Talking to Follows-Chalk about interesting wildlife in Zion will initiate this quest. Once it is received, head to Angel cave and go up the slope to the east of the camp. After maneuvering across the river over the three rock bridges, the Courier will find the Lost Mountain bighorner calf at the end of a narrow passage opposite the end of the last bridge.
In order to complete the optional part of the quest, the Courier mustn't get too close to any of the other bighorners, otherwise they will attack.
The Courier has to then to feed the lost calf a banana yucca fruit to get it to follow them. It is a good idea for the Courier to have three or four banana yucca fruits (there are 3 banana yucca plants along the route) as the calf periodically stops, and has to be fed another before it will continue. It can take 5–10 seconds after feeding for the calf to resume again.
The Courier should then return back across the rock bridges to the bighorner mother. They must then choose to either return the calf or keep it and if the former, speak to Follows-Chalk to complete the quest and receive the reward. If any bighorners were killed by the Courier in the process of completing the quest, Follows-Chalk will still give the reward. He indicates that he understands, but wishes they had not been killed. If no bighorners are killed, the player receives 25% more XP for the quest.
Find a way up to the Cliffs.
Find the lost Mountain Bighorner Calf.
(Optional) Don't kill any of the mountain bighorners.
Get the calf to follow you back to its mother.
Get the calf to follow you back to the herd.
Take the calf to Follows-Chalk.
Kill all of the Mountain Bighorners.
Speak with Follows-Chalk.
The bighorner calf can fall off the rocks, making travel difficult.
If a bighorner strays into the Dead Horses camp, the non-player characters may kill it if it becomes aggressive, causing the optional part to fail.
Having the Animal Friend perk will make this quest considerably easier.
A giant cazador may appear and attack the bighorners, which could cause the optional part of the quest to fail.
Successful completion of this quest yields a .45 pistol and a war club, both in perfect condition.
Occasionally, a Dead Horses tribe member may wander up the path leading to the bighorners herd. When this happens, he or she may attack the bighorners causing the optional portion of this quest to fail.
Don't forget to make any followers passive. If not, they will attack the bighorners on sight.
If the bighorner mountain mother is killed before starting the quest, it can still be successfully completed by returning the calf and talking to Follows-Chalk.
Occasionally, a bighorner may wander into a narrow pathway, causing issues especially when trying to go around it. Even when having the Animal Friend perk, Follows-Chalk may kill it if a bighorner becomes hostile.
PCPlaystation 3 Sometimes the calf will not follow you even if you offer it banana yucca fruit. [verified]