Mole rat continuously grows new teeth in shark-like conveyor

A shark continually grows new teeth. Those at the front of its mouth fall away, only to be replaced by fresh rows that move forward like conveyor belts. By contrast, we humans only have two sets of teeth. The first falls away during childhood leaving a second set to last us for the rest of our lives. Most mammals are like us, but there are some notable exceptions. The silvery mole rat of Kenya and Tanzania continually replaces its molars in an unsettlingly shark-like way. New ones sprout from the back of its jaw and slowly make their way forwards. The front ones, having been ground away, are absorbed. Back in 1957, Stuart Landry first noted that the mole rat has more molars than other rodents – up to seven, compared to the usual four or five. No one picked up on that piece of information for decades, until Helder ...