Lucas Bustamante / Red tailed boa constrictor (Boa constrictor constrictor) juvenile, portrait, with tail wrapped round head, Cuayabeno, Sucumbios, Ecuador.

John Cancalosi / Boa Constrictor (Boa constrictor) shedding skin from head. Guanacaste National Park, Costa Rican tropical rainforest.

John Cancalosi / Boa Constrictor (Boa constrictor) shedding skin from head. Guanacaste National Park, Costa Rican tropical rainforest.

Michael D. Kern / Red Tailed Boa {Boa constrictor constrictor} captive, from South America

Mary McDonald / Boa constrictor (Constrictor constrictor). South America

Pete Oxford / Boa Constrictor (Boa constrictor) coiled around a mossy tree branch in the rainforest, South America

Jen Guyton / Pale morph Boa constrictor (Boa constrictor) from Tayrona National Park, Colombia. Controlled conditions.

Jen Guyton / Boa constrictor (Boa constrictor) Tayrona National Park, Colombia.

Lucas Bustamante / Red tailed boa constrictor (Boa constrictor) on fallen tree over water, Yasuni National Park, Orellana, Ecuador.

Ingo Arndt / Madagascar boa constrictor {Acrantophis madagascariensis} captive

Pascal Kobeh / Dumeril's ground boa (Acrantophis dumerili) held by a guide, Nosy Be, Madagascar

MYN / JP Lawrence / Young Boa constrictor (Boa constrictor) Gamboa, Panama. Meetyourneighbours.net project