Editor's note: Rico Walder, one of the foremost experts on green tree pythons passed away October 11, 2014. He was 49. In addition to working with
Editor's note: Rico Walder, one of the foremost experts on green tree pythons passed away October 11, 2014. He was 49. In addition to working with emerald tree boas, he was considered one of the top green tree python breeders in the world.
The emerald tree boa was discovered in 1758 by Carlos Linnaeus, who named the strikingly beautiful tree boa Corallus caninus. The genus name, Corallus, resulted from the coral-like color and pattern of the boa as a neonate; caninus came about due to the boa’s head and angled snout, which Linnaeus found reminiscent of a dog. The elongated maxillary teeth also resemble the canine teeth of dogs (as well as being proportionately longer than those belonging to any other non-venomous snake).
Based on locality, some herpetologists have considered whether the Amazon Basin form of the emerald tree boa should be classified as a new subspecies, and the name recently suggested for this morphological variant, though not yet widely accepted, is C. batesii.
Two Types of Emerald Tree Boa
There are two distinct types of emerald tree boa. The northern form is found in Guyana and Surinam and is known as the Guyana Shield or northern emerald tree boa. It is the most common emerald tree boa found in captivity. The second, less-common form is the Amazon Basin emerald tree boa. The former is found primarily in northern South America, whereas the latter inhabits regions of jungle along the Amazon River basin from southern Surinam, southern Guyana and southern Venezuela to Colombia, Peru and Brazil.
There are remarkable differences between these two geographically isolated boas in terms of morphology, scalation, temperament, coloration and markings. The northern emerald is a leaner, smaller emerald tree boa than the Amazon Basin emerald, with a lighter green coloration and dorsal markings that do not connect. Its head scalation and the scales of the snout are much larger than those of the basin form. Specimens are typically a rich but lighter shade of green with a typical white seesaw or lightning-bolt pattern, and the belly is white. It attains an adult length that’s between 4 and 6 feet, and its temperament is typically not as calm or trustworthy as that of the Amazon Basin emerald.
Amazon Basin emeralds have a yellow belly with a body color that is generally darker green with a white dorsal stripe, often bordered by some black coloration. Protruding from this stripe are bright white triangles, the tips of which extend down the sides of the body toward the belly. The Amazon Basin emerald is larger than the northern emerald, with some specimens approaching 9 feet in length.
In our opinion, the Amazon Basin emerald tree boa is a more desirable animal from a collector’s standpoint due to its impressive size, striking coloration and gentle nature. They make terrific display animals, are dog tame during the day and savage opportunistic feeders at night.
The emerald tree boa is listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), which means that its international trade is monitored and regulated. Under Brazilian law, no wild-collected or even captive-born emerald tree boas can be exported from Brazil.
There are a handful of reputable and successful breeders in the U.S. and Europe, including the authors as well as Ed Marino of emeraldtreeboas.com, who are working with a very broad and diverse gene pool of captive-born Amazon Basin emerald tree boas. To ensure a successful experience keeping these snakes, potential owners are urged to purchase captive-born snakes rather than wild-caught animals that come with associated problems (including an inability to adjust to captivity, stress, internal parasites, etc.).
Care for Pet Emerald Tree Boas
Adult emerald tree boas typically feed once every three weeks, shed every six months and defecate every two months or so. They need a stable environment in terms of humidity, temperature and ventilation.
Humidity needs to be non-condensing (in other words, there should be no water dripping down the sides of the enclosure) and in the 65- to 75-percent range. It helps if you can maintain some level of humidity in your snake room, which lessens the burden of creating and maintaining humidity inside the actual enclosure(s).
We use puppy pads (used to housebreak puppies) for our emerald tree boas’ cage substrate. The pads are misted in the morning for one minute, and the resulting moisture is then slowly released from the pads during the day, to augment the ambient humidity in the cage. We believe it is important to mist the substrate and not the snakes directly, as the evaporative cooling of a wet animal can cause its core body temperature to drop, with potential for respiratory issues (keep this in mind especially if you plan to use automatic misters in the enclosure).
