The Cane toad (Bufo marinus) is one of the largest amphibians in the world. Females of this species are larger than the males and can be up to nine inches long from nose to rump and can weigh as much as four pounds. Cane toads are native to Central and South America but have also been introduced into Florida, Hawaii, and Northern Australia.
Unfortunately, after their introduction into Australia in an effort to help combat the sugar cane pest problems, the Cane toad earned a bad reputation as an invasive species. Like other toads in the Bufonidae family, the Cane toad possesses glands behind its head that secrete a poison when the toad is being attacked by a predator. This form of protection has allowed the toads to survive and reproduce at startling rates. Another factor for its prolific survival is that it is an opportunistic carnivore that will try to eat just about anything it can catch.
The Cane toad was introduced into Northern Australia from Hawaii in 1935 as a natural way to eradicate the cane beetle from sugarcane crops. It was believed that introducing a opportunistic carnivore was a better idea than to spray the cane crops with pesticides. Sadly, the Cane toad population went from minimal to millions in the last 70 years, due in part to their large appetite for the native Australian fauna and the non-existent predators and competition to stand in their way.
In their native habitats, Cane toads will eat insects and other invertebrates and have to compete with other predatory reptiles, birds and amphibians for their prey. In Australia, the Cane toad has the advantage over the native predators thanks to its poisonous skin and will eat a wider range of prey than what it normally would. This includes other species of toads and frogs, small lizards and even their own young.
Cane toads are not unlike another large species of amphibian in their opportunistic ways. The American Bullfrog (Rana catesbeiana) is well known for stalking its prey in an almost tiger-like manner. Bullfrogs are also known to eat anything they can get into their mouths and are well known for their cannibalistic nature. They will also eat mice, small snakes and lizards, birds, and fish.
The Cane toad should not be blamed for its natural behavior. It was humans who took it from its home and put it on foreign soil and then expected it to be well behaved.
Sources:
http://www.canetoadsinoz.com/index.html
http://animals.nationalgeographic.com/animals/amphibians/cane-toad/
http://www.honoluluzoo.org/cane_toad.htm
Behler, John L. and King, F. Wayne. The Audubon Society Field Guide to North American Reptiles and Amphibians. Syracuse: Knopf, 1979.
