Natural History of an Alien, also known as "Anatomy of an Alien" in the US, was an early Discovery Channel show similar to Alien Planet. This show featured various alien ecosystem projects from the Epona Project to Larry Niven's Ringworld. It also featured many notable scientists and science fiction authors such as Jack Cohen , Derek Briggs, Christopher McKay, David Wynn-Williams, Emily Holton, Peter Cattermole, Brian Aldiss, Sil Read, Wolf Read, Edward Smallwood, Adega Zuidema, Steve Hanly, Kevin Warwick and Dougal Dixon .
- Europa Cone Bacteria, orange-gray bacteria that are in huge towers. These towers rise many miles above the ocean floor. Inside these vents, warm water rises, nourishing layer upon layer of bacteria.
- Europa Sea Vent Herbivore, a giant, gray, shark-like swimmer that feeds bacteria in schools with a suction cup-like mouth on an extended, Opabinia-like trunk. These trunk-shaped mouths pierce the vents to suck in vast quantities of Bacteria. These grazers are territorial and like squid on Earth, flash warning glows to drive away rivals. They make a series of dolphin-like cries.
- Europa Sea Vent Carnivore, a predatory, yellow-green, echolocating, streamlined, shark-like swimmer that is built for speed and preys on the Europa Sea Vent Herbivores. Like the Europa Sea Vent Herbivores, the Europa Sea Vent Carnivores also have an Opabinia-like snout to kill Europa Sea Vent Herbivores.
- Pteropede, a gray-green, millipede-like animal from High Gravity Planet with accordion-folding wings. It resembles a dragonfly when it flies. It may be able to take advantage over of the denser air to fly, but high gravity can lead to a bumpy landing. To support its great weight, the creature's eight legs are directly under its body. It breathes through lungs in the tip of its thagomizer-like tail, which is more efficient than the way insects take in air, so the Pteropede is able to pump oxygen through its large, heavy body. To grow, the Pteropede must enter the water. It is only in the buoyancy of water, where gravity is little effect, that the Pteropede can shed its skin and increase in size. Once the new skin is hardened, the Pteropede can return to the demanding heavy gravity environment on land.
- Sputnik Bug, a small, blue, Eoarthropleura-like animal from High Gravity Planet. It has spines to protect it from a dangerous fall in the high gravity. Whenever it does fall, it immediately rolls up in a ball shape to keep its spines on the outside.
- Splatter Bug, a small, brown, Eurypterid-like Animal from High Gravity Planet. It sadly has nothing to protect its soft body. It's an evolutionary dead end.
- Helliconian Tree, a strange-looking tree with a cooling tower-shaped trunk and branches on the very top with thin in width leaves, making the branch look like a moth antenna during the short summers. Like deciduous trees on Earth, the Helliconian Tree turns dormant during snow-filled winters. It sheds its leaves but its branches curl up and go inside the Tree. The Tree then shields its top with an ice-like cap it grows.
- Sulfurian Balloon Plant, a tall, orange plant that lives off of sunlight. They are like giant balloons, anchored to the ground and being pulled up by the gas that is inside of their flattish, pizza-like tops. They are like kelp on Earth. Babies sprout from the sides of the parent plant and eventually break off, becoming an independent adult.
- Parachute Worm, a whitish-gray, earthworm-like animal from Sulfuria that lives off the gas of the Sulfurian Balloon Plant by sucking it out. Newly-born larvae resemble twigs with two umbrella-like extensions. Larvae are born live as the mother is feeding. After a little while, the young depart from their mothers and use the umbrella-like extensions to parachute down gently through the murk of the atmosphere to the planet floor and shed their umbrella extensions. After falling into water and shedding, the young Parachute Worms feed on the nutritious roots of the Sulfurian Balloon Plants. When they have fattened up, the adults make their epic journey back up the stalks to mate. The Parachute Worm is a perpetual migrant. Its lifecycle is a response to this extreme environment.
