1. The problem states that 1/7 of the animals in a pet shop are gerbils. 2. We need to find the ratio of gerbils to other animals. 3. Let the total number of animals be $T$. 4. The number of gerbils is $\frac{1}{7}T$. 5. The number of other animals is the total minus the gerbils: $T - \frac{1}{7}T = \frac{6}{7}T$. 6. The ratio of gerbils to other animals is therefore: $$\frac{\frac{1}{7}T}{\frac{6}{7}T} = \frac{1}{7} \times \frac{7}{6} = \frac{1}{6}$$ 7. So, the simplest form of the ratio of gerbils to other animals is $1:6$. This means for every 1 gerbil, there are 6 other animals in the pet shop.