Why there probably isn’t a ghost ship full of cannibal rats headed for the British Isles

January 25, 2014 • 10:24 am

by Greg Mayer

There’s been a lot of media attention the last few days about the prospect of a derelict Russian passenger ship, the Lyubov Orlova, crossing the Atlantic from Canada (where it was last berthed) and crashing into Ireland or Britain, spilling disease-ridden, inbred, cannibal rats on their shores. The ship was being towed to the Dominican Republic when it broke away and floated off last year. The Sun has had perhaps the most dire take on the story, headlining their piece “Ship of Ghouls“.

A scary picture from the Sun.

That the ship, laden with cannibal rats, might fetch up on shore, however, seems very unlikely. As the Guardian reports, both the Irish and British coastguards downplay the possibility. In particular, Irish officials note that they have looked for it, can’t find it, and suspect that it may have sunk.

But there’s another reason that it is highly unlikely, having nothing to do with whether or not the ship is still afloat, and because it reveals an important biological principle, it’s worth a mention here at WEIT: an ecosystem without primary producers cannot be sustained except for very brief periods of time. Unless those rats have been raising crops on the ship, the last one, cannibal or not, died some time ago.

There are very few “laws” in biology in the strong sense with which the term “law” is used in physics. Mendel’s “laws” of heredity, for example, have numerous exceptions and limiting conditions. When I teach genetics, I refer to them not as “laws”, but as Mendel’s “useful generalizations”. But one of the biological principles that does have law-like status is that primary producers must be at the base of every food web, and that energy is lost at every step in the food chain. Perhaps the reason these principles are law-like is because they derive so directly from the laws of thermodynamics: energy must be put in to a system to avoid entropy increase (so we must have producers to capture energy) and no energy transfer is 100% efficient (so there’s less energy available further up the food chain than at the bottom).

These ecological principles are often expressed in terms of a “trophic pyramid“, a visual representation of the fact that primary producers (usually green plants that capture energy by photosynthesis, but also photosynthetic and chemosynthetic bacteria) outnumber herbivores (primary consumers), who outnumber carnivores (secondary consumers), who outnumber top carnivores (tertiary consumers; there are rarely more than four or five levels in a food chain).

Trophic pyramid.
Trophic pyramid.

The exact shape of the pyramids depends on the efficiency of energy transfer between levels, and whether the pyramid is based on number of individuals, biomass, or energy flow units. As a rough guideline, efficiency of transfer between levels is often estimated at about 10%; the efficiency of capture of solar radiation is much lower. These important details can be investigated here and here, for example, but they do not alter the fundamental principles.

Viewing ecosystems in this manner owes much to an extremely influential paper, “The trophic-dynamic aspect of ecology“, by the young limnologist Raymond Lindeman, who tragically died of an obscure form of hepatitis a few months before the paper was published. The very interesting story of how the paper was almost not published, first being rejected by Ecology for being too theoretical, but finally accepted, has been told by Bob Cook.

Raymond Lindeman (1915-1942). He could have told you why there are no cannibal rats threatening Ireland and the UK.
Raymond Lindeman (1915-1942). He could have told you why there are no cannibal rats threatening Ireland and the UK.

So, what does this all mean for the people of Ireland and Britain? You can relax. Although rodents will resort to cannibalism when food supplies run low (though I’ve never seen it in rats myself, which, by the way, are much friendlier and make better pets than mice), an ecosystem based on cannibalism cannot persist, because there is no energy input to the system, and there cannot be a 100% efficient transfer, so the rat-level in the “food chain” will continually decrease in number and biomass. How long a bunch of rats resorting to cannibalism would last depend on details such as the number of rats, their caloric needs, etc., but suffice it to say that no reasonable numbers for those details could get the rats to last nearly a year. The caloric needs of mammals are quite high, and they need to eat a lot. (This may not be a comforting thought, but a ship full of anacondas and reticulated pythons could last a year or more at sea, without even having to eat one another, because of their low caloric needs. They would come ashore hungry, though.) The reason I say “probably”, rather than “definitely”, is because it is conceivable that large stores of food were left behind, and depending on the quantity, these could support a rat population for some time (recall that in most zombie movies the survivors rely on canned goods for survival, although in the last season of the Walking Dead they did begin farming). But since the ship was being towed for salvage, I doubt the kitchens and larders were full.


