This increase in size within a group animals through time, i.e. larger species and larger species are constantly showing up on the evolutionary state, is a well known rule of biology.  We refer to this pattern as Cope’s Rule, named after an American paleontologist Edward Drinker Cope.  At broad levels, Cope’s Rule is definitely true.  The start of life on this planet was microscopic and now we have whales and redwoods. However, a mixed bag of patterns of increasing, decreasing, and no change is body size is seen in organism as diverse as molluscs and mammals.  Even within a single group like mammals, some groups like rodents show little change with time, while whales get larger with time, and horses get both bigger and smaller.

Godzilla appears to be following Cope’s Rule.  So how big will Godzilla be in 2050?  Rhett Allain at Dot Physics calculates this to be 170 meters.  But I, as nerds debating meaningless things will, disagree.  Allain appears to use multiple dates for each iteration of Godzilla.  For example, the 50 meter Godzilla occurs in movies from 1954-1975 and again in 2001.  In Allain’s plots, 50 meter Godzilla occurs in 1954, 1960, 1970, and 1991.  This artificially weights the analysis and treats separate iterations, i.e. species, of Godzilla the same as a single individual of the same species of Godzilla.  To restate, different sightings, e.g. different movies, of the same individual of Godzilla are put into the analysis multiple times even though they are presumably the same individual. I prefer to use a standard paleontological method, specifically the size at first occurrence.

So redoing the analysis, I first find no actual statistical increase in size with time.  That is because the second smallest Godzilla, 55 meters, did not appear until 1999 (purple dot in the graph), the regression between size and time is not significant with this point included.  I am also not sure why the artist of the plot decided to place the 55 meter purple Godzilla out of temporal order. If purple Godzilla is thrown out of the analysis we get the equation

Log 10 Height = -13.94 + 0.008 Year

So in 2050, I calculate that Godzilla would be 288.4 meters not 170 meters.

So why is Godzilla obtaining ever larger sizes with time?  Skyscrapers.  Skyscraper height has increased dramatically over the last century.  For Godzilla to continue to plow through buildings in major metropolises, a more formidable size is needed.  Of course this size change can only be evolutionarily adaptive if it changes the fitness of Godzilla, i.e. in the simplest case the number of offspring passed to the next generation.  If Godzilla is able to topple buildings this might allow for greater acquisition of resources in this case food in the form of people. This would increase the lifespan of Godzilla allow for more reproduction or allow for greater amount of energy to be passed to the offspring increasing their rate of survival  Or perhaps toppling buildings is a sexual display that sexual partners cue on.  Sexual selection!

Of course the real problem of a 55,000 ton Godzilla is the urine production. Using the handy Kaiju post, we can quickly calculate that, 151,436,928 12,921,400 gallons per day.  That is about 1.8 about quarter of the hold of the largest production oil tankers.

The post The Ever Increasing Size of Godzilla: Implications for Sexual Selection and Urine Production first appeared on Deep Sea News.

 The short answer is not as many as you think.

I spent Saturday watching Pacific Rim.  The movie has everything I want in a flick—big-ass sea monsters, big-ass robots, and big-ass robots fighting big-ass sea monsters.  Pacific Rim is undoubtedly the no-holds-bar-over-the-top-action-flick-who-gives-damn-about-plot-or-character-development-o-yeah-it-has-Ron-Motherf’n-Perlman kind of movie we all need.  My wife disagrees but I still love her.

The stars of Pacific Rim are the Kaiju (怪獣) a Japanese word that literally translates to “strange creature”.  Kaiju films are a staple of Japanese cinematography with Kaijuu, like Godzilla, Mothra, or Rodan, attacking each other or better yet a whole city.

Being the complete nerd I am, I waited patiently until I heard the magical words I needed to hear during the move. “That Kaiju weighed 2500 tons.” At 2500 tons and a puny category 3, this monster didn’t even top the scales as the largest.

Kaiju are creatures of a highly toxic nature and have been categorized on the “Serizawa Scale”. Each Kaiju is classified under five different categories. Categories 1 through 2 represent the weakest of the Kaiju, while Categories 3 through 5 are the strongest. The Serizawa Scale measures water displacement, toxicity and ambient radiation levels given off by their bodies when they pass through the breach.

Knowing a Kaiju’s weight I can tell you a lot about Kaiju biology, like how many humans they need to eat per day to survive.

First we need to calculate what is the field energy expenditure, i.e. the number of joules per day to survive, for a Kaiju.  During the film the “scientist” states the Kaiju are related to the dinosaurs.  A previous paper suggests the equation for dinosaurs should be based on those for Komodo Dragons, i.e. active carnivorous lizards.  So

2500 tons = 2,267,961,850 grams

The equation is

FFE=1.07(mass)^0.735

FFE=8.05*10^6 kJ/day

Given the 2500 ton size of the Kaiju, you might be surprised this doesn’t come close the energy demand, 10.14*10^6 kJ/day, for a blue whale at a mere 160 tons.  The Kaiju estimate is just a single order of magnitude higher than that of elephants and rhinos, 5.36*10^5 and 7.10*10^6 kJ/day.

So what’s going on? The FFE is higher for carnivores than herbivore. More energy is required to chase and subdue prey.  That constant search for prey may also require muscle structure for endurance [pdf], increasing muscle mitochondria density, and requiring more energy.  But we accounted for that by using the total bad us flesh munching, bone crushing Komodo Dragon equation.

The real reason? Lizards don’t run as hot as mammals, i.e. they don’t regulate their internal temperature. Komodo Dragons, an active carnivorous lizard, actually do heat up bit, but still don’t suck energy like a mammal.  Keeping the body warm is energetically expensive to maintain, as exampled by heating bills in Boston to keep my Southern butt warm.

So real question is how many humans would a Kaiju need to eat daily to survive?  The human body contains, depending on athleticism, anywhere from 600,000 to 750,000 kilojoules of energy.  Per day the Kaiju would need to eat anywhere between 10.7 to 13.4 humans.  This would mean that it would take a Kaiju, at the quick side, 1,472 years to to eat through the population of Hong Kong, home of the Shatterdome base.

If we assume a Category 5 Kaiju weighs 5,000 tons, then it would only need 17.9 humans per day, taking it 1,102 years to eat its way through Hong Kong.  Perhaps we shouldn’t be so worried about them.

The post How may people does a Kaiju need to eat every day? first appeared on Deep Sea News.