What is the most humane way to kill a cane toad?

http://www.eurekalert.org/pub_releases/2015-05/uos-wit052615.php

Public Release: 26-May-2015
University of Sydney

Like many pests, cane toads are killed in their thousands in Australia every year, especially by community-based 'toad-busting' groups. New research has now revealed the most humane way to do it.

"We need to offer a humane death to the toads - it's not their fault they were brought to Australia 80 years ago - but until now nobody has been sure how to do it," said Professor Rick Shine, from the University of Sydney's School of Biological Sciences.

He is lead author on research showing that a once-popular method, currently outlawed nationally and internationally by animal ethics committees as inhumane, is actually a simple and ethical way to kill a toad. The research by the University of Sydney, Monash University and the University of Wollongong is published today in the journal Biology Open (paper attached).

The researchers implanted small data-loggers in the brains of cane toads to measure any pain responses. They then put the toads into a refrigerator for a few hours, before transferring them to a household freezer. The toads quietly slipped into unconsciousness as they froze, and their brains did not register any evidence of pain during the process.

Professor Shine said: "This procedure was a widespread method for humanely killing amphibians and reptiles for many years until about 20 years ago, but animal ethics committees decided it was inhumane because the animals' toes might freeze while their brains were still warm enough to detect pain. However, our work shows that in cane toads at least, the toad just drifts off into torpor as it cools down, and its brain is no longer functioning by the time its body begins to freeze."

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