Science, Discovery, Tech and Environment · 3 March 2026
MIT scientists identify 541-million-year-old sea sponges as Earth’s first animals
Exam-focused facts from the 3 March 2026 current affairs briefing.
Key facts
- MIT researchers detected chemical fossils (steranes) in rocks over 541 million years old, confirming soft-bodied sea sponges as the earliest animals.
- The study, published in Proceedings of the National Academy of Sciences (PNAS), analysed Precambrian samples for 30-carbon steranes unique to demosponges.
- Lab burial simulations of modern sponge sterols matched the ancient rock traces, providing three converging lines of evidence: rock samples, living sponges, and lab results.
- Demosponges synthesise these sterols via enzymes absent in bacteria, pushing animal origins deeper into the Precambrian and predating the Cambrian explosion.