div class=ts-pagebuttonPage 1button div class=ts-image a href=https:reader043vdocumentsusreader043viewer20220205235750683b1a28ab0f07af335ehtml5page1jpg target=_blank amp-img class=ts-thumb alt=Page 1: Hunger and Thirst: Knowing When to Eat src=https:reader043vdocumentsusreader043viewer20220205235750683b1a28ab0f07af335ehtml5thumbnails1jpg width=142 height=106 layout=responsive amp-imga divp© Nature Publishing Group1968pdivdiv class=ts-pagebuttonPage 2button div class=ts-image a href=https:reader043vdocumentsusreader043viewer20220205235750683b1a28ab0f07af335ehtml5page2jpg target=_blank amp-img class=ts-thumb alt=Page 2: Hunger and Thirst: Knowing When to Eat src=https:reader043vdocumentsusreader043viewer20220205235750683b1a28ab0f07af335ehtml5thumbnails2jpg width=142 height=106 layout=responsive amp-imga divp© Nature Publishing Group1968pdiv