A mutation is a genetic anomaly in a genome. In the aftermath of the Nuclear Apocalypse, prolonged exposure to abnormal conditions such as high radiation on Earth and the Ark resulted in many mutations in living organisms. The extent of the biological changes are yet unknown, except some discernible changes in the observable characteristics and much higher tolerance to radiation. After the Second Nuclear Apocalypse, and the Damocles Event that destroyed the Shallow Valley, the fate of all mutations is unknown, particularly as the Earth eventually regenerated from the damage that was done.
The Two-headed deer is the result of mutation after almost a century of radiation, which caused it to have two heads. It is not hostile, and it is unknown if it uses both heads. It is seen in "Pilot" and in the title sequence of every episode thus far. From the side view, the deer looks like any other regular deer would have prior to the apocalypse. The body is the same in every way to a non-mutated deer; the only difference is the heads. One head is the primary head with most of the features, the other one is the secondary head because it is relatively smaller and shares fewer parts. The primary head has both antlers, one ear, a snout, one regular eye and barely any pink spots. The secondary head has no antlers, one ear, a deformed snout, one eye and many pink spots. Both heads share an eye in the middle.
The Luminous Butterflies are seen in the episode "Earth Skills". They look like ordinary butterflies, other than the fact that they seem to glow in the dark. The butterflies so far have only been seen during the day and do not appear hostile, rather acting like normal butterflies. They appear to group together and form roosts in trees, similar to migrating monarch butterflies.
Shown in the episode "Pilot", river snakes lurk in rivers and attack whatever comes into the river. It is estimated to be 10 feet long and 2 feet wide. It slithers like a snake, but it also swims and bites like a piranha. It can cause minor injuries or fatal ones, depending on how quick their victim is to escape.
In "Blood Must Have Blood (Part 2)", a huge mutated lamprey goes on the hunt during night time. It attacks a boat with Sky People and consumes two of them before leaving. In the episode Red Sky at Morning, Luna mentioned that they fish giant lampreys for consumption.
Two-headed horses are identical to regular horses, only they have two heads. They appear to have a similar mutation as the two-headed deer and potentially many other wildlife.
Humans can also be born with deformities due to radiation. Grounders call people with deformities "Frikdreina" (Trigedasleng). When a child is born with a deformity, Grounders usually leave the infant to die so that "the nature can reclaim them". The deformations can happen in many places, but have only been seen on the head and hand thus far. An example is Zoran, a boy with a disfigured face and Emori, a Grounder with a disfigured hand.
Pauna is a giant gorilla. Lexa referred to Pauna as a Her. In the episode "Survival of the Fittest", Pauna killed Quint and Major Byrne before chasing Lexa, Clarke, and Lexa's bodyguard into her feeding grounds amid the ruins of the National Zoo. Pauna killed Lexa's guard then Lexa and Clarke locked her in one of the rooms. Clarke later said the door would not hold for long after they had gotten away from Pauna. It is unknown if any other giant gorillas exist. Pauna last sighting was at the Zoo, according to Kane's map of Trikru.
Small parasitical worms that burrow their way into human bodies, poisoning their victim and then bursting out of the stomach when they are done consuming the host they infested. We do not know much about parasite worms but they are first encountered in "Shifting Sands". During the Battle for Eden, Octavia Blake decides to weaponize them with the help of Kara Cooper. In "How We Get to Peace," Clarke Griffin and Bellamy Blake conspire with Indra to stop the war by killing Cooper with the worms and making it look like an accident so that they can be destroyed and Octavia will be forced to surrender. The plan initially works with Indra triggering a failsafe gas to put an end to them, but Octavia reveals that she had always intended to use the worms eggs as a weapon, not the worms themselves.
According to Cooper, the worms could not survive the green, habitable environment, implying that they will eventually die from it.
Like the butterflies, some plants on Earth glow in the dark. The plants that glow in the dark are mainly mossy tree bark and bushes. While they glow at night in the first episode, they don't appear to glow in later episodes, indicating a possible inconsistency, or a cycle, meaning that they only glow some nights.
In "Day Trip", psychoactive nuts cause members of the 100 to exhibit unusual and/or irrational behavior and experience one or several psychedelic effects including hallucinations, euphoria (e.g. in the case of Monty), paranoia (e.g. in the case of Jasper). remorse (e.g. in the case of Bellamy), and flashbacks (e.g. in the case of Clarke). The psychedelic effects seem to appear within an hour or so and last a few hours. Lincoln explains that they are called "Jobi Nuts" and that they cause "visions" when they "go bad". While these nuts have not been established as a mutation, as of current day, no hallucinogenic nuts or fungi grow naturally in the area of the US where the 100 is settled, indicating either a mutation or a migration of natural plant species, both of which could be caused by nuclear radiation or a nuclear winter.
The following were affected by the Jobi Nuts:
- Monty Green – looking for the moon and eats a pine cone.
- Jasper Jordan – sees Grounders everywhere.
- Nathan Miller – tripping out.
- Bellamy Blake – guilt over the Culling.
- Clarke Griffin – conversation with her dad.
- Connor – wanted to be the most beautiful broom in a broom closet of brooms.
In Season Four, Jasper Jordan turned the nuts into Jobi tea as a drug for his end of the world party after harvesting some in "God Complex." In "The Other Side," Riley overdosed on the Jobi tea and the rest of the group decided that they would rather commit suicide using an overdose of Jobi tea than spend five years within a bunker. By the time Monty returned, the group was dead or dying in Jasper's case aside from Harper McIntyre who decided to go to the bunker with Monty instead.
In "Ashes to Ashes," Octavia comments that Red Sun toxin is "a hell of a lot stronger than Jobi Nuts."
In "Bitter Harvest", Octavia comes into contact with trees oozing sap that burns her skin while she and Gabriel are hiding from Farm Station scouts. Later, Grounder villagers use the wood from these trees to set a trap for Skaikru, setting piles of the wood on fire with burning arrows to make a poison smoke that kills Monroe and another member of the group sent by Pike to clear the village.
The trees produce a yellow sap that burns the skin on contact. According to Pike, the ash from burning the wood from the trees rendered the land the Skaikru had intended to farm useless.
There are several trees today that have caustic sap and produce toxic smoke, including the Poisonwood Tree (Metopium toxiferum) and the Manchineel Tree (Hippomane mancinella). Both can be found in the United States but they are usually found in more tropical areas. However, the trees seen in "Bitter Harvest" do not appear to be either one of these species, so it is likely that the trees encountered in the show are mutations.
Notes and Trivia
- Bioluminescent butterflies in this series are different from fluorescence butterflies in the real world. Fluorescent butterflies have fluorescent markings on their wings and do not glow in complete darkness like bioluminescent butterflies would.
- Emori and Sienna stated that Frikdreina (mutated humans) were not welcome in clans or villages.
- After the Second Nuclear Apocalypse, and the "Damocles" bomb that destroyed Shallow Valley, the fate of all mutations is unknown, even though the parasitic worms were encountered before by Wonkru. However, according to Kara Cooper's research, the worms could not survive the green, habitable environment, implying that they will eventually die from it as the Earth regenerated itself and becomes more habitable.
- Emori may be the last Frikdreina (mutated human), since the Second Nuclear Apocalypse, and the Damocles Event.