Boids

Who has never heard of the famous Anaconda or the Boa constrictor? Less well known, but also part of this family, are the small sand boas and the pythons.

The Boidae family belongs to the boid superfamily, together with the Xenopeltidae, Loxocemidae, Bolyeriidae and Tropidophiidae. It is divided into three subfamilies: the Boinae (boas), the Pythoninae (pythons) and the Erycinae (sand boas). Boids are best known thanks to the giant snakes. With the exception of a few specimens, these powerful constrictors have a head clearly distinct from the body. Their mouth can open very wide owing to the mobility of the upper jaw and the mandibles.

In addition to differences in the anatomy of their skull, pythons differ from boas because they lay eggs (oviparous), but also because almost all of them have heat-sensitive pits. It should be noted, however, that some boas also have these pits, allowing them infrared vision. Boas are ovoviviparous (their young are born live), with the exception of the Charina boa.

In general, boas occupy the southern half of the American continent and Madagascar, while pythons are found in Africa, Australia, India and Indonesia and on the Pacific islands. The burrowing boas, for their part, are present in North America, in Africa, and from the Arabian Peninsula as far as India.

REPRODUCTION

Determining sex, size and sexual maturity

Determining the sex of boids is not always straightforward, as few species show obvious sexual dimorphism. The most widely used method, and for now the most reliable, is to probe the animals.

This technique, which should be reserved for the veterinarian, consists of gently introducing a lubricated metal probe through the cloaca, towards the tail. In the male, the probe will slide in deeply into the space where the hemipenes are housed (on average 10-12 subcaudal scales). In the female, the probe goes in only slightly (2-4 subcaudal scales).

Sexual maturity is reached on average between 3 and 5 years in most pythons and boas.

The first condition for animals to breed in captivity is that they be in perfect health. Snakes that are too fat or too thin are rarely good breeders.

In the wild, they breed according to the cycle of the seasons. The periods depend on temperatures, rainfall and the photoperiod (length of daylight).

In captivity, one must therefore try to reproduce the climatic changes in order to stimulate the animals.

Gestation, birth, incubation.

In boas, the length of gestation is difficult to estimate, as mating extends over a long period. In general, gestation lasts 4 to 8 months depending on the species. During this period, the snake should be provided with a warm spot that is more intense than usual. Baby boas are born in yolk sacs from which they free themselves easily. Litters range from 4 newborns to 60 for a large female.

In pythons, the period between ovulation and egg-laying lasts 2 months; a shed occurs before laying. The number of days between the shed and laying is specific to each species. The females coil around the eggs, where they remain until hatching.

In several species, it has been observed that they are able to raise their body temperature to keep the eggs at the right temperature. In captivity, incubation can be left to the mother or else carried out artificially. Incubation lasts about 60 days at 30-31 degrees, with a humidity level of 95% to 100% (varies depending on the species).

A few details about the most widespread boid species?

The royal python

Common name: Python regius or ball python. Adult size: 1.0 to 1.80 m.

Distribution: West and Central Africa (grassland, savannahs, wooded plains, dry tropical forests).

It is the smallest python on the African continent. It has a stocky body and a relatively short tail. The head, very dark brown to black in colour, is clearly distinct from the neck, and a row of loreal pits is visible on either side of the mandible. The base colour ranges from golden yellow to dark brown, with markings sometimes edged in white. The ball python owes its name to the fact that, when disturbed or stressed, it rolls into a compact ball with its head placed in the centre. So, although very docile, it is nonetheless shy.

The python does not require a particularly large terrarium. Dimensions of 100x60x60 cm are perfectly adequate. A warm spot of 25 to 35 degrees at the hottest point will be comfortable, while at night temperatures of 22/25 degrees are preferable.

The Burmese python

Common name: Python molurus bivittatus, Burmese python

Adult size: 3.5 to 6.0 m

Distribution: southern Asia; lives in wooded areas and tropical forests.

It is one of the giants of the boid family; it is very massive and can weigh up to 130 kg. The head is relatively rectangular, with a characteristic pinkish-beige V shape drawn on the top of the head. The more or less dark brown background colour is marbled with elongated light-beige, yellowish markings. Other striking colours exist, owing to the development of the species in captivity, such as the albino (yellow and white), the green (khaki green + brown patch), or else 'granite', 'labyrinth', etc.

To house adult specimens up to 3.50 m, a terrarium of 250x125x125 cm is sufficient. For animals between 4 and 6 metres (the size of a female), however, one no longer speaks of a terrarium but of a small room of 3x3 m. It is fairly easy to care for, hardy and not very aggressive. It can live for 30 years if kept in good conditions.

The Boa constrictor spp.

Common name: boa constrictor

Adult size: 1.5 to 4.2 m

Distribution: Central and South America, tropical forests, wet or dry savannahs and semi-arid areas

It is surely the most widely kept 'big' snake in the world. Its generally docile temperament, its varied colours and patterns (linked either to the different subspecies or to selective breeding of individuals), its ease of care as well as its ability to breed have all contributed to its popularity. This snake requires a terrarium of at least 200x60x80 cm to house an adult pair of 2.5 to 3 m. It can be made of wood at least 12 mm thick and well ventilated, and the panes should be of an equal thickness of at least 5 mm.

Heating will be provided using heating elements, or a heat mat placed under the terrarium and controlled by a thermostat.

Apart from the fact that it can grow large and therefore potentially dangerous, it is a snake that presents no particular difficulty in keeping. Its terrarium and its water bowl should always be clean, and the floor covered with newspaper or a suitable substrate.

It feeds on rodents such as rat, guinea pig, rabbit, or poultry.

A few tips…

• The terrarium or room containing the snake must be fitted with an escape-proof locking system, bearing in mind that snakes are experts at this.
• The buyer should take care to select a young animal from among the least aggressive.
• From its earliest age and for as long as it lives, the snake should be handled several times a week by its keeper in order to maintain a calm temperament.
• Handling should never be carried out after contact with potential prey. Reptiles have a keen sense of smell, but their eyesight is much less so.
• Food should be given through a different access point from the one used for routine visits.
• It is worth bearing in mind that every animal owner is, in all respects, civilly and legally responsible for their animal.

Common diseases

In constrictor snakes (boas and pythons), most diseases are linked to terrarium conditions: heat, humidity and hygiene.

Bear in mind: a healthy snake depends on suitable heat, good humidity and a clean terrarium. Most problems come from one of these settings.

Small external parasites (mites) sometimes appear: they are tiny moving black dots on the skin. The snake then stays in its water bowl for long periods and rubs itself. These parasites spread easily.

A difficult shed leaves scraps of skin that will not come off, especially over the eyes. It is often due to a lack of humidity. You must never pull on the remaining skin.

Drooling, redness or a deposit in the mouth suggests a mouth infection ('mouth rot'). Bubbles, an open mouth, or wheezing when breathing signal a respiratory tract infection. Finally, regurgitation or a prolonged refusal to feed should always attract attention.