• discrimination;
  • gray seal;
  • Halicboerus grypus;
  • habituation;
  • Phoca vitulina;
  • harbor seal;
  • human-animal interactions;
  • orientation behavior


Two pairs of harbor (Phoca vitulina) and three pairs of gray (Halicboeruls grypus) seals were exposed to one of three human handlers for 15 min, twice a day, for a total of six sessions. Following habituation to the familiar handler, animals were then exposed to a novel human for 7 min, and then retested for 7 min with the familiar human. In all cases, animals responded to the unfamiliar human with increased vigilant behavior, i. e., they spent more time oriented towards the unfamiliar handler during the first 2 min of the test session than during the same interval of either the final habituation session or the retest with the familiar human (P= 0.03 in all cases). There was also a tendency for seals to contact the familiar handler with their noses more rapidly than the novel human (P= 0.06). These results support the hypothesis that phocid seals are capable of discriminating between individual humans in their environment, setting the stage for human-based Pavlovian conditioning.