The Science of Ant Man

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The Ant Man movie doesn’t claim to be scientifically accurate (and it isn’t), but it does include a lot of “science”. And most importantly, the film is wrong in some really interesting ways. So read on for a critical appraisal of the science of Ant Man, from the perspective of an ant biologist (ex).

[Spoiler Alert] If you haven’t watched Ant Man, you probably shouldn’t read on. Not least because it won’t make a great deal of sense, but because it probably contains what you might consider to be spoilers. Which again, won’t make a great deal of sense.

So, I finally watched Ant Man. A little late, since I’m an ant biologist by training, but it was exactly that which put me off. Going in, I wasn’t holding out much hope that Hollywood would have given ants a fair representation.

I was pleasantly surprised. Yes, Ant Man is rife with scientific inaccuracy, some minor, some more crippling, but it is clear they at least tried to do their research. Moreover, the failures of the film raise many interesting questions about what science could be possible, from high-density fight scenes to mind-controlled insects. So, I thought it worthy of a blog post reviewing the often tenuous, but always entertaining, science of Ant Man.

An extremely dense film

AntMan_003
The first and most obvious issue with the film is the basic premise itself – that you could shrink a human, or any other object, to the size of an insect by reducing the distance between the atoms. Since I’m not a physicist, I won’t cover this in much detail, but suffice to say it sounds pretty unlikely that it would work. See, shrinking your size would make you super strong, and in many ways the film gives an accurate portrayal of how a miniaturised soldier might experience the world. Except for one big problem. Density.

If you shrink someone down by reducing the space between the atoms, the shrunken person (or any other object) would still contain all the matter present in their original, full-sized version, but would occupy a millionth of the volume. Standing no more than 2cm high, Ant Man would still weigh about 80kg, making him incredibly dense.

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I wanted to see just how dense, so I did a little bit of very rough maths.

Let’s assume that Paul Rudd is a roughly average-sized man – 1.7m tall, 0.35 m wide and 0.15 m deep, weighing about 80kg. This gives him a volume of 0.089m3, and an approximate density of 0.9g / cm3. This is roughly in line with other estimates of human density – most human tissues weigh in at about 1g / cm3.

If we shrink him down to 1.7cm tall (those bullet ants are about 3cm long, so this seems roughly OK), then his volume is now 0.089 cm3, but weighing 80kg, poor Ant Man has a density of 896358.54 g / cm3!

For comparison, the density of Lead is about 11g / cm3, and the densest element on Earth, called Osmium, is only 22g / cm3. Ant Man would be over 40,000 times denser than this.

It seems hard to believe that such an absurd density wouldn’t have some pretty serious effects on the human body. Blood is normally around 1.06 g / cm3; could a tiny heart and fragile arteries cope with blood 40,000 times the normal pressure? At that density, neurones would stop firing, the heart would stop pumping, and Ant Man would be dead in an instant. I imagine.

Actually, it would probably look an awful lot like that pink goo.

AntMan_005The same issue would work in reverse for everything that is made giant later in the film (the giant ants, particularly, but see here for a longer explanation of why giant ants wouldn’t work); they would be huge but incredibly light. That Thomas the Tank Engine train certainly wouldn’t have crushed the house.

The biology of Ant Man

But, lets get back to the biology. From a superficial look at Ant Man, it seems as though the researchers really put the effort in – they include three different species of Ant (with latin names!) and explain the differences between them. But unfortunately, the ant facts they present seem to come from little more than a quick scan-read of Wikipedia.

The three species of ant used in the film were the bullet ant (Paraponera clavata; related to my PhD study species, Dinoponera quadriceps), the black carpenter ant (Camponotus pennsylvanicus) and the longhorn crazy ant (Paratrechina longicornis).

They accurately explain that Paraponera is a formidable foe, their sting ranked highest on the Schmidt pain index and described as “pure, intense, brilliant pain”. In fact, the movie doesn’t really do their sting justice – appearing to be a mild annoyance rather than searing pain. Still, bullet ants may well get the fairest representation of any ant featured in the movie.

A issue of gender

The major ant players in the film are carpenter ants, and one of them even gets a named role! Ant-ony provides airborne transportation for Ant Man. Of course, the fact that the only named ant in the film is a male is rather disappointing, given than ant workers are always female, and males play only a small part in the colony life cycle of an ant. Although it has never been accurately portrayed in pop culture (*cough* Antz *cough*), ant societies are female dominated – females are responsible for laying eggs, rearing the larvae, foraging and collecting food, building the nest and defending it against attackers. Males are responsible for … sex, and that’s it. Antony doesn’t deserve the credit; the lead should have been Anthea.

