This shows one of the options available in the animal details page. The screenshot was taken after clicking the 'Full Sibs' option in the page menu (shown in blue).
Pedserve can quickly display lists of related animals - in this case the full siblings of an animal (i.e. all individuals sharing the same parents).
Note the other options in the page menu for listing other relatives, with the counts shown. Relative counts are not available with Pedserve Standard Edition.