Both forms of emerald tree boa do well with a daytime ambient high temperature of 84 degrees Fahrenheit, with a nighttime low of 78 degrees. It is critical to provide captive snakes with a temperature gradient, and positioning a heat panel at one end of the cage to heat the entire cage is an ideal mechanism for doing so. Place a thermostat sensor in the cooler side and keep it set to ensure the day and nighttime ambient temperatures mentioned previously. This will also ensure that the basking site at the hotter end of the enclosure will be in the 88- to 93-degrees range.
Ventilation needs to be finely balanced to maintain airflow without having fans blowing on your emerald tree boa and without drying out the cage. We use 3-inch, louvered vents in our adult emerald tree boa cages, but we also maintain a snake room ambient humidity in the 60-percent range.
Enclosures for Emerald Tree Boas
We designed our own emerald tree boa enclosures, and they were fabricated for us by Habitat Systems Limited. Our breeding enclosures for adult snakes measure 33 inches long, 28 inches deep and 28 inches tall. They are made of extruded PVC hollow core material, which is ideal for holding temperatures. Tempered glass doors use magnetic latches for easy operation. We also have planters containing live Pothos in all of our adult cages, to augment humidity and create more of a natural environment.
Juveniles are maintained in smaller versions of the adult enclosures, without plants. Newborns and snakes up to 2 years of age are kept in Habitat Systems racks using 5-gallon Rubbermaid polycarbonate clear tubs measuring 18 inches long by 12 inches deep by 9 inches tall. Perches in these enclosures are positioned so the snakes can reach the bottom of the tub easily to drink or strike at prey. The racks have embedded heat tape in the back half of the shelf floor and top to maintain a heat gradient. Humidity is controlled in each tub by the position of the water bowl over the heated section of the rack.
A display enclosure for a single adult emerald tree boa should be about 3 feet long, 21⁄2 feet tall and 21⁄2 feet deep. Clear sides are not recommended because they can make a snake feel insecure. An all-glass front is acceptable and plants, live or artificial, are recommended to provide some cover (live plants will also assist in maintaining humidity).
Emerald Tree Boa Hydration: The Key to Success
In the wild, emerald tree boas are frequently rained on and are accustomed to drinking fresh water. Therefore, keeping captive snakes adequately hydrated is essential for their overall health and well-being. A lack of hydration leads to retained stools with large urates, incomplete sheds and potentially stuck embryos during parturition.
Place water bowls for juveniles and adults higher in the enclosure, next to perches, and change the water frequently, at least once per week, to stimulate drinking. Emeralds seem able to sense fresh water, and we often see ours drinking immediately after clean water is presented.
Emerald tree boas have a tendency to retain their stools for long periods of time, which can result in pressure on the cloaca. Some believe that in the wild, emeralds defecate while it’s raining so that their scent is washed away, avoiding detection by predators. To stimulate this behavior, we have developed a temperature-controlled rain chamber, in which our animals are placed to stimulate a bowel movement, assist a shed or help with hydration. Our removable perches make a visit to the rain chamber convenient.
Although not mandatory for all emerald tree boa keepers, a rain chamber is a convenient way to help maintain your snake’s health. Typically, our emeralds will defecate within the first few minutes of being rained on inside the chamber, and will spend the next 20 minutes drinking from their coils or lapping water from the side of the chamber. We try to cycle adults through the chamber at least once a month or when needed (for example, if a shed is stuck). It is important to provide the rain chamber with a constant supply of clean, temperature-controlled water so the animals are not drinking recycled dirty water.
Our rain chamber is 50 inches tall by 30 inches long by 28 inches deep and is constructed of hollow-core, extruded PVC. The chamber has two adjustable nozzles on the ceiling and a drain that connects to a sink drain. We use tap water that is run through a temperature-control unit commonly used in commercial darkrooms. Water temperatures range between 86 and 90 degrees. The pressure is variable depending on the task. For example, if we are dealing with a stuck shed on an adult animal, a fine mist is used and the animal may stay in the chamber for several hours. If the objective is to induce a bowel movement, a more aggressive ‘rain’ is used and results can usually be seen in a matter of minutes.
