DETERMINANTS AND CONTROL OF UNDERWATER VOCALIZATIONS IN THE CALIFORNIA SEA LION.
Final rept. 1 Mar 68-30 Jun 70,
STANFORD RESEARCH INST MENLO PARK CALIF
Pagination or Media Count:
Experimental and observational studies were conducted to investigate factors influencing underwater vocalizations in the California sea lion Zalophus californianus and to determine the extent to which vocalizations can be controlled by conditioning techniques. The major findings were 1 Adult male and female Zalophus emit the same vocalizations under water as they emit in air. These are primarily a function of their social organization but also occur in nonsocial situations that may be considered arousal producing. 2 Male barking provides basic biological information regarding location in space, sex, age, and dominance status and is used in territorial displays and for herding females. 3 Male barking is seasonal and occurs most frequently during the reproductive season May-July, suggesting that hormones play an important role. 4 Barking rates by males are influenced by social context and by whether the vocalizations are produced in air or under water. 5 The underwater click vocalizations of Zalophus are susceptible to such subtle variations in stimulus control that they may be used to determine the absolute or differential sensitivity of these animals to selected aspects of their environment. In one such experiment, the underwater and aerial visual acuity of Zalophus was measured and found to be comparable to that of the domestic cat. Author
- Anatomy and Physiology