Largest snake ever

Until very recently, the largest snake ever known to have lived is Titanoboa cerrejonensis, a prehistoric species of boa known from the fossils of 28 specimens found in the coal mines of Cerrejón in La Guajira, Colombia. Their discovery had been made by an international scientific expedition led by Florida University vertebrate palaeontologist Dr Jonathan Bloch and was formally announced in February 2009 in the journal Nature. The fossils revealed that Titanoboa, which lived 58–60 million years ago during the Palaeocene Epoch, reached a maximum length of 12–15 m (39–49 ft), measured approximately 1 m (3 ft 2 in) across at the thickest portion of its body, and weighed roughly 1,135 kg (2,500 lb). In April 2024, however, it emerged that Vasuki indicus, a fossil species of madtsoiid snake known from 27 vertebrae (some still articulated) unearthed in the Indian state of Gujarat during 2005, is estimated to have measured 10.9–15.2 m (35 ft 9 in–49 ft 10 in) long, meaning it may have rivalled or even exceeded Titanoboa. It lived 47 million years ago, during the mid-Eocene Epoch. The findings about Vasuki were published in Scientific Reports on 18 April 2024.

Titanoboa was a true boa, and was most closely related to the boas of Madagascar and the Pacific. Prior to its discovery, the world's largest-ever snake was believed to have been Gigantophis garstini, a madtsoiid, which was estimated to have measured 6.6–7.2 m (21 ft 7 in–23 ft 7 in) long. It lived around 40 million years ago, during the Eocene Epoch, inhabiting the region occupied today by Egypt and Algeria. Vasuki was also a madtsoiid, a widely distributed but nowadays wholly extinct taxonomic family of snakes whose fossil record extends from the Upper Cretaceous to the Late Pleistocene, and zoogeographically encompasses southern Europe, Africa, India, South America and Australia. The most recently surviving species were those inhabiting Australia during the Pleistocene. Madtsoiids may have been constrictors, like pythons and boas.

Both of these extinct snake species would dwarf today's biggest snakes. The longest living species of snake is the reticulated python (Malayopython reticulatus) of south-east Asia, Indonesia and the Philippines, which regularly exceeds 6.25 m (20 ft 6 in); the record length is 10 m (32 ft 9.5 in) for a specimen shot in Celebes (now Sulawesi), Indonesia, in 1912. The heaviest living species of snake, meanwhile, is the green anaconda (now recognized as two species), native to wetlands and slow-moving rivers of tropical South America and Trinidad. In February 2024, the long-recognized single species of this large constrictor was split into two based on genetic and geographic differences: the southern green anaconda (Eunectes murinus) and the northern green anaconda (Eunectes akayima). Fully grown, females of both species obtain a typical weight of between 30 and 70 kg (65–155 lb), measuring 3–5 m (9 ft 10 in–16 ft 4 in) from head to tail. Occasionally much larger specimens (almost certainly all females) have been reported, reaching between 7–8 m (22–26 ft) long with an estimated weight in excess of 300 kg (660 lb); it’s likely that the heftiest examples are either pregnant or have just consumed a large meal.