Cook, R.E. 1977. Raymond Lindeman and the trophic-dynamic concept in ecology. Science 198:22-26. pdf

Lindeman, R.L. 1942. The trophic-dynamic aspect of ecology. Ecology 23:399-418. pdf

Sterner, R.W. 2012. Raymond Laurel Lindeman and the trophic dynamic viewpoint. Limnology and Oceanography Bulletin 21:38-50. pdf

77 thoughts on “Why there probably isn’t a ghost ship full of cannibal rats headed for the British Isles

      1. The Chinese use cat and dog fur in their cheap clothing manufacturing, and they don’t care much how it is made available to them. Most of it is supplied by gangs (or groups, if you prefer) of roaming animal catchers who do not have much concern for how the animals are treated. Although most, if not all are captured on the streets, strays are not the only, or even main source, since their fur is often less than desirable. The animals are caught and packed in until the cages are full (all the way full, as in nothing else can be crammed inside), unloaded in manners that often damage/break bones, hung up and skinned while alive and the dying animals are sold for meat. Collars or other id is destroyed. It is a horrific practice and I attempted to protest by not buying anything made in China, but on a normal income it has proven to be pretty much impossible. But I won’t buy anything with fur on it. Apparently Chinese manufacturers don’t care about their pets any more than their employees.

  1. “energy must be put in to a system to avoid entropy increase.”
    This is not really correct: entropy will increase anyway, but the input of energy will provide an increase in free energy, which can then be used by living organisms.

    1. There was an interesting description (for those of us who has never studied non-equlibrium thermodynamics, NET) of “life as thermodynamics” by Russell et al. [“Turnstiles and bifurcators: The disequilibrium converting engines that put metabolism on the road”, Biochim. et Biophys. Acta, 2013] They think “Atwood engines” of “free energy conversion” is the bottleneck constraint that characterizes life, solved by such minimal engines as key electron bifurcating metal atoms (inherited in some of today’s enzymes).

      To get there they argue, convincingly to me (but see above), that NET is qualitatively different but can be mapped to ET. Specifically, the meaning of free energy in NET is that it is a measure of entropy:

      “[deltaG/kT means]… that “free energy” is therefore not physically an “energy” (of any stripe), but is just a dimensionless numerical quantity measuring how far from equilibrium the system currently is.”

      It is their contention that the mapping of NET onto ET works but obscures “how the dissipation of one diequilibrium state has physically led to the creation of another.” Specifically I think, to keep the entropy increase confined to the irreversible process of a bounded system the entropy flows (of metabolism, say) are orthogonal (but can be coupled). I didn’t know that, nor that the material export to the universe didn’t increase entropy.

      Anyhoo, it is true that input of energy will provide an increase in free energy, but the innards of that claim is, in site fixture Ben’s words, not to be fondled lightly. =D

      1. Oy.

        “to the irreversible process of a bounded system” – to the irreversible process_es_ of a bounded system.

        “material export” – material exchange.

      2. Worse:

        “the meaning of free energy in NET is that it is a measure of entropy” – the meaning of free energy in NET is that it is a measure of disequilibrium.

        1. This is interesting, and I should look up that paper. I like to fondle ideas that life is a dynamic system in which chemical reactions are perpetually tilted away from chemical equilibrium. 🙂

      3. It seems pretty obvious that, to get from fermions to fondling, you need some sort of physical process that increases material complexity. And some sort of ratcheting mechanism would also seem quite natural — that, once you get to a certain level of complexity, so long as the energy input can be sustained, you’re unlikely to go backwards.

        Whether Russell et al. have the actual such process properly characterized or not, they’re very likely not too terribly far off the mark.


