You know winter has arrived in Chengdu when Caesar starts to dig – and yesterday she dug for China. 

Bear Manager Donata radioed everyone on the walkie-talkie to come over and watch as our formidable and very beautiful brown bear chose what she obviously thought was a suitable spot by the fence-line and set to work. 

This wasn't how we saw it at all. My heart was in my mouth as she dug lower and lower into the ground, pausing every few minutes to back out of her home-made den in order to level the earth mountain growing outside.

I knew it should be OK really – remembering that when the enclosures were designed by Boris, our China Construction Development Director, the cement had gone a metre underground just to be "safe" – but my goodness Caesar was definitely testing it now. 

As she dug, I couldn't help remembering her life on the bear farm and the contrast to what it is four years on. She and her bear farm "room mate" Emma (a boy with a girl's name) had been cruelly shackled in a "full-metal jacket", in a cage, on the farm in Tianjin, northern China – for nine long years. 

The day of their rescue was bitterly cold – freezing rain driving down as our team cut the bars of the cages apart with blow torches as Caesar and Emma lay sleeping under anaesthetic. Then a quick health-check before being loaded into robust transport cages for a three-day road-trip – over land, over mountains, over night. 

It was one of the most incredible journeys of my life with Boris and Howard (our Bear Team Supervisor) – both still with us today – leading the whole operation professionally and effortlessly. The scenery as we drove from town to town and village to village was breathtaking – beautiful forests, snow-capped mountains and babbling rivers along the way - we even passed a cat on a hot tin roof!

The Chinese media followed throughout and as we drove into each town the villagers would pour out of their houses to see the spectacle of two huge bears rolling their way "home". 

It's clear that this is all long forgotten by Caesar, who was definitely on a mission today. In a few weeks, she will be moved into our new construction – "Caesar's bunker" – where she can dig dens to her heart's desire and stay outside for as long as she likes. For now, she'll have to be content snuggling up at night in her hanging-basket bed.

The team that looks after Caesar couldn't resist taking a closer look at her handiwork. Here's Li Ping, Zeng Zhi Pong, Zhang Jinguo, Tao Hongliang, Ou Jun, and Bear Manager Donata Baars checking out the hole.

So for now, our team will fill in the rather impressive hole, acknowledging that, in her normal and very determined style, she'll be back digging for China again tomorrow.