Everyone needs a ride!!!
Look, I'm as proud as any dwarf playing guy of the carrying capacity of my adopted race. But the fact is, everybody needs a ride.
It's just not right to walk into town with your supplies on your back, get drunk, pick up a nicely bearded lady dwarf, and then walk with her back to the clanhold.
You need a ride to show the world that you are a dwarf of substance and sophistication. A dwarf who knows how to buy a mine pony that won't let the family down or embarass the children when you drop them off at Junior Dwarf School.
More neatly, however, everyone in my party walks, I hate slowing 'em down and I want to make them see the beauty of actually riding something. As a druid I have some options for that, but I don't want to stray too far from from Dwarfish roots.
I like the ant idea, they wouldn't be as pathetic as mine ponies. And I could justify their having darkvision.
I looked at the Forgotten Realms riding lizard, but couldn't understand the encumbrance rules they had listed with it. According to what I understood, the lizard reaches light load at 130lbs, which struck me as too light for anyone much less an armored drow or duergar.
So I tried to compare it with the mounts in the PHB and couldn't discover anything about how they endured encumbrance either, except for how far they could travel in a day with a light load.
I don't understand why noone had put out a big book of mounts yet. Cavalry is the bomb.