Sorex araneus, the European shrew, is a small, insectivorous mammal known for its high metabolism, venomous saliva, territorial aggression and seasonal skull shrinkage. Its genome is notable for an unusually high rate of chromosomal rearrangements. DOI: 10.1038/s41586-021-03451-0 Author: Jayden Rubio (IES Domènec Perramon)