The Hadrian's Wall Trail does not exactly teem with wildlife. Yes, there are birds and frogs and the occasional squirrel, but most of the animals one encounters along the path are of the farm variety. As an American who rarely sees sheep up close, I had to resist taking a picture of every lamb I encountered because, boy, were they cute. But sometimes I could not resist, like when a lamb tried to hide from me behind a trig marker or block my path or walk right up to me to check me out. I'm a sucker.
Lamb behind marker.
Lamb on path.
Lamb close-up.
I passed by a few interesting horses, including a piebald unfazed by my presence and a couple of equines tethered just outside a working suburban scrap yard.
Piebald pony.
Scrap yard horses.
Otherwise there were cows and donkeys and a lot more sheep. Sometimes they blocked my path, sometimes they played together, but they always provided a little bit of company on my long solo journey.
Cows and sheep living together.
Lots of company along the path.
Cows blocking my way.

Since much of the Hadrian's Wall Trail crosses privately-owned farmland bounded by fences and walls, there are several implements built to traverse these manmade obstacles. These implements are called "stiles". I was impressed by the different styles of stiles: some were "kissing gates", some were steps made of stone and some were steps made of wood. I crossed dozens, maybe hundreds of these over the course of seven days. I found them interesting from an engineering standpoint, and somewhat exhausting from a hiking standpoint.

Kissing gate stile.
Wooden step stile.
Stone step stile.