Zebras are preyed on mainly by lions. Leopards, cheetahs, spotted hyenas, brown hyenas and wild dogs pose less of a threat to adults. Nile crocodiles also prey on zebras when they near water. Biting and kicking are a zebra's defense tactics. When threatened by lions, zebras flee, and when caught they are rarely effective in fighting off the big cats. The zebra can reach a speed of compared to for the lion, but maximum acceleration is respectively and . A lion has to surprise a zebra within the first six seconds of breaking cover. However, a 2018 study found that zebras do not escape lions by speed alone but by laterally turning, especially when the predator is close behind. With smaller predators like hyenas and dogs, zebras may act more aggressively, especially in defense of their young.