-of-state breeders. This can somewhat limit your market. However, Eastern indigos still fetch a higher price than most other drymarchon.
Texas indigos are similar in appearance to the Eastern indigos. Although they can be variable when one considers the expanse of their natural range from Texas down the east coast of Mexico, they tend to be black like the Easterns with a brownish chin. Generally speaking, they tend to be a bit more high-strung than the Easterns, but can be just as hardy in captivity and just as rewarding. They are fairly comparable to the Easterns in price, if not a bit cheaper, but they are not federally protected. You can buy or sell captive bred specimens internationally and domestically without restriction (excluding Texas). Baby Texas indigos also tend to be a bit less finicky around feeding time than the other drymarchon.
Mexican Redtail Cribos
As of now, Mexican redtails are the most seldomly offered drymarchon in the US pet trade with the exception of Drymarchon orizabensis, Drymarchon melanurus caudomaculatus, and Drymarchon margaritae. Their natural range covers a large part of Mexico, and there is some variation in their appearance. They are as large and robust as the Eastern indigos- perhaps even more so. They are generally black animals with a creamy white throat. There are also a few specimens in US collections that have a somewhat mottled pattern. These are truly impressive animals and are commanding a very high price- perhaps even higher than the Eastern indigos.
Blacktail and Unicolor Cribos
Blacktail and Unicolor Cribos can be extremely similar in appearance, personality and in care requirements. Most people view a “classic” blacktail as a tannish animal with a jet-black tail. Likewise, most people view a “classic” unicolor as a solid tan animal without the black tail. However, within their respective ranges, blacktails and unicolors can vary tremendously in appearance. Snakes from the heart of blacktail range can have a brownish tail or be unicolored in appearance. Likewise, snakes from unicolor range can have black tails. In fact, many people speculate that blacktail cribos and unicolor cribos should be taxonomically considered the same animal with a lot of natural variation.
Many animals in the US pet trade have brown tails and don’t fit into most people’s minds as a “classic” blacktail or a “classic” unicolor, but some sort of an undesirable intermediate. Their beauty is in the eye of the beholder. Some insist on the classic look, while others are content with the browntailed look as it is also a naturally occurring look in wild caught animals.
When researching which blacktail or unicolor cribos to purchase, remember that babies will change in appearance as they age. One can never be certain if a baby will have a black, brown, or unicolored tail as an adult. The best advice is to ask to see photos of the parents. Although there will still be variation within a single clutch, babies will generally tend to look like their parents.
Blacktails are currently easier to find in the pet trade and are the most inexpensive drymarchon out there. Although they are generally more active and skittish than the indigos mentioned above, mine rarely, if ever, have tried to bite me. Despite their modest market value, blacktail cribos are my personal favorite of all the drymarchon.
Yellowtail Cribos are the longest of the Drymarchon genus and have been recorded at lengths of over ten feet. They have a more slender build, and on average, tend to be the most aggressive of all drymarchon. They have an extremely large range throughout most of South America and their appearance can be highly variable. Wild caught imports are commonly available in the United States and are generally cheaper that captive bred specimens. Most breeders try to accentuate the brightness and the amount of yellow in the snake. People tend to look for a bright yellow head and for the yellow on the tail to extend up towards the midsection of the body.
Wild Caught Imports
As one continues to research which drymarchon would be the most appropriate investment, the next decision would be whether to purchase a wild caught or captive bred animal. This decision is a non-issue with the Eastern and Texas indigos. It is illegal to collect either of these snakes from the wild, and barring black market offerings, all the snakes offered in the pet trade are captive bred. It will also be highly unlikely to find a wild caught Mexican Redtail Cribo being offered as Mexico stringently prohibits the exportation of wild caught animals.
However, yellowtails, blacktails, and unicolors are imported into the US on a fairly regular basis. Many people are tempted to purchase a wild caught cribo because they are cheaper, and adults are more readily available. However, these advantages are offset by a few serious concerns. Wild caught cribos are often heavily parasitized and will require treatment upon acquisition. If you choose to purchase a wild-caught animal, count on having your animal treated for internal and external parasites- preferably by an experienced reptile veterinarian. The import should also be fully quarantined from the rest of your collection until its health can be completely stabilized.
