As the evening sky deepened from violet to black, fireflies and Halloween Crabs were not the only nocturnal creatures to emerge on the lawns surrounding Las Caletas Lodge in the Pacific lowlands of Costa Rica, Cane Toads (Bufo marinus) were also regular evening visitors there.

Cane Toads are opportunistic predators and will eat whatever mouth-size prey they can capture. Although Cane Toads are native to Central and South America, these voracious toads have been introduced to other places around the World, such as to Australia, in ill-considered attempts to control crop pests.

These huge toads can afford to be rather calm and nonchalant as they hop across the grass because they are quite poisonous. The large bulge behind the eye is a poison gland.

Poison is expelled from this gland into the mouth of a predator if the toad is picked up or bitten, and this poison can be fatal unless the mouth is thoroughly flushed with water.

Knowing that they are protected by their poison glands, these toads let me approach them quite closely. While they don't seem too bothered by the presence of humans, the lighter Cane Toad below assumed this rather strange, upright posture when the first, more reddish Cane Toad approached it too closely.

This toad's posture looked hostile to me, but I don't understand toad body language, so I'm not positive what it was trying to communicate to the other Cane Toad.