While there's no definitive answer to which mammal digs the absolute deepest burrows, strong contenders include:
Naked mole-rats: These subterranean social dwellers create vast networks of tunnels that can reach depths of up to 6 meters (20 feet) .
Meerkats: Though their burrows aren't as deep as naked mole-rats, reaching up to 5 meters (16 feet), their complex structures with multiple chambers and ventilation shafts are impressive feats of excavation .
It's important to consider factors like soil type and burrowing purpose when evaluating burrow depth. Some mammals might dig shallower burrows in hard-packed soil but have impressive tunnel lengths.
