Toads

Like most creatures of wetlands and other relatively specialized habitats, some species of toads have suffered large population declines through losses of their natural habitats. This has been an especially important problem for species whose original distribution was quite restricted, for example, the rare and endangered Houston toad (Bufo houstonensis).

One species of toad has become an important pest in some parts of the world. The cane or marine toad (Bufo marinus) is a large species, reaching a body length of 11.5 in (29 cm) and weighing as much as 2 lb (1 kg). The cane toad is native to parts of Central America, but it has been introduced to many other subtropical and tropical regions in misguided attempts to achieve a measure of biological control over some insects that are agricultural pests.

The cane toad now occurs in Australia, New Guinea, Florida, and many other places, especially tropical islands. Cane toads have become serious pests in many of their introduced habitats, in part because of great damages that are caused to the breeding populations of large species of birds, lizards, and other predators, including domestic cats and dogs. These animals are often naive to the dangers of attempting to eat the poisonous cane toad, and they can therefore be killed in large numbers. The parotoid glands of the cane toad can emit a large quantity of a frothy substance containing noxious chemicals that block neurotransmission, and can lead to death by paralysis.

In small doses, the cane toad secretions can cause a hallucinogenic effect in humans, and people are known to lick the parotoid glands of cane toads in order to achieve this effect. However, it is easy to receive too large a dose of this chemical, and people have been made significantly sick, and have even died, while trying to get high in this manner.