Mongoose are small carnivores native to southern Eurasia and mainland Africa. There about 34 different species. Six of which are native to Madagascar. They are an introduced and invasive species in the Caribbean and Hawaiian islands, where they are decimating native bird populations. They are 9.4-22.8″ in length, excluding the tail. The mongoose is immune to snake venom due to the fact that they have receptors for acetylcholine that, like the receptors in snakes, are shaped so that it is impossible for snake neurotoxin venom to attach to them. At some point in history, they were introduced to the Hawaiian Islands to control a non-existant snake population (Don’t ask. I have no idea.). Since then, they run rampant, an invasive alien species which decimates the native bird population by eating their eggs.