Wildlife
Snakes loom large in the human imagination, from the venomous cobras to the boas and pythons that squeeze their prey to death and swallow it whole. In the UK only the adder is venomous, but elsewhere - such as in Australia - are concentrations of some of the planet's most toxic snakes. Snakes are venomous rather than poisonous as they actively deliver toxins, usually through a bite. Explore below to find video of David Attenborough's close encounter with a spitting cobra and watch sea kraits as they defy the image of snakes as single-minded individualists to go hunting in a group.
Did you know?
The largest snake ever discovered was a Titano boa, it lived 60 million years ago and would have measured 15m (50ft).
Scientific name: Serpentes
Rank: Suborder
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Snake tactics
Snakes use their venom for both attack and defence.
One of Sir David Attenborough's most memorable experiences was a close encounter with a spitting cobra. Protected by a full face visor he quite literally put himself right in the firing line for this sequence. As the snake's welfare was as important as the crew's safety, a captive cobra used to being handled was filmed, though of course the risk posed by the venom was just as high.
Snake evolution
The first snakes probably resembled the flowerpot snake.
The first snakes probably resembled the flowerpot snake.
Sea krait hunt
Unique co-operative hunting behaviour is recorded on one of the world's remotest reefs.
The unique and only recently discovered communal hunting behaviour of this population of sea kraits has never been filmed before and HD brings pristine clarity to the underwater footage. The snakes proved very inquisitive, wrapping themselves round the cameraman's legs. As a result, it was extremely hard to film natural behaviour while being sure to avoid the snakes' potentially lethal bite.
Bat-catching snakes
Thermal imaging and infra-red show how snakes hunts with deadly accuracy in the dark.
Australia's Bat Cleft cave was lit with infra-red so as not to change either the snake's or the bats' behaviour. Two high resolution security cameras equipped with different sized lenses and mounted on a single custom built tripod meant different views could be captured without moving the tripod and disturbing the animals. A thermal imaging camera then illustrated how the snakes detect their prey.
The shading illustrates the diversity of this group - the darker the colour the greater the number of species. Data provided by WWF's Wildfinder.
Discover what these behaviours are and how different plants and animals use them.
Additional data source: Animal Diversity Web
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with many more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads with their highly mobile jaws. To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca.
Living snakes are found on almost every continent (except Antarctica), in the Pacific and Indian Oceans, and on most smaller land masses — exceptions include some large islands, such as Ireland and New Zealand, and many small islands of the Atlantic and central Pacific. More than 20 families are currently recognized, comprising about 500 genera and about 3,400 species. They range in size from the tiny, 10 cm-long thread snake to the Reticulated python of up to 8.7 meters (29 ft) in length. The fossil species Titanoboa cerrejonensis was 15 meters (49 ft) long. Snakes are thought to have evolved from either burrowing or aquatic lizards during the mid-Cretaceous period, and the earliest known fossils date to around 112 Ma ago. The diversity of modern snakes appeared during the Paleocene period (c 66 to 56 Ma ago). The oldest preserved descriptions of snakes can be found in the Brooklyn Papyrus.
Most species are nonvenomous and those that have venom use it primarily to kill and subdue prey rather than for self-defense. Some possess venom potent enough to cause painful injury or death to humans. Nonvenomous snakes either swallow prey alive or kill by constriction.
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Boas and pythons
Colubrid snakes
Cobras, kraits and coral snakes
Sea kraits
Vipers
