Caulker Cay Boas

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  • Boa constrictor imperator (LINNAEUS, 1758)
Natural Distribution
  • Caye Caulker, off the coast of Belize
Approximate Size
  • Males 1.0-1.2 meters (3-4 ft.)
  • Females 1.2.-1.4 meters (4-4 ft.)
Conservation Status
  • CITES Appendix II3

Caulker Cay Boas (Boa constrictor imperator) are a small insular locality boa from Caye Caulker, just off the coast of Belize in the Caribbean Sea.

The first (wild collected) Caulker Cay boas entered Herpetoculture in the early 1900’s, by a research graduate. These boas were purchased by Gus Rentfro (Rio Bravo Reptiles)1 and Gus later produced the first F1 offspring.


Caulker Cay are among the smallest of B. c. imperator insular boas, with females topping out around 1.5 meters (4.9 feet).  Adult Males are smaller, some reaching sexual maturity at only a meter in length2.

Caulkers are unique in color; they appear naturally anerythristic in color, almost entirely lacking red pigmentation. Their dorsal background color tends to be light grey in color, with darker grey nearly black dorsal saddles (22-24 saddles snout to vent). Their lateral (sides) are somewhat grey in color, with dark grey patter. The ventral (belly) these boas are a noticeably light grey, almost white in color, with dark grey and back speckles.

Some Caulkers do exhibit dark brown dorsal or tail saddles, where others are nearly black in color.

Interestingly, Caulkers are similar to some other insular boas (such as Hog Isles) where they can exhibit a different color hue depending on their temperature. This is most evident in the evenings when temperatures cool, and boas are more active.

These are still uncommon boas in Herpetoculture, although they’re a true pleasure to work with.

Caulker Cay Boas

  1. Island Type Boas – Vin Russo – Accessed Online (2016-11-19)
  2. Boa C. imperator Cay Caulker – Accessed Online (2016-11-19)
  3. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) – Appendices I, II and III (accessed Online, 2017)

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