Thank you for your question. Without being able to count scales to try to determine the subspecies of boa you have, based on the coloration of the tail in your photo, I believe your boa is probably Boa constrictor imperator, commonly referred to as the Central American boa, Colombian boa, northern boa and common northern boa. This species is sometimes referred to as a red-tail boa in the pet trade. The tail is reddish in color, but is usually more brown or darker red than the species referred to as the red-tail boa. It is found in Mexico, Central America and Colombia. This species is normally approximately 4 - 8 feet in length.
The red-tail boa, Boa constrictor constrictor, is found in South America (Colombia, Ecuador, Peru, Venezuela, Trinidad, Tobago, Guyana, Suriname, French Guiana, Brazil, Bolivia, Uruguay and Argentina). This species is normally approximately 3 - 13 feet in length.
I hope this information helps, and thank you for contacting Ask an Expert.