The gut census
Who lives here
Microbial vs human cells
≈ 38T : 30T
roughly 1 : 1 — you’re about half microbe by cell count
A fungal cell vs a bacterium
≈ 100×
larger by volume — why weight and count diverge so sharply
By weight (biomass)
Fungi
~45–50%
Bacteria
~40–48%
Protozoa
variable
Archaea
~1–2%
Viruses
~0%
Estimated and cell-size-corrected — not directly measured. Fungi and bacteria come out as the two heavyweights, fungi possibly the larger. The familiar "0.1%" figures are cell counts, not weight.
By number (particles)
Bacteria
≈ half of all cells
Viruses
≈ bacteria, by count
Archaea
<1%, variable
Protozoa
variable / few
Fungi
~0.1%
Viruses — almost all bacteria-eating phages — roughly rival bacteria, while fungi (few but huge cells) nearly vanish. Bar lengths are illustrative orders of magnitude, not exact ratios.
Size on these charts is not importance. Fungi and viruses are tiny by one measure or the other — yet both powerfully shape immunity and disease.