I heard about Larger cats eating the cubs. Is it some kind of facultative cannibalism or they can eat there own kind like that?
What are the facultative cannibalism present in animal kingdom?
What is the genetic origin?
Lions are a classical example of cannibalism. To understand why this occurs we have to understand their mating system.
Males have harem of females and males fight in order to access a harem (Note: females may also take part in the battle depending of which male they prefer). When a male takes over a new harem, he kills the youngs of the previous male if these youngs are still dependent on their mother. The reasons are:
In short, a male kills the youngs when he takes over a new harem because these youngs do not carry his genes and prevent this new male to optimally pass on his own genes as the offsprings of the previous male consume time and energy from the females of the harem.
And well… once the offsprings are killed, it would be a shame to waste all this good and fresh meat. Better to eat them!
In the cases of lions, cannibalism does not result from food shortage but from "not wasting food". I think that the "not wasting food" hypothesis is the most explanation for cannibalism (I am not sure though). I guess that most often the "not-wasting food" occurs after death due to competition as it is the case in lions.
There are many cases of cannibalism in the animal kingdom. Chimpanzees eating other chimpanzees and bears eating other bears. In the tiger salamander, there are cannibal morph and normal morphs. In this species cannibalism is very frequent as in nature one offspring over 5 is eaten through cannibalism (if I am not mistaken). Cannibalism is very common in prairie dogs as well (Reference). In Dragonflies cannibalism represents 95% of the total mortality (Reference).
Sibling sharks eat each others in their mum's womb. Here is a video on the subject. This type of cannibalism is called siblicide.
In many species (including the dragonflies example above) the old individuals eat the youngs. This is referred to size-structured cannibalism.
Fillial cannibalism is a type of cannibalism when the adults eat the own offsprings as it is the case in the prairie dogs example I cited above.
Have a look to the wikipedia links for fillial cannibalism, sexual cannibalism and siblicide, they go further than my answer.