Hi Thom,
Like Mike mentioned, I think that culling through this information yourself with Excel will probably be your best bet for analyzing the data you mentioned.
I'll give you a few ideas on how I would start if I was you:
You mentioned that many of the queries were only searched once. I would start by organizing your information into two columns: one with the query, and one with the search volume. Then, I would filter those down to only queries that have been searched more than [a certain threshold]. I think that while queries that have only been searched once can give you valuable information, especially compared to others and analyzed in aggregate, you will be less overwhelmed if you start with the most important (and a smaller set of) queries first.
After you've done that, I would start to filter your data by query. You can sort by queries that contain, begin with, end with, or do not contain a term, or any sort of custom filter. Given your example, I would probably start with filtering by queries that contain the word "cat" or "dog" or "turtle," and then try to find trends within that smaller set of data. They will be much easier and less overwhelming to find when you are not dealing with so much data.
This next step is a little more tedious, but I would also recommend adding another column that you manually populate. You mentioned that there are misspellings; you could account for those by creating another column in which you populate the word "cat" for all queries that contain "cat" and also all queries that contain "cta" or any other misspelling. That way, later, you can easily sort by keywords that were about cats, but didn't necessarily contain the exact word "cat." Or, you could populate the column by grouping all queries that were about one animal, two animals, three animals, etc.
Once you have a ton of information, I would recommend creating pivot tables and charts that help you compare the data.
Ultimately, what I'm recommending is probably very time intensive and tedious, but I really think it will be rewarding once it's completed, because you will very thoroughly understand the trends going on in the data. One of the benefits of doing it yourself, rather than using a tool, is that you will understand the context around these words; you will be able to better interpret trends or make connections than an automated tool would be.
Here is a great article that walks you step by step through some of the steps I mentioned, and it also goes into depth about other ways you can use Excel to analyze this kind of data: http://www.sitevisibility.co.uk/blog/2015/09/11/4-excel-tips-applied-to-keyword-research/
Hope this helped!