Researchers have discovered four new species of octopus in Antarctica with venom that works at sub-zero temperatures.
They hope to analyze the venom to see if it has medical uses, said one of the researchers, Bryan Fry, of the University of Melbourne. Their discovery, during a six-week expedition to Antarctica in 2007, was published in the journal Toxicon.
Experts have long known there were octopuses in Antarctica, but what surprised Fry and his colleagues was the sheer biodiversity and how natural selection changed the way they hunted and the nature of their venom.
The octopuses would drill small holes in large, shelled prey, through which they inject their toxic saliva.
"We found that venom can work at sub-zero temperatures. It was quite remarkable to find how well octopuses have adapted to Antarctic life," Fry said.
There was a great diversity of species, ranging from octopuses that were two inches long to giant ones, he said.
"Evolutionary selection pressures slowly changed their venom, which allowed them to spread into colder and colder waters and eventually spread into super-cold waters," Fry said in a telephone interview on Thursday.
"We want to see what cool and wonderful new venom components we can find out of these venoms that would be useful in drug development," he said.
"Nature has designed a perfect killing weapon ... they have such incredibly accurate activity that there has to be a way to harness that. To tweak it or modify it or just use one little chunk."
Hypertension drugs like ACE inhibitors are structured after snake venom, while certain diabetes drugs are derived from the saliva of the Gila monster, a slow-moving lizard found in the United States and northern Mexico.