This why it's a good idea not to have too much content, or diverse topics in depth, on a single page.
If you cannot reduce the amount of content by sorting it into separate pages, adding a list of in-page links at the top of the page may help visitors find what they're looking for, once landed. This would require adding ids to elements that identify sections, such as headings, and making the id the href target of the link anchor. e.g.
In-page links list
<p>Elephants are well known for their large size, grey colour...</p>