Lionesses are powerful animals who usually hunt in groups and stalk their chosen prey. They can reach speeds of 59 km/h (40 mph), although, only for short bursts, so they have to be close to their prey before starting the attack. They take advantage of factors that reduce visibility; many kills take place near some form of cover or at night. They sneak up to the victim until they reach a distance of approximately 30 m (98 feet) or less. Typically, several female lions work together and encircle the herd from different points. Once they have closed with a herd, they usually target the closest prey. The attack is short and powerful, they attempt to catch the victim with a fast rush and final leap. The prey usually is killed by strangulation.