Bite

Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) slashing damage.

Claws

Melee Weapon Attack: +4 to hit, reach 5 ft., one Medium or smaller creature. Hit: 4 (1d4 + 2) slashing damage and the target makes a DC 12 Strength check. On a failure it is knocked prone. If the target is already prone the ankheg can instead move up to half its Speed dragging the target with it.

Acid Spit

Ranged Weapon Attack: +3 to hit, range 30 ft., one creature. Hit: 4 (1d8) acid damage.