Fig 2.TIF (3.41 MB)
Levels of difficulty.
figure
posted on 2016-05-06, 05:22 authored by Zita Polgár, Mari Kinnunen, Dóra Újváry, Ádám Miklósi, Márta GácsiThe different types of lids used for baiting in the five levels of difficulty. Each hole was 1 cm in diameter.