The 25-cent Creatures of the Sea commemorative stamps went on sale October 3, 1990, in Baltimore, Maryland. The stamps feature the common dolphin, the killer whale, the northern sea lion, and the sea otter. It was the joint stamp issue by the United States and the Union of Soviet Socialist Republics.
The Northern Sea Lion and Sea Otter stamps were designed by Vladimir Beilen from USSR Ministry of Communications, and the Killer Whale and Common Dolphin stamps were designed by Peter Cocci from the Bureau of Engraving and Printing.
The stamps were printed in the offset/intaglio process and issued in panes of forty.
Postal Bulletin (August 9, 1990).