Diet and body condition of cave‐dwelling dwarf crocodiles (Osteolaemus tetraspis, Cope 1861) in Gabon

Abstract

We present the first ever observations of dwarf crocodiles (Osteolaemus tetraspis) selectively utilizing a cave ecosystem. We analysed crocodile diet to preliminarily assess the degree of ecological isolation of cave‐dwelling crocodiles from their forest‐dwelling conspecifics despite their physical proximity. We additionally conducted the first study of body condition of dwarf crocodiles and compared cave‐dwelling individuals to surface‐dwelling individuals from a variety of alternative habitats and sites as a means to better understand the implications of a semihypogean life on this species. Crocodiles captured in the caves appeared to forage exclusively in the caves and ate mostly cave crickets and bats, whereas crocodiles captured in the surrounding forest habitat consumed primarily freshwater crustaceans and insects and were not found to consume cave‐dwelling prey. Juvenile cave crocodiles had significantly higher body condition compared to juvenile forest crocodiles, which did not vary amongst forest locations. The difference in body condition between adult cave and forest crocodiles was not statistically significant despite also being higher; we suspect this is an artefact of the low sample size rather than a real nondifference. Forest adult crocodiles generally had significantly higher body condition than juveniles, but did not vary by site or habitat. This lack of variation suggests that habitat type is not the most important factor influencing dwarf crocodile body condition. Our results provide a unique insight into facultative cave use by a principally surface‐dwelling species and reinforce the necessity for further research into this unique system to better understand the evolutionary‐scale implications of cave habitat use by dwarf crocodiles.

Virtual reconstruction of the skull ofBernissartia fagesiiand current understanding of the neosuchian–eusuchian transition

“…corresponding to that of tetraspis from equatorial forests of Africa, which displays posterior blunt dentition and does not surpass 2 meters in total body length. Its diet has been described as opportunistic with stomach contents containing primarily crustaceans, insects, amphibians and small mammals (Pauwels et al 2007;Shirley et al 2016). Again in the case of B. fagesii, it is difficult to evaluate the diet of an extinct taxon when stomach content is absent but O. tetraspis might be a good approximation for the diet of B. fagesii.…”

Use of diet and body condition assessments as intermediate indicators of translocation success in the Critically Endangered Philippine crocodile (Crocodylus mindorensis)

“…Body condition indices, such as Fulton's condition factor (K) and the relative condition factor (K n ) (Le Cren, 1951), are regularly used as indicators of crocodylian health and well-being (Elsey et al, 1992;Rice, 2004;Fujisaki et al, 2009;Mazzotti et al, 2012;Shirley et al, 2016) Ten were headstarted (nine females, one male), released an average of 5.65 years before capture, including six juveniles and four adults ranging in length from 72.3 to 169.9 cm TL (SVL: 36.6-90.4 cm; X = 82.9 ± 5.74 cm). Both groups were of similar length (SVL: t = À1.62, P = 0.116).…”

Nesting Ecology of West African Dwarf Crocodiles in a Heavily Disturbed Landscape in Chirehin, Ghana

“…African dwarf crocodiles (genus Osteolaemus) are relatively small, secretive, and docile crocodilians that are endemic to western Africa from the Democratic Republic of Congo to e Gambia [1,2]. African dwarf crocodiles typically inhabit forest streams, isolated pools, and swamps where access to sunlight is limited [3][4][5][6][7].…”

“…Despite its threatened status, dwarf crocodiles are still among the least studied crocodilians in the world [2]. For the past three decades, there have been a handful of studies on the basic ecology of wild populations of dwarf crocodiles in West Africa [3,6,7,9].…”