Happy Tuesday, everyone!
Some of you may remember that I was set a challenge by a friend of mine to write a scientific article about Gremlins; specifically, the mischievous critters from the 1984 film. Surprisingly, there aren’t all that many scientific papers written about Gremlins, so I had to find a different angle. I got to thinking, and wondered, just how realistic are these creatures? How many elements of their physiology and life cycle are similar to real animals? In a never-ending quest for knowledge (and payment of cupcakes for my troubles, Saz?) I’ve come up with some answers to these questions.
As this was turning into quite a long post, covering a fairly large number of animals and studies, I decided to go all Peter Jackson on it and turn it into a trilogy of posts. Parts 2 and 3 will be posted later this week. Enjoy!
We’ll start with a bit of background knowledge for those of you who have never seen the Gremlins movies. The titular monsters start off life as cute, furry little critters called Mogwai, which come with three rules for anyone looking to raise one as a pet (one of which will be covered in each part of this post):
1) Never feed them after midnight:
If a Mogwai is fed after midnight, it will metamorphose inside a cocoon and emerge as a Gremlin – a mischievous and dangerous monster, larger than a Mogwai and reptilian in appearance.
2) Never expose them to bright light:
Bright light scares Mogwai and Gremlins alike, whilst sunlight kills them.
3) Never get them wet:
If a Mogwai or Gremlin gets wet then it will spontaneously spawn offspring, which pop out of its back.
Let’s take a look at Rule 1. Metamorphosis is a fairly common phenomenon in nature. It is essentially the rapid physical development of an organism after its birth, often to allow it to change to meet the requirements of the different lifestyle that it will lead as an adult. For example, the infants (or larvae) of most amphibians are adapted to survive in water, whereas they will need to be suited to land as adults to allow them to leave the water in which they were born. Members of several groups of organisms metamorphose as part of their life cycles – most notably amphibians (as mentioned) and the majority of insects, but also some fish.
The form of metamorphosis seen in amphibians and fish involves rapid changes whilst the animal remains active. The more obvious physical changes are accompanied by changes in biochemical and neural pathways, as pathways needed by the adult replace those that were necessary for the larval body. A good example of such a process is the change of a tadpole to a frog or toad. In just one day (in some species) a tadpole’s gills are replaced by lungs, a jaw replaces its tiny mouth and it develops legs. Interestingly, its eyes move from the sides of its head to the front, indicating a change from prey to predator – tadpoles need to see a wider angle to look out for prey, whereas frogs need good 3D vision to attack prey they see in front of them. However, whilst a Mogwai undergoes a drastic physical change, it does so inside a cocoon. This is the property of a different type of metamorphosis altogether, as we will now see.
Metamorphoses in insects can be divided into 2 categories: ‘complete’ and ‘partial’, or ‘holometabolous’ and ‘hemimetabolous’, respectively. Partial metamorphosis involves changes spread over multiple stages, generally allowing gradual growth of the insect and development of organs, whilst the creature is active. As the immature insect (at this point, known as a ‘nymph’) grows, it sheds its outer covering of cells, called the ‘cuticle’. Each of these ‘moults’ reveals increasingly mature structures required by the adult, including sexual organs, until the insect is fully-grown
Complete metamorphosis, on the other hand, involves a single, drastic change, much more akin to that of a Mogwai. The infants in this process are called ‘larvae’. Don’t ask why some insects have larvae and some have nymphs – I swear it’s primarily done to confuse people! Anyway, this process is very similar to partial metamorphosis up until the last moult. At this stage, the larva wraps itself in a protective cocoon, becoming a ‘pupa’. Whilst inactive inside this casing, many of the tissues that made up the larva are broken down and replaced by adult tissues. This allows the organism to undergo massive changes so that, when it emerges as an adult, it can look markedly different in appearance to the larvae. The most obvious example of this is the change a caterpillar undergoes to become a butterfly.
Given this information, it is most likely that Mogwai are depicted as undergoing some kind of ‘complete’ metamorphosis. However, Mogwai appear to be mammalian – they are warm-blooded and hairy – and no mammals metamorphose. Instead, mammals develop and grow outside of the womb. So, whilst metamorphosis is a perfectly realistic notion for a creature’s development, it couldn’t really apply to a Mogwai. It certainly couldn’t explain how a mammalian Mogwai could transform into something, which is ostensibly reptilian. I suppose you could argue that Gremlins are mammals with alopecia and bad skin and that they really need to moisturise…but you probably shouldn’t.
Then we have the part about feeding them after midnight. As far as I can tell, there are no animals in Nature in which eating at a certain time of day can trigger metamorphosis! Metamorphosis is under hormonal control in all living creatures. Of course, not all organisms are controlled by the same hormones and certain changes within an animal may take longer or require higher or lower concentrations of hormones than others. For example, reduction of a tadpole’s tail takes several days longer than generation of the adult body parts. That said, ultimately, like humans, all animals are slaves to their hormones!
In conclusion, I’m afraid to say that Mogwai metamorphosing into Gremlins by eating after midnight is….not scientifically realistic. Sorry folks!
That’s all for Part 1. Remember, Part 2 will go up in a few days’ time. See you then!