  2. It’s notable that the same people who claim that the second law of thermodynamics disproves evolution are the one most likely to believe woo filled claptrap such as this story about cannibal rats.

    It’s not too dissimilar from children around a campfire late at night telling scary stories to frighten each other.

  3. a ship full of anacondas and reticulated pythons could last a year or more at sea, without even having to eat one another, because of their low caloric needs. They would come ashore hungry, though

    Snakes On A Ship!!!!!

    1. I was going to say that. After planes and trains, what else is left? I can’t see the situation being less than explosive if there is a quick escape. Perhaps Snakes on a Space Station? Probably been done.

  4. I agree that this ship has most likely sunk, what with the violent storms that occurred in the northern part of the Atlantic Ocean over the past year.

    Tabloids sell well with such dramatic headlines, and most of the time the contents are completely false.

  5. Since we’re on the subject of zombies…as much as I enjoy watching zombie movies (and I honestly do!), the movie portrayal is virtually always a gross violation of conservation of energy.

    When the hero blasts huge holes in the zombie’s torso with a shotgun and it keeps shambling on? Well, the reason people go down in those situations is because the physical trauma is such that the body no longer has enough physical reserves to keep going. It’s like your car still running for more than a few seconds after you’ve severed the fuel line.

    And the zombie virus that reanimates putrid corpses? That directly plays to the trophic levels of Greg’s post here. The energy necessary to repair the massive tissue and other damage just isn’t present in a picoliter of virus DNA — especially not when the virus needs the host’s energy to replicate in the first place.

    It does, though, make for some seriously creepy movie scenes….


    1. Right here is where the rumor can start that there are zombie cannibal rats on the ship. Picked up by the media without fact-checking, the rumor can expand into an unverified story from anonymous sources that the rats had chewed into the storage area and got oozed on by the meteor that was stowed down there! By the time it floats to shore there will be large populations of the credulous believing that mutant, zombie cannibal rats are spilling into Britain. Hoo, hoo, this will be fun!

      1. ‘Mutant zombie cannibal rats’

        Man, if the headline writers ever get a sight of that, we’ll never hear the end of it… 🙂

    2. You are obviously ignorant of the incredible properties that post-humans possess on account of there diet of fresh brains.

            1. With semi-automatics, yes, but not shotguns.

              Plus, one should put some thought into conservation of ammunition. Once the Zombie Apocalypse arrives, the ammo plants are going to shut down, and we’ll soon be back to flintlocks with homemade powder. If you need to double-tap to survive the onslaught of the horde, yes. Otherwise, take your time and be certain of your shot. Deep, calm breaths; smoothly and gently pull the trigger. If sniping, time the release so it’s between heartbeats.


              1. Anyone truly prepared for this scenario (survivalist are always prepared for any type of apocalypse) will have huge piles of ammunition already secured. They will also have the equipment to make their own ammo out of whatever is lying around. Did you learn nothing from “Tremors”?! Humans always have creative ways to handle these situations. Even if their planning and stockpiles are inadequate, they never fail to win out against any odds, even it relies on physically impossible means. You obviously need to increase your diet of Asylum movies. You probably not really need to prepare for a solar eclipse punching a hole in the atmosphere and allowing all the super cold air(?)from space to rush through it and freeze the planet. Or at least Australia. And mostly those teenagers skipping school to go surfing. At least they didn’t have any trouble with those pesky mutant giant crocodiles or great white sharks, I guess.

      1. You guys are missing the point. You’re not supposed to take zombie movies literally. It’s a metaphor.

        1. You jest, but that’s actually one of the great things about zombie movies. So many of the good ones are not-so-thinly veiled metaphors for all kinds of really cutting social commentary.

          Mindless hordes roaming shopping malls, crushing anything in their path in a desperate search for the brains they think they need but aren’t quite sure why, and never satisfied with all the wealth they’e surrounded by that they so casually destroy in their singleminded determination? Tell me that’s not even more terrifying than the graphic displays of guts and gore!


