The Refusal at Esk Ford

At Esk Ford the leading females turned upstream, carrying the herd towards a crossing which cost us four miles and most of the afternoon. Their herders attributed this preference to a habit established before the birth of any living mammoth. Sigrun Vold had watched her grandmother’s herd make the same diversion; her grandmother had attributed it to animals already dead. I accepted the observations and disputed the pedigree. Sigrun replied that a Royal Chair must be a comfortable place from which to judge a ford. I asked her to help me arrange a trial, since she had correctly identified the principal defect of my position.

On three mornings we brought two young animals to the ford before the herd arrived. Both had previously followed its upstream detour. With Sigrun beside them, each entered the shallows and crossed; when accompanying the older females, both turned away. I proposed that the females’ behaviour was sufficient to preserve the custom. Sigrun observed that she herself had always turned upstream with them. This was an embarrassing omission from my experimental arrangements, and therefore a useful one. We repeated the approach with her remaining downstream and offering the familiar crossing call. The older females still refused; the youngsters hesitated, then followed them. I withdrew my suggestion that the herders alone maintained the avoidance. Sigrun received the withdrawal with an economy of expression I recommend to my colleagues.

We had demonstrated one means by which an aversion could pass to animals that had never suffered its original cause; we had established neither its antiquity nor that original cause. The oldest females might remember an accident; they might dislike some present feature of the ford which escaped us. Their preference could recruit successive generations under either circumstance. I therefore allowed “inherited herd habit” in my account, with its meaning specified, and struck out “memory of the drowning”, which Sigrun’s nephew had supplied with considerable confidence. His authority was a song. I requested an independent record of a drowning at this crossing; none was produced. The song may eventually lead us to one, but until then it has no business in the conclusion.