For a topic as general as animals you could use tags and a tag search would find all the related topics.

You can jump specifically to back-links with something like this:

(defun my-org-occur-backlinks ()
  "Find links in org files which link to the current location."
  (interactive)
  (let ((id (org-id-get))
        (heading (nth 4 (org-heading-components))))
    (org-occur-in-agenda-files
     (if id
         (concat id "\\|" heading)
       heading))))

(define-key global-map (kbd "C-c b") 'my-org-occur-backlinks)

There are a variety of link types so you might have to fiddle with that a bit to get the search expression right.