Bears may be able to estimate and compare numbers of items. Jennifer Vonk of Oakland University in Rochester, Michigan, and Michael Beran of Georgia State University in Atlanta trained three captive black bears (Ursusamericanus) to distinguish between two groups of dots (pictured) displayed on a touch-screen computer. One bearrnwas trained to touch the grouprncontaining the most dots, and thernothers to select the group with thernfewest. By varying the size andrnpositions of the dots, researchersrntested whether the animalsrncould recognize dot numberrnindependently of the total arearncovered by the dots.
展开▼
