Scrutiny

As we emerged from the upper part of the wood, the dog and I, the sheep all turned to look at us before moving off.

You might think it's simply an instinctive response to disturbance but, like security cameras, they will have recorded our presence and may know us again.

A few years ago it was established that sheep, if rewarded,  could recognise up to 50 familiar human faces. One of those used in the experiment was Baarack Obaama's. 

https://www.bbc.co.uk/news/science-environment-41905652