An ant .... hole?

Grandma told us about these funny hole out under the pine tree by the pool.

What was strange is that these ants do not have hills just holes. Are they living under the pine tree for a specific reason?

Our research has not been very successful in pinpointing exactly what kind of ant this is. However we did come across some interesting facts about ants in general:

It is estimated that there are about 20,000 different species of ants. For this reason ants have been called Earth's most successful species. Ants build many different types of homes. Many ants build simple little mounds out of dirt or sand. Other ants use small sticks mixed with dirt and sand to make a stronger mound that offers protection from rain. Western Harvester ants make a small mound on top, but then tunnel up to 15 feet straight down to hibernate during winter. Ant mounds consist of many chambers connected by tunnels. Different chambers are used for nurseries, food storage, and resting places for the worker ants. Some ants live in wood like termites. Army ants don't make a home at all but travel in large groups searching for food