However, this point of the movie didn’t necessarily have to be wrong. Carpenter ants, like most species, only have wings during their nuptial flight, when they mate. During this time, colonies produce winged males and females, who fly out to find a mate and start a new nest of their own. After mating, the males die and the females cut off their wings to begin their life underground. So, flying representatives of the carpenter ant could be male OR female.

But, morphologically the Antony in the film appears to be a queen – a female reproductive ant – not a male. Queen carpenter ants are only produced during the summer months, which might make winter combat rather more challenging for the film’s ant-army.

A bit cold for a parachute…

AntMan_002Moving away from issues of gender, the film also misses a key part of insect biology – all insects are cold blooded, or endothermic. When falling out of a plane at 36,000ft, carpenter ants would be killed by the thin, -60 °C atmosphere. Since they rely on heat energy from the environment to survive, rather than producing their own body heat, ants have a very poor tolerance for low temperatures. Much like reptiles, when ants get cold they slow down, and eventually go into a sleep-like state.

Assuming the plane flew in lower, say 15,000ft, the air temperature outside would still be -15 °C, and the ants would be knocked unconscious, although not killed. Laboratory experiments have shown that C. pennsylvannicus becomes completely inactive below 5 °C, meaning the plane would have to fly in at less than 5,000 feet for the ant helicopters to have any chance of being awake for the descent.

The craziest part of Ant Man

Things only get worse for the crazy ant. The amazing “skill” of the crazy ant, they claim in the film, is that they can conduct electricity. This becomes a crucial plot point when Ant Man uses them to fry Cross Technologies’ computer system. But it is simply not true that any species of ant, crazy or not, can conduct electricity.

The rumours of electrical ants originated from the observation that some ants, particularly invasive ones, can often be seen clustering around electrical wires and plug sockets. However, Prof Adam Hart explained quite clearly last year that ants just like the warm, sheltered crevices of our electrical circuits. They do not conduct electricity, and were they to get into the wire itself they would cause a short-circuit.

One final point on the accuracy of Ant Man’s ants. It is hard to see clearly, but I believe the CGI ants they created lacked a petiole, a small ‘nub’ between the thorax and abdomen, which is very clearly present on the carpenter ant. The petiole is an important part of the insect’s anatomy, providing a flexible joint, enabling them to curl their abdomens beneath their thoraxes and sting or spray prey and enemies.

AntMan_004A mind-controlled ant army?

There’s one final bit of “science” from Ant Man that I’ve not yet mentioned. The mind-control. Throughout the film, Dr Hank Pym displays impressive feats of behavioural control over his ant armies; explained in the film as “electromagnetic stimulation of the olfactory nerves”. So does that have any scientific validity? Well, the field of BCI (brian-computer interface), whereby electrical impulses in the brain are used to communicate directly with a computer (and sometimes vice-versa) is advancing rapidly at the moment.

Animal mind control, of sorts, is already possible. With current technology scientists are able to send fairly simple messages, usually relating to movement, from one person’s brain to a computer, and then into the brain of an animal such as a monkey. Using this technology they’ve been able to make a monkey move a joystick, but nothing more complex than that.

Ants might be easily manipulated in some ways. Dr Pym claims to stimulate the olfactory nerves, tapping into the ants’ sense of smell – this is key because ants communicate with each other largely through smell, and odours can induce strong behavioural responses in ants. Take foraging pheromones, for example – these odours are laid in trails to guide ants to sources of food, and synthesised foraging pheromones have been successfully used to make ants ‘dance’. It is only a few more imaginative steps to move from a synthesised pheromone to stimulating the neurones that normally detect the pheromone. Link that up to a BCI device, and you’ve got yourself a remote-controlled ant army. With

This fantasy is still a very, very long way off, however. Although theoretically possible, our understanding of the human (and ant) brain is still in its infancy, and the potential to send complicated signals and produce any kind of complex behaviour (like, say, spinning a 1 cent coin) would be unimaginable at present.

Although I came away pleasantly surprised by the accuracy of Ant Man, that’s because I had very low expectations. The science wasn’t great, although a lot of it was at least plausible enough for me to say “hmmm”. Exploring the science of the film turned out to be almost as entertaining as watching it.

One of the caveats is that ants tend to only be receptive to particular pheromones in the appropriate circumstances – for instance, ants will only follow foraging trails when it is the right time of the day to be foraging. Clever little ants. So your ant army might just pack up at the end of the working day, whether you liked it or not.

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