boa constrictorScientific Name– Boa constrictor

Conservation Status– Not evaluated


While regularly considered to be one of the largest snakes they are modest in comparison to the largest snakes. The maximum length attained by boa constrictors is 3-13 feet (approximately 1-4m). The female boa is usually larger than the males. The average size of a boa is 7-10 feet for females and 6-8 for males.

The female boa constrictor will generally weigh 10 to 15kg with some specimens achieving weights of up to 27kg.

The colouring of the boa features a cream, brown or grey base colour. They then have brown or red patches on the back known as saddles. These saddles are more pronounced as they move towards the tail.


The boa constrictor reaches an average 20 years in the wild and may occasionally reach 35 years in captivity.


The boa constrictor is a carnivore. The main prey items of the boa constrictor are small mammals. They will take any animal though, which they can fit in their mouths.


The boa constrictor is found throughout South and Central America. They can found throughout Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Colombia and Ecuador. They also range through Trinidad and Tobago, Guyana, Belize, Suriname, French Guiana, Brazil, Bolivia, Uruguay and Argentina. There are also some populations on the islands off the coast off these countries.

While they can be found in a range of habitats such as semi-deserts, open savannah and cultivated fields they thrive in tropical rainforests. These areas provide cover and the correct environmental conditions. They are competent swimmers and can regularly be found near bodies of water.


The boa constrictor will breed during the dry season which is normally April to August. The male will wrestle for the right to mate the females. They are attracted by the scent the female emits from her cloaca. The female will breed once every 2 years.

After mating the female can store the sperm for up to a year. When she ovulates the stored sperm will fertilise the egg. During this period the middle of the body swell to a similar size as if she has eaten a large meal.

After ovulation a shed will occur that is longer than this. The gestation period of 100-120 days is then counted after this. The female gives birth to 10 to 64 eggs with an average of 25. These young are independent within a few minutes.


The boa constrictor is a solitary species. They emerge mostly at nights but sometimes will bask in the sun throughout the day when it is colder.

The boa constrictor goes through a shedding period occasionally. During this time oil under the skin lubricates it to move it off. This also builds up under the eye. This blocks their vision and leads to them becoming inactive for a couple of days. During this period they are also more defensive.

When young they are mostly found in the trees but they move back to the ground as they become older and heavier.

Quick facts

The boa constrictor is regularly kept as a pet

Photo Sources

By Tod Baker from Tianjin, China (Constrictor Constrictor) [CC-BY-SA-2.0 (], via Wikimedia Commons