The Orinoco crocodile (Crocodylus intermedius), is a critically endangered crocodile. Its population is very small, estimated at only 547 in the wild and it can only be found in freshwater environments in Colombia and Venezuela of northern South America, in particular the Orinoco River and its tributaries. Extensively hunted for their skins in the 19th and 20th centuries, this species is one of the most critically endangered species of extant crocodiles. It is a very large species, in fact the largest species of crocodilian and predator in the Americas. Males have been reported up to 6.6 m (22 ft) in the past but such sizes do not exist today, 5.2 m (17 ft) being a more widely accepted maximum size. Males average at 4.1 m (13 ft) in length weighing 380 kg (840 lb), while females are slightly smaller averaging at 225 kg (500 lb). Sexual dimorphism isn't as profound as in some other species. The coloration is light even in adults.

The biology of the Orinoco crocodile is poorly documented in the wild, mostly due its small population. It is thought to have a more piscivorous diet with an opportunistic nature resulting in a generalist predatory behavior. The Orinoco crocodile is and apex predator and will take the opportunity to prey on a variety of reptiles, birds and mammals, including caimans on occasion. The prey base is mostly made up of large predatory fish, challenging the general view by the locals complaining about the crocodile hunting local fish to very low numbers. Despite its large size, the Orinoco crocodile rarely poses a threat to humans, despite several reports. Reproduction takes place in the dry season when the water level is lower. The Orinoco crocodile is a hole nester, digging holes in the sand to lay their eggs. The female guards the nest and young up to several years.

Characteristics [edit]

The Orinoco crocodile can be recognised by its relatively long snout, which is narrower than that of the somewhat similar-looking American crocodile. This species generally has a pale tan hide, though at least three coloration variations are known, with some almost completely yellowish and some a dark brownish-gray. It has been noted that the skin can change colour over long periods of time; this phenomenon has been recorded in other species that can gradually change the amount of melanin in their skin. These crocodiles have dark brown markings, which present as more pronounced bands in younger specimens and as scattered markings on mature ones.

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Size [edit]

The Orinoco Crocodile ranks among the largest living reptiles as well as the largest predator in South America. Typically, males are 3.6 m (12 ft) to 4.8 m (16 ft) in length, weighing 380 kg (840 lb) to 635 kg (1,400 lb), while females are typically 3 m (9.8 ft) to 3.3 m (11 ft) in length, weighing 225 kg (500 lb) to 317 kg (700 lb).^[3] The largest specimen reported was shot in 1800, and allegedly measured at 6.6 m (22 ft).^[4] Due to extensive hunting for their skins in the 20th century, such giants do not exist today, and modern Orinoco crocodiles have not been reported to exceed 5.1 m (17 ft) in length.^[5] It is the largest crocodilian in the Americas, while American crocodiles and black caimans approach similar dimensions, on average the Orinoco crocodile is slightly larger.

Distribution and habitat [edit]

This species is restricted to the Orinoco River basin in Colombia and Venezuela. They have been occasionally reported on the island of Trinidad, but this has not been confirmed and witnesses may have mistaken an American crocodile for the rarer species. This crocodile was once thought to have once inhabited a wide range of riparian habitats, from tropical forests to the streams of the Andes foothills. Today, this species is restricted to the Llanos savannah and associated seasonal freshwater rivers.

Biology and behavior [edit]

Hunting and diet [edit]

The majority of the Orinoco crocodile's diet consists of large fish, their relatively narrow snout is ideally suited to minimize water resistance in capturing piscivorous prey. However, as an opportunistic apex predator virtually any animal living within its range could be considered a potential meal, such as reptiles, birds and mammals. Despite the fact that it has a rather elongated skull, the width of the base snout is wide, hinting to a generalist diet. It will stalk both aquatic and terrestrial prey. As a large adult, terrestrial prey may include, capybara, domestic animals, and even occasionally other large predators if the opportunity arises.^[2] Similar to many of the larger crocodile species, the Orinoco crocodile has also been observed catching and eating smaller species of crocodilians, such as caimans and sometimes cannibalizing on smaller individuals of its own kind. There have been reports of attacks on humans, but this is highly unlikely that this is a common behavior, given the extremely low population level of the species and its relative isolation from large human settlements. Its large size may pose a threat but reducing the likelihood of predation on humans, it can be said that this species has a relatively less aggressive temperament compared to other large crocodiles.

Reproduction [edit]

When water recedes in the dry season, Orinoco crocodiles retreat to burrows they excavate into the riverbanks. The adult pair mates during the drier period of the year and usually 14 weeks after mating, the female crocodile will dig a nest and lay approximately 40 eggs. It is a hole-nester and usually makes the nest on a sand bank. The eggs incubate for around 3 months. During the night they hatch and call to their mother who digs them out of the nest and carries them to the water, which is considerably higher at this point. Young Orinoco crocodiles are often at risk from predation by American Black Vultures, tegu lizards, anacondas, caimans, coatis, jaguars and other carnivores, though these species are sometimes caught and killed by the defending mother crocodile. It has been reported that mothers have defended pods of juveniles for over 3 years, though closer to one year to independence is generally most common.^[2]

Crocodylus intermedius

Conservation status [edit]

The Orinoco crocodile is highly endangered due to excessive hunting for its hide. During the 1940s to the 1960s, literally thousands of these animals were slaughtered in the Orinoco River and the Llanos wetlands, and the species came very close to extinction. The Orinoco crocodile was given protected status in the 1970s but has yet to recover successfully. Today it is protected both in Venezuela and Colombia, and also included on Appendix I by CITES. In addition to hunting for its hide, more recent threats also include the collection of juveniles for sale in the live animal trade, pollution, and the proposal of a dam in the upper Orinoco River region. Another problem is the increased population of Spectacled caimans, a smaller crocodilian that can outcompete the Orinoco crocodile for fish due to its much larger population and much more accelerated breeding rates.^[2]

It is unclear how many individuals remain in the wild, but estimates range between 250-1500 individuals. The population in Colombia is very low, with the largest sub-population estimated at around 50 individuals in the Casanare area. The largest sub-population in Venezuela is in Cojedes and Sararé, with less than 500 adults remaining. A number of other smaller sub-populations exist.

In November 2007, 50 individuals were held in zoos registered by ISIS, of which the largest population, 35 individuals, were kept in the Dallas World Aquarium. Additionally, a large number of individuals are held at captive breeding facilities in Venezuela. Since the early 1990s, a large number of hatchlings have been released both into private ranchlands (especially in the Llanos where nature oriented tourism is important for the local economy) and in national parks in Venezuela. As many hatchlings die before reaching adulthood, 360 captive-bred individuals have been released only after reaching a length of 2 m (6.6 ft).

References [edit]

Wikispecies has information related to: Crocodylus intermedius

• Captives held in zoo's registered by ISIS.
• Information on Crocodylus intermedius. ARKIVE.
• IUCN/SSC Crocodylus intermedius. Crocodile Specialist Group - Status Survey and Conservation Action Plan, 2nd edition.
• Promise for the Survival of the Orinoco Crocodile: a strong commitment from the private sector in Venezuela