I.M Johnston Otter Lutra 2 16 May. Stephens Passage Alaska 1.5 mi S of entrance to Snellisham 1400 A warm sunny day, gentle breeze. An otter was been standing on a rocky about four feet above the water, part of a rocky point that jutted about 30 yds out from shore. It was facing the water. After remaining still for about a minute, it began humping its rear end up and down. Kept this humping motion up for about ten seconds, making one up & down motion per second. It disappeared over the rocks.