参考资料:[1] Ellison J. McNutt et al., (2021) Footprint evidence of early hominin locomotor diversity at Laetoli, Tanzania. Nature Doi: 10.1038/s41586-021-04187-7[2] Mystery solved: Footprints from site a at Laetoli, Tanzania, are from early humans, not bears. Retrieved Dec. 2, 2021 from https://www.ohio.edu/news/2021/12/ohio-university-researcher-footprints-site-laetoli-tanzania-are-early-humans-not-bears[3] Footprint Evidence of Early Hominin Locomotor Diversity at Laetoli, Tanzania. Retrieved Dec. 2, 2021 from https://mcnuttej.wixsite.com/ellisonmcnutt/laetoliaproject