  6. Professor Mayer laying the biological smack down!

    This story has gone through my FB feed numerous times, shared by friends for whom I now have a little less respect. What I want to know is how does a ship with a bunch of rats on it equal a “ghost ship” or “ship of ghouls”? Even if this ship and it’s rats show up, so what?

    Some peoples’ aversion to thinking about things with a level head is really dismaying.

    1. I shared it because I thought it was funny. I didn’t imagine anyone would take it seriously! I mean what difference would a few more rats make anyway?

      1. Oh, people who shared it in the spirit of “would you look at this baloney” retain full respect reserves.

        It’s just that the comments those friends of mine who shared it made about it were…telling.

        1. My theory of suburban life is that two main motivations struggle for supremacy, boredom and anxiety. Most people are bored out of their brains and something like this is a godsend, they’re actually hoping it happens (at least a bit) so that the boredom may be relieved for a moment. Since a few more rats won’t make any difference in the world, it doesn’t set off their anxiety much. I note that the internet is still debating this scenario, some claiming there was much food on board and the ship unlikely to have sunk.

    2. Leaving zombies of any kind aside, a ship at sea without a human (and still living) crew are frequently called “ghost ships.” I suppose because it generates more interest than ‘abandoned.’

  7. To me the most interesting thing about this story is that in an era of global satellite surveillance, when AT&T can ping your iPhone and tell you where you left it, it’s apparently still possible to lose track of a cruise ship full of navigation equipment.

    1. AT&T can’t find your phone if it is turned off. And I recon the power was off on the ship when it broke free.

      But it does surprise me that this possibility isn’t considered enough to put a GPS device on the ship while it is being towed.

      1. “AT&T can’t find your phone if it is turned off.”

        That’s what the NSA wants you to believe.

        Seriously, though, the real point is as you say: surely it would have been worth the relatively minor cost of ensuring there was a working tracking device on the ship before cutting it loose in stormy seas.

        (And by the way, you mean “reckon”, not “recon”.)

          1. The way it works is that an Apple server lets the phone know that somebody wants to know where the phone is, and the phone tells the server.

            (I don’t know if it’s a push or pull method; it could either be that the server sends the signal to wherever on the network it thinks the phone is, or it could be that the phone periodically checks with the server to see if the server is interested in its location. Or maybe even a combination of the two.)

            All of that requires a lot of energy — energy to run the wireless network transceivers to receive and send the messages back and forth from the server to the phone, energy to receive and decode GPS signals, all that sort of thing.

            It’s possible for the iPhone to pretend it’s off but still do that sort of thing, and it’s even reasonable to suspect that the three-letter agencies have methods of corrupting it into behaving like that.


            It’d still take energy to do so, which would be quite noticeable. If you pick up a phone that’s supposedly powered down and it’s warm to the touch, that’s a sign of hanky-panky — triply so if the battery is drained from when the phone had allegedly been turned off.

            If that sort of thing became common, people would rapidly lose trust in the devices and the companies selling them, and you’d see the same sort of thing happen to American mobile phone companies that’s starting to happen right now to American telecommunications equipment manufacturers and Internet services companies in the wake of the Snowden revelations. Some jackbooted bureaucrat might see some sort of short-term gain from that sort of hanky-panky, but the long-term damage to the economy (and to the bottom lines of the companies that buy the politicians that appoint the bureaucrats) wouldn’t be worth it.

            Not that that’ll necessarily stop them….



        1. Yes and no.

          If the phone has not been compromised somehow, powering it off is plenty.

          If you’re worried about a three-letter agency tracking you…well, yes, removing the battery will stop them from using your phone, but it won’t stop them from tracking you with the self-contained GPS transmitter they attached to the inside of your wheel well with a magnet. Besides, as soon as you put the battery back in your phone, you could be tracked again, so why own it at all if you can’t use it?

          Also, your phone doesn’t need its own GPS receiver to locate you. Simple radio triangulation of the cellphone towers that can “ping” it is enough. At the very least, it’ll get your location down to the block, and likely to the house. GPS, on the other hand, will know which room you’re in (if you can get a signal indoors).

