In the course of the Vietnam War, the Viet Cong created extensive underground complexes. Whenever troops would uncover a tunnel, tunnel rats were sent in to kill any hiding enemy soldiers and to plant explosives to destroy the tunnels. A tunnel rat was equipped with only a standard issue .45 caliber pistol and a flashlight, although most tunnel rats were allowed to choose another pistol with which to arm themselves. The tunnels were very dangerous, with numerous booby traps and enemies lying in wait. Often there were flooded U-bends in the tunnels to trap gas. Guards manned holes on the sides of tunnels through which spears could be thrust, impaling a crawling intruder. Not only were there human enemies, but also dangerous creatures, such as snakes, spiders, scorpions, and ants. Black-Bearded Tomb Bat (Taphozous melanopogon) and Lesser Dawn Bats (Eonycteris spelaea) roosted in the tunnels and were a harmless nuisance if awoken.