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Corallus & Bats

Ringed tree boas (Corallus annulatus) are one of five boa species in Costa Rica. They are nocturnal and arboreal, coiling neatly around tree trunks and high up among branches. In the literature, this species is supposedly rare in contrast to other Corallus species in Central and South America— with exception of the Brazilian C. cropanii, only known from a number of specimens. But over the past six years my luck has been relatively good with finding them, especially on rainy nights. I have even encountered ringed tree boas more frequently than boa constrictors… though this is likely the case because C. annulatus prefer intact lowland rainforests whereas constrictors are omnipresent. Diet records for ringed tree boas are scarce; they are known to prey on birds, bats, rodents, and probably small marsupials like mouse opposums (e.g., Marmosa zeledoni). It is possible that younger boas take smaller lizards, a specialization well known for the juveniles of West Indian species (C. cooki & C. grenadensis). However, it appears that other Corallus from the mainland mostly stick with endothermic prey. Tree boas are armed with rows of thin needle-like teeth and a powerful constricting grip, enabling them to have an exceptionally high success rate of prey capture. The grip strength of even a moderately-sized boa is astounding to feel, and if obstinate, can only be removed by unwrapping from the tail end.

Scroll down to see color variation in C. annulatus including a light-colored juvenile, an orange subadult, and a yellow adult; all photographed after disturbance [4]

One of dozens of dog-like bats (Peropteryx sp.) inside a dead hollow tree, either P. kappleri or P. macrotis— difficult to distinguish without measuring body size and dentition. One ringed tree boa has been spotted here in ambush posture to prey on the bats. Photographed in situ [1]
A Peropteryx pup observed several nights in a row adjacent to its two parents on an exposed fallen tree; photographed in situ [1]
A juvenile C. annulatus, the smallest individual I have encountered to date
An adult ringed tree boa, with more of a typical coloration that I’m familiar with from the Caribbean versant of Costa Rica
A colony of greater sac-winged bats (Saccopteryx bilineata) that has been observed in the same spot every day without fail for decades! Note the pups hiding under their parents’ protection. Photographed in situ [1]
Though similar in dorsal pattern, proboscis bats (Rhynchonycteris naso) differ from sac-winged bats by a more mottled coloration, hair tufts on the forelegs, and a more pointed snout. I spotted this group while going down the Sarapiquí River. It’s amazing that they can withstand being in direct sunlight! Photographed in situ [1]
A diurnal predator counterpart for bats, the aptly-named bat falcon (Falco rufigularis); composite of two images stitched together. Photographed in situ [1]

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