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Updated: Apr 7, 2026

Noninvasive, In-pen Approach Test for Laboratory-housed Pigs
Published on: June 5, 2019
Emily R Orlikoff1, Gene R Estrada1, Andrew J Marshall1,2,3,4,5,6
1Department of Anthropology, University of Michigan, Ann Arbor, Michigan, USA.
Wild orangutans (Pongo pygmaeus) primarily use quadrupedal fist-walking on the ground, often standing bipedally with extended hips and knees. Their adaptable positional behavior appears intrinsic, regardless of substrate.
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