The diggerundi split from its ancestor the noant. Like its ancestor it lives a lives a colonial lifestyle. A diggerundi colony can consist of hundreds of individuals. They have five castes: workers, farmers, soldiers, males and the queen. The workers do a multitude of tasks, such as digging and raising young. The farmers tend to "shrooms" by bringing them their poop and collecting water from the deep water table. The soldiers have huge buck teeth and guard the entrance. The queen mates with the males after each birthing cycle. Mostly females are born but now and then another male is birthed.
The workers are now strictly female, but only the queen reproduces. The males are fertile, while the females are sterile due to a hormone from the queen's urine-sweat; this is only temporary, though. When the queen dies, it is replaced by another female, which takes the position due to hormones. The queen gives birth every week, and the litter can be of up to ten babies. They are altricial, and need much care. They are retrieved by the workers, who gently place them in their cradle chambers.
Diggerundi house themselves by digging very deep burrows, containing many chambers; some of them are for resting places for the workers, and other chambers are for raising young, and one is for the queen only. There are also huge farming chambers which grow shrooms, which are tended by the farmer caste. They will travel down deep through the tunnels that lead to the water table and hold water in their mouth. They have extra puffy cheeks to hold lots of water. Since they breathe through their rears they can hold this water without having to hold their breath.
Even though they are farmers they are not above scavenging. When finding food, they "march" in trails similar to Earth ants. Diggerundi collect rotting fruit, rotting flesh from larger animals, and even dead or dying small animals.
In physical changes, the toes have now split where they have 3 normal toes and in the front and 2 digging toes in the back. These push more dirt. Their backwards butt-nostril now has a closing siphon to keep out the dirt when digging, and their eyes now have eye-lids to keep out the dirt as well. Their ears are smaller and towards the back of the head to reduce the soil that could fall into it.
Their squeaks are ultrasonic, and hence inaudible to larger animals. The incisors now on a trunk and is used like a shovel. Soldiers have the largest while the queens have the smallest trunk but their mouths are huge since they are constantly giving birth out of it. The mouth can stay closed now without worrying about eating dirt when digging.