Steenstrupe was a Danish zoologist, biologist, and professor famous for naming and describing the giant squid 'Architeuthis dux' ('ruling squid') in 1857, previously famous in legend as the kraken. He also discovered the possibility of using the subfossils of the Postglacial period as a means of interpreting climate changes and corresponded with Charles Darwin about barnacles, sending information and specimens. In 1857, he was elected a foreign member of the Royal Swedish Academy of Sciences.