Military Military ramps up use of underwater drones. What do they do? (+video)

Underwater drones have scientific and civilian uses, like the search for the missing Malaysia Airline Flight 370. Militaries, too, see them as an increasingly useful tool.

By , Contributor

Mass Communication Specialist 1st Class Peter D. Blair/US Navy/Reuters/File

They can range from a svelte 100 pounds to several thousand. They can be snub-nosed, bullet shaped brutes that can dive six miles deep or buoyancy-propelled machines that can gracefully glide for several months at a time. And they can perform a myriad of tasks ranging from tracking pollution to mapping terrain for oil and gas exploration.