[jbotz]

The 97%-3% numbers came from the top of my head from an article I read some years ago (so slightly outdated) and obviously these kinds of estimates have a significant error bar, but also the ourworldindata page you link to talks about something slightly different; they talk about all mammals, which includes marine mammals but excludes other vertebrates, like birds and reptiles. My numbers were, at the time, cited (as I stated) as "terrestrial vertebrate biomass", which would exclude marine mammals but include birds and reptiles. I think all birds would be considered terrestrial vertebrates because even penguins have to come on land to breed.

[aziaziazi]

Thanks for the clarification! That makes sense.