Titanoboa (the Whitney Houston of snakes)

 Sometime between 1690 - 1700 the term 'snake in the grass' was first used to describe a treacherous person, especially one who feigns friendship. Fast forward 300 or so years and I'm standing there in my living room, being accused by my mentally ill housemate of the same thing. Idioms and arguments aside, the homo sapien's fear and revilement of snakes has a long history, but maybe those Ophidiophobes should count themselves lucky that they don't live in the Paleocene epoch 58 million years ago  - cover your eyes, we're about to go big.

 Immediately following Cretaceous-Paleogene extinction event which closed the curtains on all non-avian dinosaurs (and a lot of the supporting actors from other species) much of the remaining life on Earth underwent a process of rapid diversification called 'adaptive radiation.' Birds, fish, snakes and mammals diversified into many various forms that we recognise today - horses, whales, iguanas, tunas, eels et al. Mammals would obviously go on to great things but recent fossil evidence in Colombia shows between 60-58 million years ago reptiles and snakes near the Equator grew to gigantic sizes due to extreme climate conditions. Enter, Titanoboa:

Titanboa is the largest species of snake ever discovered, and fossil disocveries in the Cerrejon Formation in La Guajira, Colombia, show that these bad boys grew up to 14.5 meters/48 feet long. Quite remarkably for a snake fossil finding, a Titanboa skull was recovered in the dig, as well as fossils from other monstrously large species, such as the Carbonemys, which is the largest turtle ever discovered, with a shell that measured 5.8 feet long! Imagine getting to spend the day in hanging out in a Paeleocene equatorial South American swamp - I don't know about you, but I'm packing pepper spray in my purse.

Titanboa spent most of its time underwater to support its massive frame, and would chow down on crocodiles and large fish in the few times it ate. Much like snakes today, and Whitney Houston in the early 1990s, the Titanboa could unlock its jaw to slay its prey.

 In 2012, a life sized statue was on show in New York's Grand Central:

The findings of Titanboa and Carbonemys tell us that equatorial South America recovered fairly quickly after the Cretaceous-Paleogene extinction. The higher levels of carbon dioxide in the atmosphere and higher temperatures also tell us that many animals and plants are able to cope with extreme tropical climates -  which is just as well considering the alarming global warming rate we are experiencing.

Ophidiophobes - you can open your eyes now.

Sarcosuchus ('flesh crocodile')

Sarcosuchus was ridiculous. Growing up to 39 feet long and weighing 8 tonnes, sarcosuchus make modern crocodiles look positively Toys 'R' Us by comparison.  For a fun juxtaposition, here's what a sarcosuchus head would look like stood next to a modern man in an Hawaiian shirt:

Our understanding of this true giant started in 1964, when a nearly complete skull was found in Niger, Africa. To make room for its 132 teeth, the head of the sarcosuchus was 6 foot alone!

Sarcosuchus lived 112 million years ago, in the mid-Cretaceous period of the Mesozoic era, and displayed a lot of the features and characteristics of their crocodilian descendants today. The sarcosuchus could not 'death roll' like modern crocodiles do, but had a bite that was so powerful that it didn't need to perform such acrobatics to prepare its meal. Such was its size that its only potential for competition came from the 49-foot dinosaur Spinosaurus, one of the fiercest and largest predators this planet has ever seen (Spinosaurus has a star turn in Jurassic Park III, if you remember.)

Without knowing who would win in a sarcosuchus vs spinosaurus fight, what can be said with certainty is that both of these creatures were unable to use their awesome statures to survive the changing climate towards the end of the Cretaceous period. As the Earth's climate became drier, neither could adapt from their reliance of an aquatic habitat. Both went extinct roughly 90 million years ago, a good deal of time before the Cretaceous-Paleogene mass extinction came for pretty much every other living thing 25 million years later.

PS: Here's Nigel Marvin re-enacting what a human-sarcosuchus encounter might play out like. I love you, Nigel Marvin.