Which Reindeer was Grandsanta's pet?

It looked like it was implied to be Rudolph, but the captions when they're in Africa says it's Dasher.
It reads:
[Dasher whimpers]
when the reindeer whines after they land in Africa....

Anyone know?

28 days, 6 hours, 42 minutes, 12 seconds. That is when the world... will end.