Interspecies Conflict/Sleep Attack
I was wondering why predators don't attack prey while sleeping. I think a lion attacking a sleeping cape buffalo would have much better chances of killing it. Wouldn't you agree?
Predators aren't opposed to attacking sleeping prey, but to do so doesn't always work in their favor. We'll use the lion as one example. Lions are nocturnal (active at night) and sleep over half their lives (and rest a large majority of it too). Usually lions are active for a 4-6 hour window at night/early morning, and are not a threat to others for most of the remaining hours (sleep/rest time). Zebra will sometimes pass close to a group of lazing lions because they know they aren't in immediate danger. Lions will attack in the day, but prefer the cover of night. Many animals that would be prey sleep the same time the lions do. Lions have to see what is available during the short time they are active. The Cape buffalo sleeps in groups (with individuals in very close proximity to each other), so to attack one would rouse the whole herd. Lions don't want to deal with a large group of angry half-ton bovids just to grab a meal. When lions (and other predators) attack, they target 2 types of animals: weak ones & solitary ones. Predators will try to pick out the smaller, weaker animals in a group, or will try to separate one from the others and pick it off (to avoid a counter-attack from the remaining members). This provides them with the best chance to make a kill. Some herbivores take turns sleeping or employ a "lookout" to alert the herd if danger approaches. If a Cape buffalo decided to sleep away from the protection of the herd, it could be overcome easily by a group of lions, but the buffalo isn't going to allow itself to be vulnerable if it can help it.
Another example that can be used (to illustrate the other side of the coin) is the predator/prey relationship between the leopard & the gorilla. Leopards will attack sleeping gorillas, and attempt a quick throat-bite/drag away to keep the attacked ape from alerting the others. A large male gorilla would have a good chance of repelling a leopard face-to-face, but an ambush during sleep is hard to defend. One leopard reportedly returned to the same gorilla troop several times to prey on sleeping individuals.
Predators will indeed attack sleeping prey, but only if it's the easiest way. For some predators it is; for some it isn't. If targeting weak or solitary animals is easier, that's what they'll do.