Harry's days began to take on a pattern. He would go out with Slytherin in the morning, patrolling the grounds by Thestral-back and meeting all of the many animals and creatures that lived on the Hogwarts grounds. His stamina and riding endurance quickly increased until he could ride all day and only feel a little stiff after.
The grounds were more extensive than he had realized, encompassing the village of Hogsmeade and spreading out for acres in every direction. Slytherin explained that the four Founders had conquered and claimed the land, and had each been granted an Earldom for it. Technically the land was four separate lands, but the founders had signed a treaty that, in exchange for their peerages, they would never split them up, allowing Hogwarts to continue.
Harry met snakes who lived in the fields and gardens, such as the Greek agathos, the native Fenny, and the Lithuanian zaltys. All three were useful in keeping away pests and magically helping crops grow. One zaltys, named Adelyte, insisted on staying with Harry; visiting him in the castle and often accompanying him around the grounds, curled up on his Thestral's back.
Around the perimeter of the wards, Harry met several of the snake defenders; native vipers, adders, dispas, and seps, all with highly toxic venoms. Poisonous boomslangs from Africa and taipans from Australia also were homed along the ward boundaries, as were the masters of hiding, horned cerastes. Slytherin also introduced Harry to Hoop snakes from North America who could form themselves into a wheel, build up speed, and ram into attackers. He met Greek Jaculi and Fandrefiala from Madagascar, both of whom hid in trees before leaping into attackers like deadly venomous arrows. The latter was even capable of hypnotizing those who caught its gaze!
Some of the snakes even worked together, as they demonstrated for Harry. Among their other talents, the Australian Akurra could shoot a stream of water into the air, creating a rainbow if it was sunny, or a raincloud if it was not. The rainbow python would then use that rainbow or cloud to transport itself and the Akurra to the next location. They could make it from the furthest wardline to the castle in a matter of minutes that way!
The Runespoor was a three headed snake that made a wonderful lookout, as did the winged Tohil snake from South America. It could fly, and communicate with some magical bird species, and Slytherin had imported many of them to help defend the school and coordinate between the snake and bird defenders.
There were also snakes who would confuse the enemy. The Boiuna were large black snakes that lived in the lake and nearby rivers, and they could change their form to almost anything to frighten away attackers. Harry also found the Tsuchinoko particularly interesting. It could speak understandably to humans, but liked to lie. Slytherin told him of a camp full of enemy soldiers who kept hearing contradicting orders from their Knight leader and eventually turned on each other, thanks to one particularly eager Tsuchinoko.
In the bog on the far side of the estate, Harry was introduced to a pair of Mboi Tu'i serpents, who were waiting for their first clutch of eggs to hatch. Because of this, they were extraordinarily defensive, and even the two parselmouths were in danger of being seen as threats. They quickly left, but Slytherin assured Harry that he would study the creatures of the bog later, when it was a little safer to do so.
Finally, Slytherin took Harry to a rocky cave in the foothills. There he taught Harry a spell to make him impervious to magical heat and flame. Once they were both protected, they passed through a ward Gryffindor had specially designed and into what Harry thought a volcano might look like. Magical fires danced around the space, with huge chunks of burning rock scattered about. But there, Harry was introduced to quite impressive creatures. There were salamanders, which though related to snakes could not speak parseltongue. There were Falak snakes from Arabia, who enjoyed the fire and even seemed to breathe little tongues of flame! Several of the phoenixes came to visit, as they also enjoyed this environment.
Harry also met several baby ashwinders. As Slytherin explained, Ashwinder adults were created from the embers of magical fires and laid eggs, dying within the hour. When the eggs hatched, baby ashwinders were born. As long as they remained in a magical fire, the babies would remain alive, indefinitely. Slytherin proudly announced that some of the ashwinders here were over fifty years old! However, if they were ever to leave their magical flames, they would quickly become adults and enter the usual ashwinder life-cycle.
Harry could have stayed in the cave for hours, talking to the flaming creatures, but Slytherin warned him that the flame-proof spell would wear off. However, he promised that Harry could return in the future.
The snake Harry found the most impressive, besides Essa the Basilisk, of course, was Coatl, the Vision Serpent. It was extremely rare, and, like the Basilisk, Slytherin only had one. But one was all he really needed. Coatl could see what any other snake saw, and it could impart those images as a vision to a Parselmouth like Slytherin. It completely surprised Harry by showing him an image from Adelyte, currently curled around his wrist, giving him a snake-eye view of himself. He also showed Harry a vision from one of Adelyte's family, of Neville exploring a greenhouse with Hufflepuff and two other people. Harry thought it was incredible!