Feeding Emerald Tree Boas
Emeralds are opportunistic ambush feeders and will remain frozen in their classic hanging ‘S’ position night after night while waiting for a small mammal or bird to scurry or fly by. Our job as keepers of these magnificent creatures is to resist the temptation to overfeed them. Emerald tree boas are naturally slender because of their arboreal lifestyle, and because they hunt virtually every night except when in shed or gravid, it is very easy to want to overfeed them.
We feed our adult females one medium (150 to 175 grams), frozen/thawed (F/T) rat every three weeks, and adult males get one small (75g to 125g) F/T rat every month or so. We especially want to keep the males lean, as lean males tend to be more aggressive breeders. Juveniles are fed every two to three weeks and neonates every 10 days or so. The usual pattern is two to three meals, followed by defecation. We usually will not feed a fourth meal until the snake defecates.
Getting newborn Amazon Basin emeralds to start eating can be particularly challenging, more so than the northern form. Litter size typically numbers seven to 10 offspring (though litters as large as 25 have been recorded), and food is not offered until after the first shed that occurs within two weeks from birth. Newborns are then offered F/T rat pinkies, which are held with tweezers over a hot vapor humidifier until they are hot to the touch prior to being offered. Typically, about half of a litter will take a F/T rat pinkie as its first meal. Babies that refuse are offered a live dwarf hamster or hopper mouse, left in a deli cup in their tubs overnight. About half of these will be accepted, leaving 25 percent of the litter needing to be assist-fed a rat-tail or mouse hopper.
The objective is to get stubborn neonates eating F/T rat pinkies as soon as possible. Once they have reached about 6 months of age, they should show a strong feeding interest and can then be switched to F/T rats of appropriate size, no more than 20 percent larger than the snake at mid body. As soon as this is accomplished, emerald tree boas should be easy and consistent feeders for life.
Rats are the ideal prey for emerald tree boas, from 4 to 6g pinkies for babies to 175g medium rats for adults. A 40 to 50g adult mouse is insufficient for any adult emerald, as it will barely sustain the snake, and definitely will not get a female to the 1,800 to 2,000g weight she should attain by her fourth birthday in order to be a healthy breeder.
Emerald Tree Boas Handle with Care
No emerald tree boa enjoys being handled and passed around like a common boa or ball python. The tail of emeralds less than 1 year old is also delicate and can be easily damaged, causing a kink. It’s recommended, therefore, that handling of any emerald tree boa be kept to a minimum.
When we need to remove our Amazon Basin emerald tree boas from their enclosures, they first need to be teased off their perches by lightly scratching their coiled tails with a fingernail to get them to release their grip. Never grab or pull an emerald tree boa from its perch, as this will not only stress the animal but will also damage its tail. This is why an enclosure with removable perches is recommended; they help minimize the complications of having to extricate an emerald from its perch.
As mentioned, Amazon Basin emerald tree boas are typically gentle and easygoing animals, while the northern emerald tree boa is more easily annoyed and will strike in defense if it feels the slightest bit threatened. This is why we prefer to work with Amazon Basins, which are breathtakingly stunning creatures that can be highly rewarding captives for intermediate and experienced keepers. Even beginners can be successful if they do their homework, create a stable environment and purchase an established captive-born animal from a breeder who will provide the after-sale support and guidance necessary for success. However, be forewarned: One Amazon Basin emerald tree boa is never enough. Once you have your first and discover how easy and enjoyable these guys are to keep, you will want others.
Steve Volk lives in Boulder, Colo., with his wife, golden retriever and about 65 Amazon Basin emerald tree boas. He has bred various boas and pythons over the last 30 years, and for the past eight has focused on the Amazon Basin emerald, with the objective of producing high-white, deep emerald green animals, as well as the ultra-rare, naturally occurring black or melanistic Amazon Basin emerald. He has a BS in Zoology from Duke University and a Doctor of Dental Surgery from the University of Missouri. Visit his website at amazonbasins.com.