CANBERRA, Australia - Tourist Sandra Bell was poised to photograph a sedate scene of two crocodiles sunning themselves at the edge of an Australian waterhole when the picture unexpectedly exploded into violence.

Bell was startled but managed to snap around 20 graphic photos as a 5-metre estuarine croc killed and devoured a far lighter 2.5-metre croc over 15 minutes.

鈥淚t was super amazing but pretty terrifying as well,鈥 Bell said on Friday. 鈥淚t looked like it was pretty much dead pretty quickly.鈥

The extraordinary pictures were taken on Oct. 26 at Catfish Waterhole in the Rinyirru National Park, where Bell had been camping with her 14-year-old son in north Queensland state. The mother and son, from Shark Bay in Western Australia, were on a yearlong vacation driving around the country.

Without warning, the large croc suddenly clamped its jaws around the other's tail and flung the smaller croc's entire body repeatedly through the air and into the water.

Although Bell was 30 metres away from the action on the opposite bank, she found herself backing away through fear as she continued to take photos.

鈥淚 had no idea how forceful and powerful it was,鈥 she said. 鈥淭here were waves and splashes going everywhere and you could hear the little one getting thumped into the water.鈥

Crocodile expert Grahame Webb said cannibalism was common among crocs although humans rarely witness such attacks in the Australian wilderness.

While birds and fish preyed on hatchlings, the only predator a larger croc feared was another croc.

鈥淥nce a croc gets to 1-to-2 years old, its survival depends on how many big crocs are around,鈥 Webb said.

Webb said the violent throwing of the smaller croc was an attempt to tear away body parts to swallow.