The biomass distribution of the animal kingdom

Is there really that many arthropods?!?

[this post refers to a 2021 reddit post]

the question

When we think about animals we always refer to the bald eagle or the bengal tiger, but, are they really representative of the animal kingdom? Shouldn’t we start thinking more in an ant maybe? Yes they are small, and mostly helpless, but how many are there? or rather, how much do they collectively weight?

the data

With this question I found a 2018 paper in PNAS from the Weizmann Institute 🇮🇱 and Caltech 🇺🇸 where they obtained and integrated data from multiple previous estimates of the biomass of each taxa in a comprehensive and systematic way.

The “unsurprising” result was that on earth, biomass is centered around plants and bacteria (200:1 and 40:1 compared to animals). I was more interested though in how animals were distributed and which was the proportion of “human biomass“ in our planet. These data resides in figure 1B and that’s what I decided to recreate with exemplary pictures of each group of animals.

💡 In ecology, biomass refers to the mass of living biological organisms (in this plot, animals)

the plot

📝 I guess is important to note that the specific species chosen in each case is not representative of the taxa that groups it, I chose one which had a decent looking image and that was easy to identify for the audience.

I kinda expected bugs to be the first class of animals in biomass but it really surprised me how prevalent they are. Visually, if you put in a weight all humans and bugs on earth the bugs will still be 20 times heavier!!

However, although humans might seem like they have a small percentage here, considering the fact that Homo sapiens is a single species compared to the other groups that encompass thousands or millions of species the value is really high and exemplifies how our population has colonized this planed both in extension and volume (or should I say mass?).

---

other relevant links:

• Check the original post at → r/dataisbeautiful 🔥 where I got almost 50k internet points!

• Check other super cool visualizations of the same data in visual capitalist and vox.com! 👏🏻

Best,

DMP

p.s.

🐊 The reptilian conspiracy: If you’re worried why there seems to be no reptiles (or reptiles with mass) in earth, relax. The authors of the original study did include them in their analysis. Similarly to the amphibians, the numbers were so low and the uncertainty so high that they decided to excluded from the main text and from the figure. When I originally shared the post this particular issue was repeatedly asked so that’s why I decided to include a disclaimer here.