Sloths are of an archaic mammalian order, and present simplistic arboreal behavior involving principally clinging, backdown hanging, and moving along the under sides of limbs. Cerebellectomy left them unaffected. Raccoons, diversified climbers of a higher evolutionary order, showed a classical postoperative cerebellar deficit, but compensated rapidly. Within a week they could hang from a limb. Soon they pursued upward climbing and could also swing back-down from the roofs of their cages. Complex, sometimes innovative, climbing followed. Cat controls lagged far behind.
Despite the wide evolutionary gap between sloth and raccoon they are allied in the prepotency of limb flexor as opposed to extensor musculature. Generalized seizures in raccoons are flexor (as also shown by Esplin and Woodbury for sloth); extensor seizures characterize most other species.
Murphy MG, O'Leary JL. Hanging and Climbing Functions in Raccoon and Sloth After Total Cerebellectomy. Arch Neurol. 1973;28(2):111–117. doi:10.1001/archneur.1973.00490200059008
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