A rock hammer is essential field gear for geologists—not just for breaking rocks, but for any number of other tasks, from hammering pegs into the ground to opening beer cans when the tabs break off . . . to self-defense against rabid bobcats. On 19 April, reported the Tucson Citizen, University of Arizona geologist Rich Thompson and his wife, marine biologist Katrina Mangin, fought with the rabies-deranged bobcat for ten minutes before he dispatched it with his trusty hammer. Thompson informs me that it's the standard Estwing geologist's or prospector's hammer "with a square end and a pointy end," and that's a great testimonial.