By 3 News online staff
A new study shows domestic cats in the US might kill as many as 3.7 billion birds and 20.7 billion rodents each year.
Researchers at the Smithsonian Conservation Biology Institute in Washington looked at previous studies on cat behaviour, estimating each one killed between 30 and 47 birds each year, and between 177 and 299 mammals, in temperate areas. With an estimated cat population of between 114 million and 164 million, and plugging other factors into their equations, this was extrapolated out to 3.7 billion birds and 20.7 billion rodents each year.
Most of the killing was done by strays.
"Unowned cats, as opposed to owned pets, cause the majority of this mortality," says Scott Loss, who led the study.
Cats "are likely the single greatest source of anthropogenic mortality for US birds and mammals".
Here in New Zealand, economist Gareth Morgan earlier this month said cat owners should not replace their pets when they die, and called for cats to be registered, like dogs.
"That little ball of fluff you own is a natural born killer," his Cats To Go website claims.
Mr Morgan, who has come under fire from cat lovers and the SPCA for his views, said he'd rather have lizards than cats on his property.
“If you let him onto my property I want to have the right to trap that cat and get rid of it, because I would rather have the skinks, the geckos, the lizards, the birds anytime over your cat,” he told 3 News.
The researchers tried to figure out how many reptiles cats slaughtered, but came up blank, reports news agency AFP.