Planktonic foraminifera are pelagic protists frequently used to study paleoenvironmental change. Many planktonic foraminifera, like other taxa in Rhizaria, reach gigantic proportions relative to other pelagic protists (> 600 μ m), placing them in a size class dominated by metazoans. Here, we combine new and existing respiration rate measurements, micro‐CT scans, and test size measurements to investigate allometric scaling of m...