irregular animal x3's

Situation:
There are four animal gismu with an irregular x3. These are: tirxu, vidru, lanme, and civla.

Proposal:
Remove the x3 of those words to make all the animals equal. 

Impact:
Usage breakage is inconceivable. The corpus shows zero uses of tirxu3 and five of vidru3, All the five lanme3 uses are jokes and insults. civla3 has 10 results, again including meta-jokes about the place structure.