Humans develop at a slower rate than other mammalian species, like mice, but scientists are still trying to understand the molecular basis of these differences. Now, researchers from the Ebisuya Group at EMBL Barcelona and PoL-TU Dresden and from the Savitski Team at EMBL Heidelberg show that across 4,000 proteins shared between humans and mice, there is a clear tendency for protein degradation in humans to be slower than in mice.