Season 1: Episode 8- The Gremlins (Gremlins- 1984)

We kick down the kitchen door and go to bloody war with the Mogwai, from 1984’s Christmas classic Gremlins. Dave gives China tips for invasion, Sam says the word ‘tarsier’ too fucking much and Adam can’t resist showing off how much Mandarin he doesn’t know.

5:52 – History of the Gremlins
18:02 – Movie Any Good?
21:40 – Physiology of a Mogwai
44:11 – Ecology of a Mogwai
1:02:32 – The Gremlins vs. Gollum

Film: Gremlins [1984]
Production Company: Warner Bros.
Distributed By: Warner Bros.
Monster: Mogwai/Gremlins
Featuring: Sam, Adam, David
Rating: Mature (for some offensive language and adult themes)


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In order to best explore the physiology of the Mogwai/Gremlins, it is necessary to divide the species. By that, I mean that we should discuss the Mogwai and Gremlins’ physiology separately. We will try and focus primarily on three interesting subjects with each.


As a general overview, the Mogwai are 1 foot (30-40 cm) in height. They have a generally primate appearance, so we will treat them as a having a similar metabolism and internal processes to other small primate (ex: small gibbon). They are incredibly, and unrealistically intelligent. They have large eyes and an almost neo-nate appearance, considered by many human societies to be “cute.” They have large ears and seem to be quite sound sensitive, reacting to sounds like bells in an exaggerated manner. Their dentition appears to be made up of mostly incisors suggesting a primarily herbivorous diet, but some are seen consuming meat in the film. They have three digits on each hand and humanoid/primate looking feet. They sing when happy and seem to be able to communicate in a few different languages. They are believed to be originally of Chinese origin. The primary topics I would like to discuss with the Mogwai are their reaction when exposed to sunlight, their reaction when exposed to water, and their transformation after midnight.


Within the film, the Mogwai are seen to be hurt by sunlight and hide when exposed. Following an exposure in the film, we can see that Gizmo is mildly burned. I chose to focus on the Mogwai reaction to sunlight (a mild burn) rather than the frankly impossible/unrealistic Gremlin reaction (disintegration).

UV Genetic Disease
The easier way to try and explain the Gremlin’s reaction to sunlight is in a similar manner to what was discussed with the Trolls a few episodes back. There are dermal diseases seen within humans that other primate species could theoretically take on.

The first example is Xeroderma pigmentosum, an autosomal recessive genetic disorder. Affected humans have a decreased ability to repair DNA from damage like that cause by ultraviolet (UV) light. Symptoms can include severe sunburn following only a few minutes. The other disease example is Solar Urticaria. Affected humans develop hives in covered and uncovered areas when exposed to varying degrees of sunlight. The reaction is believed to be histamine based.

Final Thoughts
Based on my research, it is likely that the Mogwai would have some form shared of  genetic disorder like a Solar Urticaria or Allergy. Unwanted exposure would cause them to develop hives and dermal damage. Potentially, this reaction would be worse in the Gremlins because their skin would be less protected by fur. However, sunlight exposure would not be so severe to cause the disintegrating reaction seen within the film.


Within the film, when Gizmo is exposed to water we see a painful reaction and the development of multiple cysts on his back. These cysts quickly fall shoot away from the skin and rapidly develop into fully developed Mogwais in a matter of seconds.

In order to try and make this mechanism work, I had to put together a few different diseases and physiological mechanisms.

Reaction To Water
Some species do have extreme reactions when exposed to water. Within humans, Aquagenic Urticaria is a unique genetic condition in which exposure to water can lead to the generation of hives. The mechanism of action remains unknown.

Encysted Offspring (Brine Shrimp)
Some species can protect their offspring from dangerous environmental conditions by dehydrating them. These eggs or cysts can stay dormant until exposed to water, when metabolic processes resume and the offspring are born. We have discussed these mechanism previously in the “Quiets” episode.

Immature Offspring Production (Marsupials)
Some marsupials like Kangaroos produce immature offspring. Eggs are fertilized internally but the neonates are born in a state that cannot survive with exposure in the real world. The offspring are blind, hairless, and only a few centimetres long. Their muscles are underdeveloped and they use their feeble forelimbs to climb their way along their mother’s fur to a pouch on her abdomen. Once in the pouch, it fastens onto one of the four teats and starts to feed. It will remain there until it is developed enough to start forays into the real world.

Final Thoughts
A method that the Mogwai could utilize to produce a reaction to water similar to what is seen in the film would be deposition of offspring under their skin or within fur. Most likely, the offspring would be contained in pouches similar to what is seen in kangaroos. They would be immature, and attached to teats. Upon exposure to water, the pouches would begin to break away, revealing the offspring and allowing them access to the outside world. The offspring would not shoot off or grow rapidly. However, they could fall off Gizmo and continue their development in the outside world.

It should be noted that replication would not produce evil versions, and Gizmo would lose significant muscle mass when dropping offspring.


