One of the strangest groups of creatures of all is the sea squirts. Their comical title belies the fact that although they are still invertebrates, they actually belong in the same phylum as we do ...

Illustration of a squid-inspired Kraken from Twenty Thousand Leagues Under the Sea by Jules Verne, 1870. Image via Wikimedia Commons Jon says, 'Squid and octopus really are unusual animals. Their body ...