          In other words, if you don’t want to be found, your phone is the least of your worries. If you’re going to have and use a phone, there’s no point in worrying that somebody can find you.



          1. I did specify “and don’t have a GPS device in it”.


            Simple radio triangulation of the cellphone towers that can “ping” it is enough

            Surely that triangulation cannot work if you have removed the battery?

            1. Yes, the phone needs a power source for the towers to triangulate it…but most phones being sold these days don’t have removable batteries. Besides, you can’t use the phone if you’ve taken the battery out, and the moment you put the battery back in to use it the phone company knows your location.

              Unless you’re going to go super-paranoid and pay cash in a surveilance-free area for a phone you’ll only power on a single time, the only sane options are to either not carry a phone at all or not worry about the fact that your phone’s location is easy to determine.

              (I suppose, if you’re planning on visiting somewhere you’d rather “they” not be aware of, you could just turn off your phone for the duration of the trip, but that kind of behavior is conspicuous in and of itself. Probably much smarter to leave the phone turned on but leave it at home.)


  8. “suffice it to say that no reasonable numbers for those details could get the rats to last nearly a year.”

    Apparently, after being seized by creditors, the ship was tied up in Canada for a couple of years before the attempted towing. We may be looking at 3 years with no food added to the system, so the probability that there are still rats aboard appears to approach zero.

              1. Well…they are cannibal zombie rats. I imagine they’re probably also all drunk because they’ve turned all the water into wine….


  9. I wonder how many factory workers it needs to keep investment bankers on their vertiginous rung of the food chain?

  10. “This may not be a comforting thought, but a ship full of anacondas and reticulated pythons could last a year or more at sea, without even having to eat one another, because of their low caloric needs. They would come ashore hungry, though.”

    I think I smell The Asylum’s next cheap horror film.

    “Snakes on a Boat”, tagline: “They’re on shore leave – to kill!”

    Although “Rat Boat Ghost Ship” would have been catnip to them too.

  11. They’ll make a movie about this one day, whatever the outcome.

    Except the ship will be drifting towards the USA (because if any other country were threatened -who gives a f**k there’s no story) The rats would be replaced by nerve toxins and the ship would have originated in a ficticious West African republic.

    The only person who believes in the threat will be the local marine biologist who runs the aquarium on the boadwalk and no one will listen to him; he gets fired by the mayor (who’s daughter he is dating) and then goes out to sea to scuttle the incoming ship. The fast drifting vessel suddenly appears out of the mist and slices through our hero’s boat sinking it. After swimming back to shore he realises that he is “going to need a bigger boat”

    He enlists the help of Roosovelt Mendle a local alcoholic skipper who just happens to own the only fast metal hulled vessel in town. He also has a partially functioning cruise misile which he purloined from the Iraq war and which our hero will have to reprograme with the aid of a special app on his iPhone to target the incoming ship instead of the Central Library in Bahgdad.

    Venturing out into the summer mist again in search of the Ship of Death, our hero watches as his skipper drinks himself into a useless stupor ……….

    Ok, that’s enough of that – I think I would prefere the rats.

    1. Except the heroic mad scientist can’t get to the boat because the bridge has been shut down by the governor because the mayor didn’t endorse him in his reelection bid…

      …nah, you’re right. That’d be going too far for believability even for The Asylum.


        1. Boat, schmoat. This is Jersey — we’re gonna need more cement for those shoes!

          …at least, if it weren’t amateur hour in the governor’s corruption department, we would….


  12. This is the first I’d heard of cannibal rats, but I have heard a theory that all economies will eventually become service-based economies as they “develop.” This seems to me like an economic version of cannibalism. If all we do is provide services for each other, where do we get our food and our durable goods, etc.? There has to be a baseline minimum of agriculture and industry to support all those service types.

    1. It’s worse than that, actually.

      Virtually all economists assume that perpetual growth is an essential part of any healthy economy.

      The logical conclusion from that observation is that schools of economics do not properly educate future economists on basic mathematical principles, especially including the exponential function.



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