A new study reveals that the sensitivity of teeth, which makes them zing in a dentist's chair or ache after biting into something cold, can be traced back to the exoskeletons of ancient, armored fish.

Moreover, this keratinous covering was far more substantial than previously constructed. The Borealopelta fossil, which preserves the most armor, shows that keratin sheaths increased the linear ...

Heavy Armor The ship's steel armor weighed 23,000 tons—more than 30 percent of Yamato 's total weight. The Imperial Navy developed new ways to harden steel and otherwise improve armor technology ...

Nervy human teeth arose from ancient armored fish scales The sometimes uncomfortable sensations we feel in our teeth may be an evolutionary holdover from the scaly exteriors of ancient armored fish.