I noticed some weird tiny holes on the trunk of a giant tree in my yard. I'm not sure if the previous owner used this tree as a dart board or what. Poking it, the tree bark kind of felt soft and bendable. I easily peeled some off to realize that there are ants or some kind of insect living inside the tree. Is this a sign that the tree is at risk of falling? I'm concerned since the tree has a slight lean straight towards the house.
What you're looking at there is not the bark, but the heartwood of the tree which has been exposed via some kind of injury to the outer layers of the tree. The heartwood is effectively "dead" anyway and does not play a major role in the tree's biological processes, but it does provide structural strength. The holes you can see are most probably created by some kind of insects, and it's likely that you will see further damage occur from birds going after the insects. This alone won't kill the tree as long as the outer, living layers can continue to move water and nutrients form the roots to the leaves. You can see plenty of very old hollow trees. But the more of the heartwood is eaten away, the more prone it will be to break in a violent storm.