You can download videos using Safari. Firstly, go into Safari -> Preferences -> Advanced and turn on 'Show develop menu'. Next, navigate to the page containing the video you want to download. From the Develop menu select 'Show web inspector'. In the left hand panel find the video, it will usually be under 'Other' and start with the text "videoplayback", and click on it to select it. Then, in the right hand panel, under 'Location', select everything to the right of the text "Full URL". This is the URL to the video. Copy it to the clipboard and paste it into the address bar. Now, if you press Enter it will open a page containing just the video and play it. This is NOT what you want. So, instead of pressing Enter press Alt+Enter and this will download the video to your Downloads folder. It might sound a bit convoluted but it's actually quite straighforward, especially once you've done it a couple of times.