One of the frequent concerns over working with wild caught reptiles is the uncertainty over what type of care the animal has been receiving prior to your acquisition. There can often be a significant amount of time between when the animal was captured and the time you acquire it. As will be discussed below, indigos and cribos can be extremely sensitive to dehydration, and if an animal is kept without water for a period of time, long-term health problems can develop as a consequence. Wild caught cribos are often severely dehydrated as well as parasitized upon importation into the US.
An import’s dietary preferences can also be a concern. As will also be discussed below, drymarchon consume a wide variety of prey items in the wild. An import may be accustomed to eating birds, fish, frogs, snakes, or any number of other things in the wild. It can often take a lot of time and patience to get an import feeding consistently on rodents.
In my opinion, the lower cost of imports is more than offset by the concerns they present. I am rarely tempted to spend money on imports unless it’s a color variation that is not readily available in the pet trade.
Captive Bred Animals
If you choose to purchase a captive bred animal, your next decision is to select a breeder. When choosing a breeder, there are several factors to consider. When one chooses to purchase a captive bred animal, it is with the assumption that the animal will be of better health than an import. In my experience, there are breeders with whom I am confident in dealing with, and there are others with whom I am not. Ask for references. Ask for recommendations from others in the reptile community. A good breeder should provide a healthy animal, be willing to share husbandry tips to further ensure the long-term health of the animals they produce, and make things right within reason if a buyer is unhappy with a purchase.
Once you’ve researched the various drymarchon species/subspecies, and you’ve decided upon an animal, your next step is to make certain you are providing your new purchase with the captive care it needs to be a happy and health.
On average, indigos and cribos are active, diurnal snakes that need some room to roam. Most keepers recommend 6’ x 2’ cages as the minimum size to house a full-grown adult drymarchon. The need for space is not quite as dire your young snakes as they spend much of their time hiding- presumably out of their natural instinct to fear potential predation. I find that shoeboxes are sufficient for hatchlings. Once the animals are approximately six months of age, I move them to enclosures that are approximately 2’ x 1.5’. Once they surpass 3’ in length, I move them into a cb-70 rack until they are large enough for their adult enclosures.
As with most reptiles, a thermal gradient is recommended for indigos and cribos. Allowing the snakes to thermoregulate themselves most accurately mimics their natural behavior in the wild; the trick is to provide the correct temperatures at both ends of the cage. Drymarchon are very sensitive to high temperatures, and novice keepers often accidentally kill snakes by mismanaging cage temps. Ambient temps in the snake room should be kept between 70-78 degrees as the temps naturally fluctuate with the seasons. Temps on the cool side of the cage should never exceed the low 80’s. Excessive heat can cause the snake to rub its nose completely off, and can also cause death. Precautions should be taken to ensure summertime temps never cause the ambient temps in the snake room to get too high. When a snake is kept too cool, it can get sick, but when it is kept too hot, it can die within minutes!
Once a stable room temp is provided, a hot spot should be given on one side of the care that can be in the mid 80’s. Just be certain to offer the snake plenty of space and a hide box on the cool side of the cage. Temperature drops to stimulate breeding will be discussed below.
Drymarchon, particularly the Central and South American cribos, need to have some amount of humidity in their cage. Some keepers provide this humidity by providing a substrate that holds moisture well like peat moss and misting it daily. Others, myself included, prefer to provide a humid hide box in the cage that is filled with slightly damp spaghum moss. The snakes will use this humid hide, particularly as they prepare to enter their shedding cycle. A properly hydrated snake will be much less likely to retain eye caps and tail tips while shedding. Humidity can also be raised with a wide, and shallow water dish.
Whether it’s an Eastern indigo from Florida, or a yellowtail cribo from Argentina, most drymarchon live in areas that experience heavy seasonal fluctuations in humidity and rainfall. Many keepers mist their cages to mimic these seasonal changes. Proper caution should be taken to prevent oversaturating the substrate. As a general rule of thumb, the moisture from the misting should dry out over night to avoid the risk of mold or mildew growing in the cage.
