Kev wrote:

I wonder if anybody know anything about rat poison. I have an overseas
development and they get forest rats coming out of the neighbouring
forest and chewing everything in the bungalows and they put down
poison to kill the rats.
Unfortunately the cat eat a dead or dieing rat and died.
Are there any poisons that become inactive once digested by the host.

This is known as 'secondary poisoning'. Unfortunately I think cats
would be more likely to catch a dying rat that was slowed by the poison
than eat a dead one, so a poison that deactivates over time wouldn't be
much use for protecting the cat. The wikipedia article at
http://en.wikipedia.org/wiki/Rodenticide talks about 3 types of poison
in detail, anticoagulants, metal phosphides and calciferols. Chloralose
also seems to be common. Anticoagulants seem to pose the greatest risk
of secondary poisoning, although an antidote is available. Metal
phosphides would be safer if the cat only ate the meat from the rat but
didn't touch the digestive system. I don't know whether this is usual
though. The wikipedia article cites a source that says calciferols are
inherently less toxic to cats, but dogs are still affected. I don't know
if dogs eat rats, since my knowledge of animal predation comes mostly
from cartoons.

Joe