This arms race in the deep fascinated me 25 years ago when I first heard about it. I was working on natural history reference books when an artist colleague drew my attention to the strange pencil thin lower jaw of the whale beneath its monster head. Didn’t that jaw look a little like a squid tentacle? This was the beginning of my fascination with mimicry and I surmised that the encounter began when a squid mistook the jaw looming into view for another squid. I published a short article on it in the Forum section of New Scientist, now available, like most of their back issues, online. I also made it into Heathcoat Williams’ book Whale Nation.
No evidence for or against has emerged since until this week, when a BBC natural history piece on their website reported that “The world's biggest squid species have developed huge eyes to give early warning of approaching sperm whales”. The eyes can measure up to 11 in across.
There is little light at these depths which is why the squid might see the row glint of teeth (suckers?) on the jaw but not the huge bulbous head of there sperm. Sperm whales have echolocation to spot squid but the squid only have eyes. The squid need acute vision to see the whole sperm and act accordingly.
To confirm this theory, encounters between squid and sperm whales would need to be filmed and I don’t expect my theory to be confirmed any time soon, but it’s good to have a pet theory that stays more or less alive.