Yellow anaconda

The Neo-Latin specific name notaeus derives from Ancient Greek: νωταίος, romanized: nōtaios, lit. 'dorsal' (νωταίος is a poetic form of νωτιαίος/nōtiaios). In distinguishing his new species Eunectes notaeus from Eunectes murinus, Edward Drinker Cope stated, "Dorsal scales are larger and in fewer rows."[3]

Close-up of head, at the Reptilium Terrarium and Desert Zoo, Landau, Germany

In the Ohrada Zoo, Hluboká nad Vltavou, Czech Republic

Adults grow to an average of 3.3 and 4.4 m (10 ft 10 in and 14 ft 5 in) in total length. Females are generally larger than males,[4] and have been reported up to 4.6 m (15 ft 1 in) in length.[2][5] They commonly weigh 25 to 35 kg (55 to 77 lb), but specimens weighing more than 55 kg (121 lb) have been observed.[6] The color pattern consists of a yellow, golden-tan or greenish-yellow ground color overlaid with a series of black or dark brown saddles, blotches, spots and streaks.[2]

The range of the yellow anaconda encompasses the drainage of the Paraguay River and its tributaries, from the Pantanal region in Bolivia, Paraguay, and western Brazil to northeastern Argentina[7] and northern Uruguay.[8] [9] It prefers mostly aquatic habitats, including swamps, marshes, and brush-covered banks of slow-moving rivers and streams.[4] The species appears to have been introduced in Florida, although it is unknown whether the small population (thought to derive from escaped pets) is reproductive.[10]

The yellow anaconda forages predominantly in shallow water in wetland habitats. Most predation occurs from June to November, when flooding has somewhat subsided and wading birds are the most common prey. Observations and analysis of gut and waste contents from regularly flooded areas in the Pantanal region of southwestern Brazil indicate that they are generalist feeders that employ both ambush predation and wide-foraging strategies.

Their prey consists nearly exclusively of aquatic or semi-aquatic species, including a wide variety of mammals, birds, reptiles, amphibians, fish and eggs.[11] Larger specimens can prey upon larger animals, such as brocket deer, capybaras or peccaries.[4] The prey-to-predator weight ratio is often much higher than for other types of Boidae.[12] Cannibalism has been observed in this species, though it is not clear how often this occurs.[13]

The yellow anaconda has few predators. Juveniles and the occasional adult may be taken by caimans, larger anacondas, jaguars, cougars, some canids such as the crab-eating fox, mustelids, and raptors. The species is also hunted by humans for its skin.[10]

A yellow anaconda in the waterhole, at the Beardsley Zoo, Bridgeport, Connecticut

In captivity, the yellow anaconda has a reputation for being unpredictable and somewhat dangerous to humans, especially when caught from the wild, leading some professionals and keepers to begin efforts at captive-breeding.[2][4] In the United States, the import, transportation and sale of the species across state lines was banned in 2012 in an attempt to prevent the yellow anaconda from becoming an invasive species, in vulnerable natural areas such as the Florida Everglades.[14] The conservation status of the yellow anaconda has not been assessed by the IUCN.

Wikimedia Commons has media related to Eunectes notaeus.

• Eunectes notaeus at the Reptarium.cz Reptile Database. Accessed 4 July 2008.