One of the primary reservations people have about keeping indigos and cribos is their defecations. Drymarchon are notorious for having fast metabolisms with frequent and foul-smelling defecations. Drymarchon breeders are constantly on the hunt for substrates that contain the odor and help to maintain a clean environment for the snakes. Chief concerns are: making certain the substrate is not large enough to cause impactions if ingested, odor control, and humidity retention. Many use newspaper and have resigned themselves to frequent cage cleanings. Others opt for highly absorbent substrates like CelSorb or Stable Blend pellets which hopefully allow them to not have to clean after every defecation. The problem with these absorbent substrates is that they can remove some of the humidity from the cage. This can be counteracted with misting and a humid hide box. There’s no right or wrong answer here- it’s just a matter of finding a substrate that works for you.
No matter what substrate you choose to use, the reality is that drymarchon keepers probably end up cleaning cages more often than most other keepers. If this is a bother for you, then perhaps and indigo or a cribo is not the right choice for you. A clean cage is essential for any reptile’s overall health. I spot clean my cages 1-2 times a week, and I deep clean them once every month or so. A diluted bleach solution or Nolvasan (Chlorhexidine) should be used to kill any bacteria during deep cleanings
Indigos and Cribos drink relatively high volumes of water and the need to provide them with a steady supply of fresh, clean drinking water is much higher than it is for most other reptiles. As mentioned above, drymarchon are extremely sensitive to dehydration, and a lack of clean drinking water, even for a few days, can lead to serious health problems.
Many keepers use water dishes that are large enough for the snake to soak in, however, I choose to provide smaller water dishes that do not tip easily and I have never had a problem. Their water should never run out, and should always be kept clean and fresh. Water dishes should be cleaned and sterilized frequently to prevent the accumulation of bacteria, fungi, or parasites.
Indigos and cribos are generally very aggressive feeders. They are not constrictors and are adapted to crush and devour their prey in their extremely powerful jaws. Although many keepers successfully keep their drymarchon on a rodent-only diet, I am a firm believer that the snakes are happier and healthier with a varied diet. In the wild, these guys will eat just about anything they can overpower. Other snakes, lizards, birds, fish, frogs, rodents… anything is game! As such, I feed my snakes chicks, chicken necks, quail, fish, rats, mice, and other snakes. All are frozen thawed and are proportionally small. I keep the meal sizes small for a few reasons. First, their jaws do not open as wide as other snakes. Even an eight-foot indigo can’t handle a jumbo rat. Large meals can also cause some adults to lie around and get obese. I believe the animals do well with smaller, more frequent meals. I feed them small/medium-sized meals twice a week.
The appetite of some adult drymarchon can fluctuate seasonally. Shorter days and cooler nights often cause my adults to lose their appetites for a period of time. This is perfectly normal. They should start eating more consistently when springtime rolls around. My snakes’ appetites are always in full swing during the warmer summer months. A keeper should always be extremely cautious when opening cages around feeding time. It is not uncommon for an indigo or cribo to lunge out of a cage with a gaping mouth. These are extremely powerful animals with jaws like vice grips. If bitten, expect severe lacerations and a lot of blood. Be on your toes and extremely cautious during feeding time!
Once your snakes are around the six-foot mark, you can start considering breeding. Egg binding can become a significant risk if you attempt to breed females that are too young. Most breeders recommend the females to be four-years-old and about six-feet long.
As mentioned above, in the fall, some of your adults will start becoming less interested in food. At which time, you’ll want to start cooling them down. For Eastern and Texas indigos, reduce their nighttime temps slowly each night until you’re reaching drops of about 60 degrees. For the other cribos, I generally keep the nighttime drops about 68-70 degrees. I will also lower the temps of their hot spot during the day down to 80 degrees or so.
