The boa constrictor, also called the common boa or the red-tailed boa, is a species of large, non-venomous, heavy-bodied snake mostly kept and bred in captivity.
The boa constrictor is a well-known member of the Boidae family, mostly found in tropical South America and some Caribbean islands.
Its color pattern is highly variable and recognizable, a hallmark of private collections and public displays.
While some of these are contentious, nine subspecies are currently recognized.
Scientific classification
| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Reptilia |
| Order | Squamata |
| Suborder | Serpentes |
| Family | Boidae |
| Genus | Boa |
| Scientific Name | Boa constrictor |
Subspecies
| Subspecies | Distribution |
| Amaral’s boa (B. c. amarali) | Bolivia, Brazil, and Paraguay. |
| red-tailed boa (B. c. constrictor) | South America |
| Peruvian long-tailed boa (B. c. longicauda) | northern Peru |
| Ecuadorian boa (B. c. melanogaster) | Ecuador |
| Argentine boa (B. c. occidentalis) | Argentina and Praguay. |
| Orton’s boa (B. c. ortonii) | South America |
| Pearl Island boa (B. c. sabogae) | “Pearl Islands” off the coast of Panama |
Characteristics
The boa constrictor is a large snake, but it is only modestly scaled compared to other large snakes, such as the reticulated python, Burmese python, or the sometimes sympatric green anaconda. It can reach lengths of 0.91 to 3.96 m (3 to 13 ft) depending on the location and the availability of suitable prey.
The species exhibits strong sexual dimorphism, with females usually larger in both girth and length than males.
The normal size of mature female boas is between 2.1 and 3.0 m (7 and 10 ft), while males are 1.8 and 2.4 m (6 and 8 ft).
Females usually exceed 3.0 m (10 ft), especially in captivity, where lengths of up to 3.7 m (12 ft) or even 4.3 m (14 ft) can be seen.
At the Zoologische Staatssammlung München (ZSM 4961/2012), the largest recorded non-stretched dry skin is stored and measures 14.6 ft (14.3 m).
The boa constrictor is considered a heavy-bodied snake and can weigh up to 60 lb (27 kg) (large specimens).
Generally, females, the larger sex, can weigh 22 to 33 lb (10 to 15 kg). Some Individuals of this species can reach or exceed 100 lb (45 kg), although this is not customary.
A boa constrictor’s size and weight depend on the subspecies, availability of suitable prey, and locale. B. c. Constrictor meets the averages given above and sometimes tops them, as it is one of the relatively large Boa constrictor subspecies.
Scalation
Boa imperator has 50 to 95 dorsal scales, 223 to 252 ventral scales, 43 to 69 subcaudal scales, 19 to 25 supralabial scales, and 1 to 3 anal scales.
Coloring
The coloring of boa constrictors can vary greatly depending on the locality. They generally have a brown, grey, or cream base color, patterned with “saddles” of brown or reddish-brown that become more pronounced towards the tail.
This coloring gives the B. constrictor species the common name of the “red-tailed boas.
There are pigment defects in some specimens, such as albinism. While these specimens are uncommon in the wild, in captivity, they are common, where they are often selectively bred to produce a range of “morphs” of different colors.
The arrow-shaped head of the Boa constrictors has very distinctive stripes: one extends from the snout to the back of the head dorsally; the other runs from the snout to the eyes and then from the jaw.
Behavior
Boa constrictors usually live independently and do not associate with any other snakes unless they wish to mate.
They are nocturnal, but they may bask during the day when night-time temperatures are too low.
Young boa constrictors can climb into trees and shrubs to forage as semi-arboreal snakes; however, they become more terrestrial as they become older and heavier.
When they perceive a threat, Boa constrictors strike. Their bites, particularly from large snakes, can be painful but rarely harm humans.
Like all snakes, Boa constrictors are more unstable in a shed cycle since the material that lubricates between the old skin and the new makes their eyes look milky.
Their eyes may also appear blue or opaque, so the snake cannot see very well, making them more defensive than usual.
Reproduction
The boa constrictor is viviparous, giving birth to live offspring. They usually breed between April and August (dry season) and are polygynous, with males mating with multiple females.
Half of all females breed in a given year, and more males actively try to find a mate. Many of these males would be ineffective due to their polygynous nature.
As such, if they do mate, female boas are unlikely to attempt to mate in poor physical health or to produce viable young people. Reproduction is almost exclusively sexual in boas.
Terminal automixis, a type of parthenogenesis in which two terminal haploid meiosis products fuse to form a zygote, which then develops into a daughter progeny, was probably developed by the WW females.
This is the third genetically confirmed case of successive virgin births of viable offspring within any vertebrate lineage from a single female.
Males were found to contain a pair of chromosomes defining the XY sex, while females have a pair of XX.
The female boa releases pheromones from her cloaca during the breeding season to attract males, who will then wrestle to pick one to breed with her.
The male coils his tail around the female during breeding, and the hemipenes (or male reproductive organs) are inserted.
Copulation may last from a few minutes to several hours and occur multiple times over a few weeks.
Ovulation may not occur immediately after this period, but the female may keep the sperm within for up to one year.
The female sheds 2 to 3 weeks after ovulation, referred to as a post-ovulation shed, lasts for another two to three weeks.
The gestation period counted from the postovulation shed is approximately 100 to 120 days. The female then gives birth to offspring with an average length of 38 to 51 cm (15 to 20 in).
The litter size varies between females but can be between 10 and 65 offspring, with an average of 25, although some of the young eggs may be unfertilized or stillborn (also known as slugs).
At birth, the offspring are independent and develop rapidly for the first few years, shedding frequently (once every 1 to 2 months).
Boa constrictors become sexually mature at 3 to 4 years and reach 1.8 to 3.0 m (6 to 10 feet) in adult size, although they continue to grow for the rest of their lives at a slow rate.
At this point, they shed less regularly, about every 2 to 4 months.
Hunting and diet
A wide range of small to medium-sized mammals and birds are included in their prey. Most of their diet consists of rodents, but they eat larger lizards and mammals as large as ocelots.
Young boa constrictors eat small mice, birds, bats, lizards, and amphibians. As they grow older and bigger, the size of the prey item also increases.
Boa constrictors are ambush hunters, so they often lie in wait for suitable prey to come along and strike.
First, the boa hits the prey, grabbing it with his teeth; then, before swallowing it whole, it constricts the prey until death.
Instead of suffocation, as previously thought, unconsciousness and death are likely to result from cutting off critical blood flow to the heart and brain; constriction will interfere with blood flow and overwhelm the normal blood pressure and circulation of the prey.
This can quickly lead to unconsciousness and death. Their teeth also help push the animal down the throat and then move it toward the stomach with the aid of muscles.
Depending on the size of the prey and the local temperature, it takes the snake about 4 to 6 days to digest the food completely. After eating, the snake might not feed for a week or even for several months due to its slow metabolism.
Distribution and Habitat
Boa constrictor can be found north of 35 ° S in South America (Colombia, Ecuador, Guyana, Suriname, Peru, Venezuela, Trinidad and Tobago, French Guiana, Brazil, Bolivia, Uruguay, and Argentina) and several other islands along the coasts of South America, depending on the subspecies.
B. constrictor, in a wide range of environmental conditions, from tropical rainforests to arid semi-desert countries, flourishes.
But, due to temperature and humidity, natural protection from predators, and large quantities of potential prey, it tends to live in the rainforest.
It is often found in streams and rivers or close to them, as it is a good swimmer. The caves of medium-sized mammals are also inhabited by Boa constrictors, where they can hide from possible predators.
