The bald parrot is a species that lacks any head feathers — apart from some sparse bristles. Endemic to the east-central Amazon, its baldness might be an adaptation for eating fruit without getting its feathers sticky.

The Chacoan peccary was initially described as an extinct species from fossils discovered in 1930. In the early 1970s, a living population was found in an isolated area of Paraguay — in a region known as the Gran Chaco. This species is the largest and rarest of the three living peccaries.

A paradox frog tadpole can grow to be 27 centimetres (11 in) long — the largest tadpole of any frog. It eventually metamorphoses into a shrunken adult frog, only some 7 centimetres (2.7 in) long.

The horned marsupial frog has the largest eggs of any living amphibian. The female carries the eggs in a pouch on her back, each in its own chamber, until they emerge as fully-formed froglets.

The ornate horned frog is also known as a "Pacman frog" and referred to as a “mouth with legs” — and it is, appropriately, quite a glutton. It'll eat any prey that fits in its enormous mouth, from insects to lizards to mice to birds to other frogs. It'll even attempt to consume prey larger than itself.

The torrent duck is highly adapted for hunting within the fast-flowing rivers of the Andes — it kicks with powerful webbed feet, its long claws cling to slippery rocks, and its sleek body allows it to scale waterfalls. Even chicks, soon after hatching, plunge into the dangerous currents.

The large-billed tern uses its disproportionately long and thick beak to catch fish — either by plunge-diving into the water or skimming the surface with its beak as it flies. It has a commensal relationship with the tucuxi river dolphin, which often flushes fish towards the surface while hunting.

The Titicaca water frog lives solely in the depths of Lake Titicaca in the Andes mountains at elevations of 3,810 metres (12,500 feet). Its copious skin folds allow it to breathe — through cutaneous respiration (skin breathing) — at such high altitudes, its lungs are only 1/3 the size they should be.

The Amazon milk frog isn't named for its milky white appearance, instead, its name refers to a poisonous milky substance that it secretes when threatened. It also uses the fluid as "sunscreen" — lathering it over its body to prevent itself from drying out in the sun.