Orinoco Crocodile

Orinoco Crocodile

The Orinoco crocodile is the largest crocodile of the Neotropics [1] and lives exclusively in the Orinoco River Basin of Columbia and the Meta River basin of Venezuela [2]. Due to fragmented population, the ecology of the species is poorly known, and is largely represented by anecdotical data [1].

Similar in size to the male American crocodile (22ft; 7m), Orinoco crocodile is identifiable by their dorsal spikes; six large scales on the back of the neck. They lack dermal bone structure on their stomachs, and sport a narrow snout which slopes upward near the nostrils [3]. Rather unusually, the Orinoco crocodile does not have any subspecies [3]. Their body varies in colour from gray-green (mariposo) to tan (amarillo). They are largely piscivorous, feeding on fish and invertebrates, but may consume capybara or other small to medium mammals in adulthood [4]. Juvenile and hatchling crocodiles typically feed on crabs, snails, insects, and small fish [3]. Without environmental factors (global warming, poaching), it is possible that Orinoco crocodiles may reach a lifespan of 70–80 years.

Orinoco Crocodiles are the most southerly crocodiles in the western hemisphere. During the rainy season, they travel over land to ponds and lakes, returning when the river water recedes. In the dry season, they live in a doremant state in excavated burrows [4]. Orinoco crocodiles are typically social, living in dominance-based hierarchy (3). Their communication system consists of bellowing and chuffing, with gutteral growls. When experiencing brooding, female Orinoco crodiles (both in captivity and the wild) have been known to become highly aggressive.

Adult pairs mate in this dry season: from December to January or July to August, and females often outnumber males 2:1 [2]. Females typically will lay 40-60 eggs, and they incubate over the course of three months (75-85 days approximately). When newly hatched, the mother will dig the hatchlings from their nest and carry them to the rising river's edge. Young Orinoco are preyed upon by various species of tegu, vultures, anacondas, and potentially jaguars. It is a high risk for predators, and they are often killed by mother crocodile. As adults, Orinoco Crocodiles lack predation besides humans [3]. Due to the quality of their skin, lack of dermal bones in their belly, and large size, hunting the Orinoco Crocodile proved to be a straightforward way to make a lump sum from a single animal [4]. Commercial exploitation started in the late 1920s, in both Columbia and Venezuela. From 1930 - 1935 is when the Orinoco crocodile received the biggest hit to their numbers, and the population was decimated by the 1960s [5].

To curb risk of extinction, the best choice of conservation action has been focused on reproducing in captivity, and reintroducing reared Orinoco crocodiles into the river basin. Due to ongoing conflict in Columbia, repopulation and documentation of success largely began in 2018 [1]. Satellite transmitters have been deployed on captive-reared crocodiles to monitor movement for up to 2 years [1]. The Orinoco crocodile is legally protected in Venezuela by a presidental decree, which came in to effect in 1996 [5].

The Orinoco Crocodile is classified by the IUCN as Critically Endangered; there are less than 1,500 adult crocodiles in the range of the Orinoco River to the Meta River (as of a 2022 survey) [1].