article_snippet.sent: – and frequent landslides reveal new ones, some of which belong to unknown species .
article_snippet.sent: Some, like the one pictured, are large .
article_snippet.sent: long and weighed up to 40 tonnes.
article_snippet.sent: ‘we can calculate their size and speed, find out about their behaviour and learn how their got around.'
article_snippet.sent: One set of tracks, for example, revealed two lines of prints with a smaller pair, suggesting a baby walked alongside a baby parents, while another set, now known as Johnny Walker, was made by a baby T.Rex.
article_snippet.sent: When some are removed, or crumble away, more are revealed underneath.
highlights_snippet.sent: Attraction is prone to landslide and is said to be under threat from humans .