The saltwater crocodile is the largest living reptile species. It can grow up to six metres and is a serious
threat to humans. Saltwater crocodiles have evolved special characteristics that make them excellent
Large saltwater crocodiles can stay underwater for at least one hour because they can reduce
their heart rate to 2-3 beats per minute. This means that crocodiles can wait underwater until they
see prey, or if people are using the same spot regularly, the crocodile can wait underwater until
someone approaches the water’s edge.
A crocodile can float with only eyes and nostrils exposed, enabling it to approach prey without
When under water, a special transparent eyelid protects the crocodile’s eye. This means that
crocodiles can still see when they are completely submerged.
The tail of a crocodile is solid muscle and a major source of power, making it a strong swimmer
and able to make sudden lunges out of the water to capture prey. These strong muscles also
mean that for shorts bursts of time crocodiles can move faster than humans can on land.
Crocodiles have a thin layer of guanine crystals behind their retina. This intensifies images,
allowing crocodiles to see better at low light levels.
Crocodiles have a ‘minimum exposure’ posture in the water, which means that only their sensory
organs of eyes, cranial platform, ears and nostrils remain out of the water. This means that they
often go unseen by prey, but if they are observed, the prey is often not able to tell how big the
Crocodile eyes are located very closely together and they are oriented forward. This enables them
to judge distance very accurately so they can determine the exact location of their prey prior to
Crocodiles have excellent hearing, which helps them to locate prey particularly in poor light or low
While crocodiles may regularly lose teeth, they have a second tooth sitting in reserve underneath the external tooth, which can replace the lost tooth.