Crocodiles live in many different countries and habitats. This generally dictates what food is available and what and how they hunt. I have selected Crocodilus Porosus for the main answer as it my most favourite living dinosaur.
THE JUVENILES
The Saltwater Crocodile of Australasia starts life in a creche, protected by its' mother for the first few weeks of its life. This is typical of many species.
They are largely reliant on insects, but can catch small fish and other small reptiles when they are young. They slowly include larger prey such as rodents, other amphibians, reptiles and larger fish.
THE WANDERER
They can venture well over 300Km out to sea and inland, making them very adaptable to many aquatic and marine environments.
HOW BIG?
When reaching larger sizes and weighing over a ton, or even two ton or more, their diet may include large cattle and other very large animals. They also will feed on carrion and birds when the opportunity exists. The largest ever recorded reportedly measured 28 feet 4 inches (over 8.6 metres). They continue to grow throughout their entire life.
SMART THINKER
They are seen as an intelligent and patient hunter by the way they can identify different animals habits of using a particular entry point or drinking spot, often only once or twice, then remember the time and frequency of this. They will often lay in waiting with only their nostrils and eyes visible above water, for the prey to return, sometimes days later.
THE HUNTER
They will slowly curl their tail, creep very slowly closer, position their legs forward, and then propel their entire body out of the water with such speed and force that often when they miss with their deadly jaws, the force and power of their body is sufficient to knock the prey off-ballance where the crocodile then can have a good chance of snapping its' head sideways and getting a viscous tooth-hold on the prey.
There are many other crocodiles that feed solely on insects, small reptiles and fish, and some may include other invertebrates and carrion in their diet.
A CRANKY BEAST
The Male Saltwater Crocodile prefers its' own large territory and often gets into a deadly fight with others to protect it. Females are sometimes driven off too. Most fights between males occur during the mating season when many males leave their territory in search of a mate.
WATCH OUT
This is also the main time that they become a threat to us as they often venture into cities and townships marine and aquatic areas and won't differentiate between a human and other potential prey if the opportunity presents itself.
Crocodiles are primarily ambush predators. They wait just beneath the water surface, with just their eyes and nose showing. When the prey comes close enough they grab it with their jaws.
Crocodiles lay just beneath the water and try to ambush their prey in a sudden rush. Once griped, the prey is pulled into the water, and the crocodile takes it under the water to drown. The crocodile then takes a grip and spins its body until a lump of flesh is pulled off. The lump of flesh is swallowed whole, as the crocodile doesn't have molars with which to chew its food.
they hide under the water to sneak up to its pray and then quickly grab it with its teeth.
in the science book it says that they both hunt during th night time.
They are ambush killers, lying in wait, then rushing forward to grab their prey, then taking into the water to drown and dismember it.
They ambush their prey
They stalk their prey noiselessly and attack them at the right opportunity.
So they can keep the element of surprise to attack their prey.
Tiger. Tigers are known to prey upon "gators" and crocodiles. "Gators" and crocodiles seldom attack tigers.
Crocodiles attack most of the time from the water: they spot their prey, go deep, and then launch an unsurprising attack at their confused meal ;) However, crocodiles can run very fast on land (some crocodiles can run the same speed as a horse for short distances), and so they can take mammals that way too.
Sumatran tigers are prey to saltwater crocodiles and large reticulated pythons. Bengal tigers are prey to saltwater crocodiles, mugger crocodiles, and large packs of dholes.
They dont really have enemies...they just have prey( their food). They will fight to take prey from other crocodiles, or to keep what they have.
Their diet to small rodents makes it suitable for their living conditions unlike regular crocodiles. They have developed huge teeth that help them fish and grasp hard on any prey they decide to attack.
People.
Crocodiles are both predators and prey. They prey upon just about anything including animals, fish, and birds. Some of the animals which prey upon them are large cats, feral pigs, and other crocodiles.
Crocodiles first drown their prey and the rip off chunks and pieces of the prey then swallow the pieces because they cant chew.
Young Nile crocodiles are prey to african rock pythons. Adults have no predators. Young saltwater crocodiles are prey to reticulated and Burmese pythons. Adults have no predators. Young mugger crocodiles are prey to reticulated and Burmese pythons. Bengal tigers occasionally prey on adults.
Crocodiles shut their mouth really quickly so that their prey like the fishes can't escape. If their prey keeps on escaping, the crocodiles will become very hungry.