Petsuchites

Excerpts from a journal left at a ruined campsite. Most of the book is ripped, but there are a few entries that are still legible.
8 Days After Leaving It's tracking us. We were sure we had gotten away from it, but Micheal swears he saw a flash of white in the river we've been following. I didn't believe him at first, but then I heard it. The low growl that I swear turned into a chuckle near the end. It's taunting us. I don't know when, but it must be getting ready to attack us. Micheal says we should split up, but I doubt that will make any kind of difference. If it's gone this long without attacking us, it could pick one of us off and then just continue stalking the other without them knowing. And then they'd be alone. I can't do that. 
13 Days After Leaving I can see its horns silhouetted against the moonlight. This is the first time it has completely revealed itself to us and I'm afraid this is it. Our last night. The petsuchite is done hunting us and there's nothing we can do to fight back. We have weapons, but we can't hope to do anything with them. It is over three times the size of us and twice as clever. If you read this, send my love to my family. And don't tell them about the mess my death left behind.

Basic Information

Anatomy

The petsuchite resembles a massive albino crocodile with thick curved horns similar to those of an antelope. Its scales and horns lack pigment, and, as such, are generally an ivory white. Some petsuchites which have lived outside of the desert for multiple generations develop brown and light blue scales which help them to camouflage in coastal waters and riverbeds. Otherwise, the only colour on its body comes from its eyes, which range from pink to a deep red. Petsuchites are typically between 15 and 20 ft long and can weigh as much as 2,800 lbs. Like a crocodile, both its upper and lower jaws are the same size. This means, that as it closes its mouth and interlocks its teeth, it appears as if it is grinning. This, along with its ability to stalk its prey over weeks without eating, drinking, or sleeping, lends to its image as an exceptionally clever predator. Its movement is surprisingly quick for how heavy it is, and its sharp claws permit for a level of climbing when necessary. It can run around 40 ft or climb roughly 15 ft in 6 seconds. Despite the enormous power in its legs, however, it primarily attacks its prey using its teeth, tail, and horns.  The teeth of the petsuchite can cut through stone with ease, and grind flesh and bone quickly so that it might continue its hunt. The tail carries a powerful swing as well, but its true power comes from its horns. Somehow, it is able to concentrate energy from the sun and direct it as a beam towards its enemies.

Genetics and Reproduction

It is unknown how, when, or even if petsuchites reproduce. Some claim that they were originally created in large numbers, but the gods feared them so much that they took the ability to procreate away from them so that they would not take over the world. Some have claimed to have seen infant petsuchites, but these sightings have never been confirmed and the few autopsies ever performed on deceased specimens were unable to break through flesh without damaging organs which could prove anything conclusively.

Additional Information

Perception and Sensory Capabilities

Petsuchites have incredible eyesight, both in daylight and at night. They tend to hunt more frequently at night to take advantage of other creatures' relatively poor night vision. Their sense of smell also aids them in their hunt, both on land and in the water. Covered head to toe in heavy scales, its senses of hearing and touch are limited. That being said, its horns are incredibly sensitive and can sense strong vibrations in the air from around 40 ft away.