Mammalian Woodpeckers
Did you know that there are not one, but two mammalian woodpeckers? Well, they fill the same ecological niche as woodpeckers, at least!
The striped possum (Dactylopsila trivirgata) is a close relative of the Sugar Glider and lives throughout New Guinea, while the Aye-Aye is a proto-lemur (Daubentonia madagascariensis) that lives on the island of Madagascar.
Both of these creatures are percussive hunters. That is, they use parts of their body to tap on a surface (in this case, tree trunks) in order to locate their prey, which they then dig into the surface of the tree to extract.
While the woodpecker uses its beak to percuss, the aye-aye and striped lemur use their fingers, and the aye-aye is especially adapted for the job! Their long, thin middle fingers are full of far more nerves than other fingers, and they can often feel a grub's vibrations before they hear it. The extensive network of nerve endings means that the middle fingers require a large bloodflow to be effective, and as such, they're not "warmed up" until the aye-aye decides that it's time to hunt.
While the stripped possum is less adapted than the aye-aye to its particular niche (supplementing its diet with many free-wandering bugs and having good eyesight), its small ears betray its extremely sensitive hearing, and its prehensile tail allow it to reach where other vertebrates of the area cannot.
Images:
Proceedings of the Zoological Society of London. Illustrations by Joseph Wolf in 1908 and 1863.