Chinese martial arts have long been inspired by natural forms of movement and behaviours.
The form posture names reflect this quite clearly: stork spreads wings, snake creeps down, repulse monkey, part wild horses mane...

It is common for people to literally copy the mannerisms and actions of an animal.
Monkey is a common example of this, as is preying mantis.

Sifu Waller does not wish to behave like an animal. We are humans, after all.
The aim is to simply emulate the spirit of the animal.
We are interested in capturing the essence/nature/characteristics/quality of the animal.