- Epona Pagoda Tree, a thin-looking, green Tree with large, disk-shaped leaves surrounding it. The reason why the leaves are so huge is because they need to get as much carbon dioxide as possible. They have a remarkable ability of movement. If a herbivore comes to nibble on them, they are able to fold back their branches.
- Spring Croc, a green, hopping, two-legged, predatory, Venus Flytrap-like animal. It is the major predator on Epona. It lies in wait for its prey (usually partially submerged). It is extremely vicious. It is a lot like the Earth shark, it mostly focuses on eating. It does not need to be intelligent, it just has to be quiet.
- Uther, a brownish-gray flyer from Epona resembling a cross between a Sharovipteryx and a Pterosaur. They are descended from flying fish-like ancestors. They started out in their avian-like lifestyle hunting Salacopods (small, amphibian-like creatures). They later on graduated to larger carcasses to feed on. Then they started to become predators themselves. In order to fly, they have a boost, which is a combination of hydrogen peroxide and ethanol, which hyper-oxygenates their blood. It allows them incredible stamina.
- Curlywhorl, an arboreal, purplish-red, centipede-iguana-like animal from Green World that came from aquatic, sea star-like animals (like all the other inhabitants of Green World did).
- Pud, a small, green, three-eyed, weevil-like animal from Green World's equator. There are thousands of species across the planet. They are comparable to beetles of Earth in variety and niche. A Pud has six limbs, only four of which are symmetrically paired. Five are used for grasping and one is used for movement. This gives the Pud a hopping movement. They are often in groups, foraging for food in the undergrowth. They scavenge on fallen fruit. They have many predators and can sense danger coming with their three sensitive, leaf-like antennae. The Pud portrayed in the show make a series of high-pitched chirps and hoots.
- Armored Kwank, a large, redish-brown animal from Green World with a turtle-like shell on its back. It is presented as the anteater of Green World, often hunting Puds.
- Unidentified ray-like creature from Europa, apparently a filter feeder but only shown at the end of the Europa clip, not described.
- Unidentified Large, Lobster-Like Predator, an inhabitant of Green World that sometimes attacks and eats Armored Kwanks. Only shown in the form of its shadow.
- Unidentified Intelligent, Green Alien, a yellow-eyed, green-skinned sapient being from an unknown world. A female reveals herself as the narrator at the end of the program.
The viewer is in an intergalactic spaceship named the SS Attenborough run by a small green alien. The Attenborough visits locations real and imaginary.
Earth during the Cambrian.
Mars is discussed primarily as bearing bacteria.
They visit asteroids and talk about the possibility of panspermia seeding solar system with life.
Several creatures potentially living around Europan hot springs are briefly glimpsed.
High Gravity Planet
After some discussion of what life might be like on a low-gravity planet, the ship visits a high gravity planet. they encounter many insect-like aliens who have adapted to 1.5 times Earth's gravity. Though high gravity might make flight difficult, on this planet the denser atmosphere compensates.
Surface Gravity: 145% of Earth
Atmospheric Pressure: 15 times Earth's
They visit the science fiction world of "Helliconia" which was created by Brian Aldiss. It's a binary system and they show how life can adapt to having two suns.
They visit the science fiction world of "Sulfuria" which was created by Dougal Dixon. It is a sulfur rich world that is similar to Jupiter's moon Io.
They visit Epona, an imaginary ecosystem created by a group of scientists and science fiction writers. On this elaborate ecosystem are species such as "Pagoda Tree", "Spring Croc" and "Uther".
They visit the science fiction world of Green World which was created by Dougal Dixon . It is an Earth-like planet filled with lush rainforests. Some of the more notable species include the "Curlywhorl", "Pud" and "Armored Kwank", all derived from starfish-like ancestors.
The ship encounters an artificial lifeforms from a robotic cube ship. It uses solar panels to gather energy and mines asteroids to get resources to grow. It even sends down a probe to "Green World" explore it. One such probe looked like a metal centipede in appearance.