Within the film, the Mogwai are seen to develop into Gremlins when fed after midnight. Feeding causes the Mogwai to form a chrysalis and after a day or so, the creatures emerge as gremlins.

Chrysalis In Nature
Within nature, the best example of a chrysalis based transformation is the caterpillar to butterfly transition. Caterpillars consume a large amount of material in their early stage, preparing for their transformation. When ready, they form a cocoon or chrysalis to protect themselves. Within this structure, released enzymes dissolve their tissues and still not completely known mechanisms allow for their bodies to be reshaped into new forms. After weeks, a butterfly will emerge.

Final Thoughts
As a prelude before the discussion, very specific time frames as a trigger is not a good system for any biological transformation. Time, at least as how we usually discuss it, is an artificial human construct. Yes it is true that changes in season at certain times of year can trigger biological events, but these are processes that take place over days to weeks. They are not specific to the hour of a day. There is no way to build a biological mechanism that would respond to midnight.

It is more likely that the Mogwai’s transformation trigger would have more to do with the quantity or type of food consumed. Within the film, transformation is seen to occur after the consumption of large amount of a large amount of chicken wings and a sandwich. It is possible that the massive quantity consumed all at one is what triggers the transformation (although the sandwich seems small). It is also possible that it is consumption of meat that triggers the change as the Mogwai are not seen eating meat previously.

As for the transformation itself, a chrysalis would be a very difficult means of transformation for a mammal. Bone, muscle, skin would need to be broken down. It is more likely that the type of chrysalis formed would not be like what is traditionally seen in insects. Instead, they may secrete some form of temporary shell or moult, inside of which they would experience increased normal metabolic aging/development. In otherwise, they would create a structure to allow them to grow at a rapid rate, potentially aid by some formed of secreted growth medium.


The Gremlins are approximately three feet in height. They have primarily carnivorous dentition/teeth and seem capable of eating a wide variety of substances, ranging from meat to glass. They have three digits on each hands that end in razor sharp claws. Their eyes are different from those seen in Mogwai. They are smaller, slitter, and have an orange to red iris color. They are almost completely hairless and their skin appears to be generally thickened. They are far more resistant to damage than the Mogwai. They are very fast, incredibly destructive and have an intelligence that is off the charts.

The primary areas that will be focused on in our discussion is eye color/design, skin design, and replication with water. I will also be briefly touching on their talon feet transformation and gastrointestinal system.


Following transformation, the eyes of the Mogwai (circular grown iris) change to a slitted confirmation with a orange-red color. This transformation might indicate a change to a semi-nocturnal hunting lifestyle.

Final Thoughts
Owls have different eye colors based on the time of day that they hunt during. Owls that hunt during the day have a yellow iris and those that hunt during the night usually have a dark colored iris. Owls that hunt at dusk or dawn, have a red to orange iris. This would fit with the Gremlins hunting pattern. Interestingly, the exact reason for different eye colors for different hunting times remains not completely understood.

As for the adoption of a slitted pupil, this fits with night survival. A slitted pupil allows for a huge change between constricted and dilated states compared with a circular pupil. This in turn allows for much more precise control of light reaching the retina, and more effective vision at night. As a result, it is assumed that the Gremlin iris transformation is to allow for more effective night hunting.


The Gremlins transformation from the Mogwai seems to allow the skin to become thickened and hardened. They also seem to lose their hair. The reason for this could be for a couple of reasons. The first of which might be to allow for dense epidermal tissue. The palms of your hands are thickened and undergo a process called hyperkeratinization. As a result they are more resistant to damage, but as a result do not allow for the formation of hair follicles Another reason might be that their hair has not grown in yet following their transformation into Gremlins. The last reason might be that their metabolism is to rapid to allow for hair growth, as they maintain to warm and need to be able to dissipate heat.


Following the transformation from Mogwai to Gremlin, the feet take on a format more similar to a raptor (bird of prey) or chicken. Their skin seems to become more reptilian in appearance. This mechanism is unlikely to something that could be accomplished through the chrysalis process as it would require a major change in body plan from the other features seen between Mogwai and Gremlin.


The Gremlins appear to be able to eat everything in their path. The are seen continuously eating subjects ranging from glass to hard plastics. In order to accomplish this they would need a more acidic stomach and likely features like gastroliths (stomach rocks) like discussed within the Troll episode.


Shelley WB, Rawnsley HM. Aquagenic Urticaria: Contact Sensitivity Reaction to Water. JAMA. 1964;189(12):895–898. doi:10.1001/jama.1964.03070120017003.

Breed WG (1996) Egg maturation and fertilization in marsupials. Reproduction, Fertility and Development 8, 617-643.

Lowe Tristan, Garwood Russell J., Simonsen Thomas J., Bradley Robert S. and Withers Philip J. Metamorphosis revealed: time-lapse three-dimensional imaging inside a living chrysalis10J. R. Soc. Interface.


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