male Pacific walrus (O. r. divergens)

wild caught in 1978

deceased in 1984

Ancestors and Descendants


Transfer History

  1. capture 1978 on Wrangel Island, Russia

  2. transfer 1978 to Dolfinarium Harderwijk

  3. death 1984 at Dolfinarium Harderwijk

Physical Data

The dates listed here generally represent the time at which the measurements were published, not necessarily the date on which they were taken.


  • 1978: 60 kg · 132 lb

  • 1984: 750 kg · 1,653 lb


"The animals were fed 3 to 6 times per day on an average diet of 35% herring (Clupea harengus; approx. 8880 kJ/kg), 26% mackerel (Scomber scombrus; approx. 9550 kJ/kg), 9% sprat (Sprattus sprattus; approx. 10.400 kJ/kg), 2% whiting (Merlangius merlangus; approx. 4750 kJ/kg), and 28% squid (Illex spp.; approx. 1000 kJ/kg) by weight. Vitamins (Seavit>, 1 tablet per 2.5 kg of food) were added to this thawed diet." (R. A. Kastelein et al, 2000)

  • 1980: 5,500 kg · 12,125 lb annually

  • 1982: 6,000 kg · 13,227 lb annually

Image Gallery

No images available at this time.



Notes and Information

This walrus died of a tusk infection at 6 years of age.

Pjotter was estimated to have been born in June of 1978, and arrived at Harderwijk when he was 2 months old, placing his date of transfer around August.

Pjotter's skull is held in the collection of the University of Utrecht's Veterinary Faculty.


  • 1984-Jul-28. Leidsch Dagblad. Dolfinarium Harderwijk. Retrieved from Erfgoed Leiden.

  • 1990-Jan. R. A. Kastelein and N. M. Gerrits. The anatomy of the Walrus head (Odobenus rosmarus). Part 1: The skull. Retrieved from the Aquatic Mammals Journal.

  • 2000-Jan. R. A. Kastelein et al. Food consumption and body weight of captive Pacific walruses (Odobenus rosmarus divergens). Retrieved from researchgate.net [archive]