* The history of language is incredibly complex. We don't have records of every single word from the very beginnings of the English language.
* Animal names evolved over time. What started as a simple descriptive term could have changed into a more specific name as language developed.
However, we can make some educated guesses:
* Animals with basic, common names: It's likely that animals people interacted with regularly, like dog, cat, bird, sheep, and cow, would have been given names very early on.
* Animals with specific, descriptive names: Animals that were less common or had distinctive features might have gotten more descriptive names later on.
It's also worth considering that different dialects and regions of England might have had different names for animals.
Ultimately, the answer is probably lost to time!