By default, when you select the Animals option, you will only see the first 25 records returned and only those animal records to which you have access rights to view and / or update (based on your role profile and which studies you are attached to as a user).
As explained in the Study User interface help, you can use the Choose option above each column of data to filter the list of animal records displayed. Use the Reset filter 
option to clear your search filters and display the complete list.
By default on page loading, Animals are sorted in the order of Cage, Visual ID and Unique ID respectively.
Use the 
functions to skip to particular pages or scroll through pages.
Note
If you cannot find an animal record in your list, it may be because other filters you have set, may remove it from your list. For example, if you set your Sex filter to Female, this will only display Female records, and it may be that you are looking for an animal by its ID value but can’t see it.