Once the appropriate temps are achieved, your males will often refuse food altogether and start frantically searching their cage for a breedable female. This situation should be closely observed as males will sometimes rub their noses raw searching for a female. Once pairs are introduced under these conditions, breeding generally begins immediately. The snakes should be observed closely as the males can sometimes become aggressive towards the females and their bites can cause deep lacerations. Actual copulation can last several hours. Pairs should be separated once copulation ends. I like to reintroduce the pairs several times during the breeding season to ensure success. I stop putting them together once they lose interest in each other and remain on opposite ends of the cage. If the matings were successful, the female will become very fat and become less active. At this point, I slowly start returning the hot spots in the cages back to normal, so the female can warm her gravid body. Three or four months after breeding, the female will often refuse food, become more active, and go through her pre-lay shedding cycle. A nest box with damp spaghum moss should be in the cage to provide her with a place to deposit her eggs. Once you get good eggs, half the battle is over, and it becomes time to think about correctly incubating the eggs to ensure happy and healthy babies!
As with the incubation of all reptile eggs, there are two primary considerations: temperature, and humidity. Drymarchon breeders use a variety of substrates to help the eggs maintain the right hydration levels. Some use vermiculite, while others use perlite, and others still use sand/spaghum. I personally use vermiculite. I keep about four inches of very slightly damp vermiculite at the bottom of the egg container, and then I put 2 inches of dry vermiculite on top of that. This keeps the eggs moist, but by keeping them from being in direct contact with the damp vermiculite, the risk of mold development in minimized. The eggs will have a rough, granulated texture in contrast to the smooth, leathery feel of most other snake eggs. The eggs should not be moved, or rotated once set in the incubator. Drymarchon eggs need to be kept less humid than other colubrid eggs. They can be prone to swelling as they absorb extra water through their semi-permeable shells. If left unchecked, eggs can burst under the pressure.
As for temperatures, most drymarchon keepers agree that the eggs should be incubated at cooler temps that most other snakes. I keep my eggs at about 75 degrees and I’ve found that to be effective. Temps below 72 can prevent the embryos from developing properly, and temps above 78 can result in spinal kinks and other deformities.
Because incubation temps are lower, drymarchon eggs also take longer to hatch than most other colubrids. Expect a 110-120 day incubation period. Once the babies start to pip, they should emerge from their eggs shortly thereafter. I like to remove the newly hatched snakes immediately and house them individually in shoeboxes. I have heard of a few cases where a hatchling drymarchon has consumed a sibling!
Now for the tough part… getting the little guys feeding. Because indigos and cribos have such a wide variety of dietary preferences, it’s often difficult to figure out what they want. Some may go straight to pinky mice, but many will refuse and be holding out for something else. This can be a frustrating process that requires a lot of patience. With other colubrids like gray-banded kings, a breeder knows that if they don’t want mice, they want lizards. It’s not so easy with drymarchon babies. I’ve had babies start feeding on a number of different things. Keep trying, stay patient, and sooner or later, you’ll find what works.
When I have a clutch of babies that have just finished their first shedding cycle, I first offer unscented pinky mice. If that doesn’t work, I scent the rodents with fish. I’ve used goldfish, and rosy red minnows to scent with, and this seems to get a lot of them going. You can also use fish filets from the supermarket like tilapia or catfish. If that doesn’t work, scenting with quail or chicks often does. Nearly all of my babies start on either fish or poultry of some sort. If I have a really finicky baby, I will often resort to snakes, lizards, or frogs.
One of the important things to remember is that the need to get them going on rodents can be overstated by some breeders. As mentioned above, these guys eat a litany of different food items, and in fact, my animals seem to prefer rodents the least! Don’t feel like you need to be in a rush to get them switched over to rodents. They key is to get them feeding… period! If they are not taking scented rodents, then feed them whatever you are scenting with… day old button quail, chick legs, goldfish… anything! You’ll find once they have a few meals- regardless of what the prey item is- they will start consuming anything and everything!
There are certainly many breeders out there with a lot more drymarchon experience than I have. I, by no means, think of myself as an expert and I have a lot yet to learn. Much of the above was learned by experience, but also by conversing and sharing ideas with other breeders. I’m always willing to learn, and to change my methods in order to become a more successful breeder. It’s a labor of love, and the learning curve is never-ending. The good news is it’s a fun learning curve, so enjoy!