shook/shook up his mane

[user_gary]

The wolf went to the lion and said, "O king how is your health? I pray for your good health. I am always thinking of you. Does the fox visit you every day now?"
The lion shook up his mane and said, "Thank you for your kind words. Where is he now? He has not brought me any new medicine!"

I would have written that as "shook his mane and said............". I wonder why here "shook up" has been used.

 

[Anglika]

Because whoever wrote this is not really fluent in English.

"The lion shook his mane" is what I would have written.